Lysenko’s great contribution to the understanding of heredity
This is the second of a series of three articles that LALKAR is publishing to mark the 130th anniversary of the year of the birth of Joseph Stalin.
This article is based on a presentation given by Godfrey Cremer to the Stalin Society in London on 18 March 2007
This subject is daunting. It is very difficult to find authoritative agreement with Lysenko. His supporters are few and far between among current biologists, let alone specialists in genetics or evolution.
To even consider saying “Lysenko is right”, therefore seems presumptuous and preposterous. Yet it is a conclusion that just does not go away. However much he is dismissed and even ridiculed, the main thrust of his work and argument has not been disproved, and new findings keep reopening the question. The conclusion I reach is that Lysenko is right.
Background and context of Lysenko’s work
Let us first look at the background against which the controversy in which Lysenko was a major protagonist took place. We will consider the roles of Lamarck, Darwin, Mendel, Morgan and Weismann, before considering the contributions of Michurin and Lysenko.
We must not of course forget that Lenin and Stalin both played important roles in the controversy. We must also not forget the contribution of Marx and Engels. Their great contribution to the development of dialectical materialism had considerable influence on the work of the Lysenko school. Working in science in the Soviet Union was a very different matter to conditions in the West. Lysenko took part in wide-ranging debate, initiated by the Communist Party, which involved the general public as well as the farmers of the state and collective farms.
Jean Baptiste Lamarck
Jean Baptiste Lamarck (1744 to 1829) was a French naturalist who suggested that organisms changed and change was inherited. He put forward this idea of the inheritance of acquired characteristics. An example that he gave was the giraffe. He suggested that as giraffes reached for higher leaves on the trees their necks stretched and got longer, and that this was passed on to their offspring. Over generations, longer and longer necks would result.
Lamarck did not attempt to show the mechanism by which this happened. He did not suggest what might have gone on in the body of organisms to bring this about. He is important because he did start thinking about living things changing and that change was inherited, and he introduced the idea that things that happen to an organism during its lifetime can be passed on to its offspring. His theory of the inheritance of acquired characteristics is very significant.
Quite a bit later than Lamarck comes Charles Darwin (1809 to 1882). His con-tribution was that he put forward an understanding of evolution in a systematic way. He backed up his arguments with a large amount of wide-ranging evidence. He acknowledged the work and ideas of others, but his work was by far the most thorough.
Darwin, an English scientist, concluded that species of animal and plant had not been specifically created as they were, but had developed from ancestors by a process of change. It was a very revolutionary theory because it cut right across the clerical idea of special creation, creation of each species by God.
Darwin went further and suggested a mechanism by which evolution could happen. He suggested that within the variation that existed among individuals of a species, those that were best suited to the environment stood most chance of surviving and breeding. In this way the features best adapted to the conditions were passed on to offspring, and by repetition of this process species gradually changed. He called this natural selection, where the best features were naturally selected by the environment. He compared this with the way that stock and plant breeders selected the best individuals to breed from in order to produce types that they wanted.
Darwin observed the undoubted existence of variations within species of plants and animals. He did not suggest how they come about. He certainly did not dismiss the idea that variations arise, at least partly, as a result of modifications of the bodies or behaviour of organisms in their interaction with their surroundings. At one point he did suggest that there were ‘gemmules’ in the blood that carried such information to the sex cells (the ova and sperm cells) in animals.
He certainly did not dismiss Lamarck out of hand, as others who claim to have ‘developed’ Darwinism have tried to do.
That is the initial background: that features are inherited, and the inheritance of variations, selected by the environment, causes changes in organisms; that they develop by a process of evolution.
Now we consider Gregor Mendel (1822 to 1884). His work was not known to Darwin, and in fact it remained in obscurity for many years. He was a monk who had unsuccessfully tried to follow a teaching career and concentrated on working in the gardens of the monastery in Brünn (or Brno) which was then in the Austro-Hungarian Empire and is now in the Czech Republic.
Mendel worked on peas and developed a way of isolating the flowers and pollinating them with pollen carefully collected from another plant. His methods enabled him to breed between individual plants, and know precisely which were parents of which seeds and hence of which offspring. Mendel’s work has for a long time been on the syllabus of GCSE and A-level science courses. It carries the authority arising from this and has been heard of by many people. But in order to consider its significance we need to look at it a little more closely (for further study, any school biology text gives a good account of detail).
Mendel selected various features in peas that contrasted with each other. Some pea plants had green seed coats while some had yellow seed coats. Some of them had smooth seeds and some had wrinkled seeds. He looked at several features including the fact that pea plants could be tall or dwarf.
Mendel’s tall and dwarf pea plants
He found that he could produce tall plants which when crossed (mated together) always produced tall plants. Likewise he could produce dwarf plats which when crossed among themselves always produced dwarf plants. He called these “true breeding”.
When he crossed a true breeding tall plant with a true breeding dwarf plant all the offspring were tall. It seemed that the ‘dwarfness’ had disappeared.
However, when he crossed these new tall plants with each other he found that they were not true breeding, both tall and dwarf plants appeared in their offspring. By breeding a large number of such offspring he also found that on average there were 3 tall offspring for every one dwarf offspring; a ratio of 3:1. This has been called a Mendelian ratio.
All the dwarf offspring he produced in this way were themselves true breeding. That is, if they were crossed among themselves they produced only dwarf offspring.
The tall plants in this group, however, were not all the same (although they looked the same); some were true breeding, but some were like their parents, that is, they produced both tall and dwarf offspring if crossed with each other, in the Mendelian ratio of 3:1.
Mendel found similar results for a few other features of pea plants, some of which have been mentioned above.
He explained these results by a theory that each plant had two factors influencing a particular type of feature. So for texture of seed coat, he suggested a factor for ‘smoothness’ and a factor for ‘wrinkledness’; and similarly a factor for ‘tallness’ and a factor for ‘dwarfness’, and so on for the other features he studied
His true breeding tall plants had two ‘tallness’ factors. His true breeding dwarf plants had two ‘dwarfness’ factors. When crossed among themselves, tall with tall or dwarf with dwarf, these were the only factors they could, respectively, pass on to their offspring, so all offspring were the same as their parents – true breeding.
He said that each plant had two factors for this very noticeable difference in height, but passed on only one in pollen or ovules. This would mean that when pollen and ovule joined to form a seed there were again two factors, one from each parent.
In this way Mendel gave an explanation for the results he found when he crossed true breeding tall plants with true breeding dwarf plants. The tall parent passed on a ‘tallness’ factor in every pollen grain or ovule it produced. Similarly the dwarf parent passed on a ‘dwarfness’ factor in every ovule and pollen grain. This meant that all the offspring had one factor for tallness and one factor for dwarfness. But all these offspring were tall, as we have seen above. So Mendel said that the factor for tallness overrode the factor for dwarfness – he said tallness was dominant and dwarfness recessive. These were tall plants, but they were hybrids
Although these plants all looked tall, because of the dominant tallness factors, they all also had a factor for dwarfness (which was not having any effect on how they looked).
This is how Mendel explained what happened when two hybrids were crossed.
Mendel suggested that if a parent had two different factors for a feature, then it was a matter of chance which went into a particular pollen grain or ovule. So there was an equal chance that a pollen grain or ovule produced by a tall looking, hybrid, plant had a factor for tallness or a factor for dwarfness.
There was also an equal chance that, when they joined after pollination, one type of factor or the other from one parent would meet up with one type or the other factor from the other parent.
Possibility 1: A tallness factor from parent A can meet a tallness factor from Parent B, giving two tallness factors. (Tall plant)
Possibility 2: A tallness factor from parent A can meet a dwarfness factor from parent B, giving a factor for tallness combined with a factor for dwarfness. (Tall plant)
Possibility 3: A dwarfness factor from parent A can meet a dwarfness factor from parent B, giving two dwarfness factors. (Dwarf plant)
Possibility 4: A dwarfness factor from parent A can meet a tallness factor from parent B, giving a factor for tallness combined with a factor for dwarfness (Tall plant, as in the second possibility above).
This is ingenious. These possibilities are equally likely, and there are three possibilities of getting tall looking offspring (1,2 and 4) and one possibility of getting dwarf offspring (3). This gives the Mendelian ratio of 3:1.
Even more, it explains how some of the tall offspring are true breeding (1), because they only have factors for tallness and if crossed together that is the only type passed on. But some of the tall looking offspring have a factor for tallness and a factor for dwarfness (2 and 4), these are not true breeding, they are hybrids.
These crossings can be shown by diagrams, to be found in school text books, which give a more visual explanation of Mendel’s theory.
Mendel also said that when two different features were considered, they were passed on independently of each other. So if tallness or dwarfness and wrinkled or smooth seeds were considered at the same time, they joined up independently, and gave a second Mendelian ration of 9:3:3:1. We will not go into that further here, but working it out is fun if you want to follow it up or explore a text book.
Mendel’s published work
Mendel published his work in the proceedings of the Brünn natural history society (Volume 4 of 1866). It was hardly noticed, until ‘discovered’ at the beginning of the 20th century.
His experiments, as they stand, are repeatable. It is true that they only work for a few features. It has been suggested, on the basis of a statistical consideration of features of pea plants that Mendel might have chosen to study, that the chance of him only selecting the ones he did is very remote, and that he discounted results which did not fit his theory. That, however, does not affect our consideration here.
Mendel’s ratios can be shown to work for the features he did report on. They can also be shown to work for some features in other plants and animals including, for example, the inheritance of haemophilia in humans.
But many features are not inherited in this simple way. It is claimed that the inheritance of features which do not behave according to Mendel’s theory is controlled by a complicated interplay of many contributing ‘factors’, too complex for ratios to be calculated.
We have spent a bit of time on Mendel, and with good reason. His work is often quoted as the basis of genetics, but modern genetic theory contains claims that do not depend on, and indeed cannot be derived from Mendel’s work. But because Mendel is so widely taught, and his experiments can be shown to work, it is easy to be convinced that this is the experimental basis (and hence proof) of modern genetics.
This, however, is far from the truth. It is, therefore, necessary to emphasise what Mendel did say, and to understand how far his theory went. It is necessary to try to dispel the mysticism which incorrectly holds him up as an authority for those parts of genetics with which Lysenko took issue.
It is very important to note that Mendel’s theories say nothing about what his ‘factors’ actually were. Mendel also has nothing to say about how these ‘factors’ might change, or even whether they could change, or whether new ones could emerge to replace them.
So, though Mendel’s work is often quoted as the basis of genetics, modern genetic theory has been developed to have basic tenets that do not depend on, and indeed are not a necessary development from, Mendel’s work.
Lysenko and the Lysenko school did not dispute Mendel. As far as his work went, it was accepted. What was disputed by Lysenko was the ‘development’ of Mendelism (as well as the ‘development’ of Darwinism) as we shall see below. And this dispute was one which arose in the very practical field of improving Soviet agriculture.
‘Development’ of Darwin and Mendel
We can now go on to consider the “developments” of both Darwin’s theories and Mendel’s theories.
Two very important people among those who were involved in this “development” were August Weisman, a German biologist working towards the end of the 19 century, and Thomas Hunt Morgan, an American geneticist working in the first part of the 20th Century.
Weismann, propounded a theory that inheritance was the function of “germ plasm”. This germ plasm was only in the gametes, the reproductive cells (in many animals these are sperm and eggs and in many plants they are within the pollen and ovules). He said that the rest of the body, made up of somatic cells, had no influence on the germ plasm. In other words, nothing that happened to an animal or plant during its lifetime could change the germ plasm.
The germ plasm determined what the body of the organism was like (its form), how it worked (its functioning), and its behaviour. This meant, according to his theory, that acquired characteristics could not be inherited. Weismann, therefore, unlike Darwin, opposed and even ridiculed the ideas of Lamarck.
Weismann thus stated that the germ plasm passed from generation to generation determining the structure and functioning of individuals, but was isolated from them. He realised that for evolution to happen there had to be variation among individuals and changes in body form and function. He maintained that these changes were the result of random mutations in the germ plasm. These mutations could be inherited and this was what produced the variations between organisms of the same species upon which natural selection could act. If the mutation produced an advantage, the individuals that had it would be more likely to reproduce and the mutation would become the norm; if it was not an advantage the mutation would, sooner or later, be eliminated.
In passing it is worth noting that there is a sense in which the environment, according to Weismann’s theory, could affect the germ plasm. That is when mutations are induced by environmental agents such as radioactive radiation (e.g. X-rays) and certain chemicals. Their effect, however, is random damage (mutation). Acquired characteristics, by contrast, are changes which happen in a directional way in response to concrete conditions of the environment, and which according to Weismann cannot be inherited.
The basic tenet of Weismann’s theory is that the ‘substance’ of heredity, what he called the germ plasm, was independent of the body of living organisms. While the germ plasm determined the structure and functioning of individuals, it was not affected by their life, being passed on unchanged (except for random mutations) to the next generation, and so on.
It is this contention with which Lysenko and the Lysenko school fundamentally disagreed. Lysenko, as we shall see, disagreed with this neo-Darwinian theory of Weismann, not with Darwin himself as many try to maintain.
Thomas Hunt Morgan
But before we come to Lysenko’s work, we must also consider the significance of Thomas Hunt Morgan. He was an American embryologist and geneticist. Following the rediscovery in about 1900 of Mendel’s work, he carried out experiments on the fruit fly, whose scientific name is Drosophila melanogaster. Many fruit flies can be housed in a small space and they reproduce about every 12 days. He investigated the inheritance of several traits with basically similar results to those Mendel found for pea plants.
What had also been discovered were the chromosomes that could be seen in plant and animal cells using light microscopes, usually when cells were in the process of dividing. They were so called because they were strands, or ‘bodies’, that could be dyed with coloured stains in order to see them under a microscope. They generally appear in pairs (Drosophila cells have 4 pairs, human cells 23 pairs). When cells divide during normal growth each chromosome doubles itself and one of the two so formed goes to one of the new (daughter) cells while the other goes to the other daughter cell. This happens to both of each pair of chromosomes. In this way each cell has a full compliment of pairs of chromosomes.
When gametes (see above) are produced by cell division something different happens. Instead of each chromosome dividing, only one of each pair goes to one daughter cell (now a gamete) while the other goes to the other daughter cell. This means that gametes have only half the complement of chromosomes – only one of each of the previously existing pairs.
At fertilisation, when male and female gamete fuse together, the two half sets of chromosomes meet, and once again there is a full set of pairs.
Morgan noticed the similarity of this behaviour of chromosomes to the postulated behaviour of the factors in Mendel’s theory. He adopted the term ‘gene’ in place of ‘Mendel’s factor’. It was clear that chromosomes were not genes – there were not enough chromosomes even for the rather small number of genes necessary to control the traits in Drosophila that he studied. Morgan suggested that that there were many genes arranged along the length of each chromosome. He found that some genes for different traits always seemed to keep together and suggested that they were linked by being on the same chromosome and he used the concept that chromosomes sometimes broke and rejoined to calculate the position on chromosomes of genes for particular features.
He was, of course, only able to do this for the limited number of fruit fly traits that behaved according to Mendel’s laws.
The key feature of Morgan’s theory, however, took up Weismann’s idea of the ‘barrier’ between germ plasm and the somatic cells. Morgan attributed this feature to chromosomes and what he claimed were their long chains of genes. He said that these behaved in the way Weismann said that germ plasm behaved. He proposed that genes could only change by random mutations.
He said that each cell of the body of an organism contained a full set of pairs of genes situated on pairs of chromosomes. These genes would influence the behaviour of the cells, they determined the structure and functioning of the organism. But he said that the genes were passed on to offspring unaffected by what happened to the organism during its life in its interaction with its environment.
It is clear that this was not part of Mendel’s theory. Mendel’s work provided no proof for this tenet of Morgan’s. It was a ‘development’ of Mendel’s theory that is claimed to provide an explanation of the neo-Darwinian ideas of Weismann and others. Like Weismann, Morgan proposed that the only basis on which natural selection could act was on variations that occurred as the result of random, accidental, mutations to genes.
To emphasise; although this idea has become incorporated in, and is central to, neo-Darwinism and the ‘Mendel-Morganist’ genetic theory, it is not contained in the work and theories of either Darwin or Mendel themselves.
Now we come to consider Michurin and Lysenko.
Ivan Vladimirovich Michurin
Ivan Vladimirovich Michurin was a Russian horticulturalist who worked mainly on fruit trees. He was born into an impoverished aristocratic family in Russia in the mid eighteen hundreds. Growing and developing fruit trees was the love of his life. His father had orchards and his great grandfather had grown some quite important varieties of fruit trees.
When Michurin was about 20 his family split up and they became very poor. He had to gain work as a railway clerk. At the same time he continued to grow trees in the rest of the time available to him, selling some to finance his experimental development of new varieties, until he was able to finance his research entirely in this way.
Michurin emphasised the importance of the way in which his plants were raised. They could not be treated any old how, but had to be grown very, very carefully indeed. He found, moreover, that by being extremely careful about the conditions in which he tended his plants he could get favourable changes to happen to them as they grew. Moreover, these changes were in certain cases passed on to their offspring.
Michurin thus repudiated the work of Morgan and Weismann. He maintained that the genetic theory of inheritance could not explain the results he saw in his work. He put forward a theory of heredity in which me maintained that what was inherited from parents was not merely structures which could only change at random, but a whole metabolism.
Metabolism is the sum total of the very complex chains of chemical reactions that go on in the cells of living organisms. Michurin maintained that this metabolism could be modified by the environment, particularly at crucial developmental stages, and that the modified metabolism could be passed on to offspring. This view was clearly in opposition to the Weismann and Morgan theory of the ‘barrier’ preventing any influence on genes by the environment of the organism.
Not only did Michurin rely on evidence of inherited changes that resulted from his careful husbanding of his plants. He also showed that by grafting one type of variation on a stock plant of another type, he could produce changes in the graft that would have only been expected by breeding and changes in genes. He suggested that it was the metabolism, the chemistry, of the stock and of the graft that interacted.
Lysenko was a Soviet agronomist educated at technical training institutions rather than university. He worked on the practical development of plants for Soviet agriculture. He started off working on legumes (plants of the pea, bean and other pulses group) and found that, by growing plants under different temperature conditions, varieties which were thought at one time to be only suitable for one part of Russia could be trained so that they could become suitable to grow in other parts of Russia where it was colder or hotter. In this way it was possible to expand the range of really good varieties.
Lysenko was successful in his work and was given charge of an institute. He worked on a whole range of plants particularly cereals – wheat, rye, barley and oats. He also, by the way, worked on millet which had been a very poor plant, not growing very well. It was developed by Lysenko and his colleagues so well and it became such an important and good crop that it made an important contribution to feeding the Red Army in the second world war.
Lysenko pioneered vernalisation of wheat. Some cereal plants, if planted in the spring, never grow, the seeds just do not germinate (begin to grow). Or if they do germinate they do not grow properly and they do not produce any ears, no grains, no new seeds.
It was discovered that these types of wheat needed to be in the ground for a period of very low temperatures before, given warmer conditions, they would germinate. This was a good adaptation to climates with very cold winters. If the seeds were shed and began to grow on relatively warm autumn days, severe winters would kill the young seedlings. It was better for the seeds to remain dormant to survive the winter. The requirement for a period of low temperature before seeds would germinate ensured that the seeds grains did remain dormant through the winter and that germination did not begin until the following spring.
There were some parts of the Soviet Union where it was impractical to plant these seeds in the winter, the only time they could in practice be planted was in the spring, but then they would not grow, or at least would not yield any seeds.
Vernalisation was a process which partly germinated the seeds under controlled conditions of moisture , air and temperature – including definite periods of cold temperature. These seeds could be planted by the farmers in the spring. This is quite a time consuming task, but Lysenko was not working in some kind of ivory tower laboratory. Every state farm and many collective farms in the Soviet Union had their own small laboratory with a technician in it, maybe an agronomist and an animal husbandry technician. And in all the areas there were small laboratories carrying out research. And these were linked up with the bigger laboratories which linked with the research in the universities. Lysenko was a very practical scientist and a very practical worker. He organised vernalisation on a large scale in state and collective farms. In this way good varieties of wheat could be grown in vast areas where before it was impractical.
Lysenko, however, went further than this. He germinated winter wheat under careful conditions, varying and controlling the temperature as the plants grew. He subjected them to periods of cold conditions, but not quite cold enough to kill the seedlings. He treated seeds produced by these plants in the same way and gradually developed spring planting varieties of what had been winter wheat. This induced change was then passed on to future offspring, it became inherited. It removed the need for laborious vernalisation and further extended the use of good varieties of wheat.
It is clear that Lysenko’s work was similar to that of Michurin It is also clear that it repudiated the theories of Weisman and Morgan. Lysenko developed and promoted Michurin’s ideas of heredity
One of the accusations made against Lysenko and his followers was that they did not understand genetics. But in fact Mendel-Morganist genetics was taught thoroughly in Soviet schools and universities. All the genetics departments and schools in the universities in the Soviet Union were initially founded on this type of genetics. What is more, those commentators from the West who went to the Soviet Union remarked on how well Mendel-Morganist genetics was taught compared to the way it was taught in Britain and America.
In the West the subject was very much an academic one, whereas the Soviet Union was intent on improving its agriculture, and heredity in animals and plants was a practical issue and the matter was treated seriously. Mendel-Morganist genetics, however, was in fact providing very little practical application to plant and animal breeding in either the West or in the Soviet Union.
Lysenko thus developed his work and theory in the context of a good understanding of the theories put forward by Weismann and Morgan. The fact that on the basis of his practical findings he disagreed with those theories and followed the work of Michurin, did not mean that he did not understand the former.
It is claimed that Lysenko’s experiments could not be repeated by others. But his work required painstaking care and dedication in nurturing plants during their growing stages and seeking to modify them at critical times to produce favourable changes. It required carefully controlling and changing the environment in a way that would elicit a response from the plants that could become embedded in their inheritance. It is perhaps not so surprising that those who, on theoretical grounds, said that this was impossible could not achieve it.
By contrast some of the other experimentation that had been carried out to prove that acquired characteristics could not be inherited were very crude. Weismann himself conducted experiments where he cut the tails off many mice or rats for over thirty generations. He found that not one individual in these generations was born without a tail.
He concluded, quite rightly, that the ‘acquired’ characteristic of having no tail (i.e. by having it cut off) was not inherited. However, there are acquired characteristics and acquired characteristics. This loss of tail by a sudden cut has very little resemblance to the changes induced by both Michurin and Lysenko as the result of subtle interaction between organism and environment. It is difficult to see how the former could influence in any directional way the metabolism which influenced the development of mouse tails. But that the metabolism of the plants in Michurin’s and Lysenko’s work could change to cope with carefully controlled but challenging changes in their environment, and that such metabolic changes could be inherited is a theory that requires respect.
“The Organism and the conditions required for its life constitute a unity. Different living bodies require different environmental conditions for their development. By studying these requirements we come to know the qualitative features of the nature of organisms. Heredity is the property of a living body to require definite conditions for its life and development and to respond in a definite way to various conditions” (Address by Lysenko in The Proceedings of the Lenin Academy of Agricultural Sciences in the USSR, 31 July – 7 August 1948, FLPH Moscow 1949, p.35).
You will be told that an acorn always grows into an oak tree; or that a chicken always hatches from a chicken’s egg. Is that true? Certainly not. If you put an acorn in a box in your attic, do you get an oak tree growing through the roof? No, the conditions in your attic are not those required by an acorn for its growth. Similarly, our breakfast time experience tells us that chickens’ eggs do not always produce chickens!
It is certainly true that an acorn will not grow into anything other than an oak tree. It will do so when it has the conditions that it requires, but it will grow into an oak tree that has some variations from its parents. And Lysenko claims that these variations are, at least in part, derived from changes in the metabolism of the parents in response to conditions in their environment, rather than random mutations.
It has been necessary to consider the work of Darwin and Mendel and the theories of Weismann and the work and theories of Morgan. This is important as a context for considering Lysenko. It has been important in order to at least indicate some of the mysticism and confusion which claims that Lysenko did not understand genetics, that he was ‘anti-Darwin’.
Now we need to have a look at more recent work, because it is claimed that this work has disproved Lysenko. We will see that this is far from the truth.
We have to consider a bit of chemistry. Not in order to become chemistry specialists, but to get some idea of what is being claimed and make some evaluation. This will also be useful for those who might want to look at basic text books.
Pure substances (elements) are made up of minute particles, the smallest particle you can get of a pure substance. These particle are called atoms. The smallest particle of carbon (coal, diamond, graphite) is an atom of carbon. It is different to an atom of oxygen or sulphur, and they are different to each other and to atoms of all other elements. (There are smaller particles than atoms, but fortunately we do not need to consider them here.)
Elements can combine together to make other chemical substances. These are called compounds. Atoms join together to make the smallest particles of compounds and these particles are called molecules (consisting of two or more atoms). Different compounds are formed from the atoms of different elements in different proportions and arranged in different ways.
One atom of carbon can combine with two atoms of oxygen to make a molecule of carbon dioxide, which is a compound very much in the news as a greenhouse gas.
Chemists use symbols to represent atoms, often the initial letter of the element except where they duplicate. Carbon is C, oxygen is O and Hydrogen is H, but because iodine is I, iron is Fe (from ferrous).
These symbols help to indicate molecules. Carbon dioxide can be shown as CO2 (indicating one atom of carbon and two atoms of oxygen)
Many of the chemicals that exist in the bodies of living organism are compounds made up of large numbers of atoms. A molecule of a simple sugar, glucose, has six atoms of carbon, six atoms of oxygen and 12 atoms of hydrogen (C6H12O6). Diagrams which give an indication in two dimensions of the relative arrangement of these atoms can be found in school text books.
Glucose is very important in the metabolism of living things. Plants, in their cells, make glucose from carbon dioxide and water by a long chain of chemical reactions, with many intermediate compounds. They need energy from sunlight to do this. Both animals and plants gradually dismantle molecules of glucose, again by a long chain of reactions, resulting in water and carbon dioxide and at the same time making energy available for the organism to use.
These are examples of metabolism, but they are only a small part of an organism’s total metabolism.
Proteins are very important chemicals. There are many different types, but their structure is basically similar. They are long chains of smaller molecules called amino-acids. There are about 20 kinds of amino acid found in living organisms. Long chains of these arranged in many different proportions and many different sequences can thus result in a very large number of different proteins. It is similar to to imagining the many different very long necklaces that could be made from a big stock of beads of 20 different colours and shapes.
Cells make the proteins that they need. The process of protein synthesis is an important part of metabolism. Once made, proteins become part of structure, enter into other chain reactions and, because enzymes are formed by proteins, play a vital role in controlling the myriad of chemical reactions of metabolism.
DNA is short for deoxyribose nucleic acid. This acid is also long chain molecules. The spine of the chain is repeated alternate sugar and phosphate units. This is quite boring, but four different types of molecule, called bases, join on to the sugars to make spurs. We can simply call them A,C,T and G (but they are fairly complex compounds, not elements – you can look up their full names if you need to).
In 1953 Watson and Crick demonstrated the structure of the DNA molecule. It was suggested that the A,C,T and G molecules formed the letters of a four letter alphabet that was arranged in ‘words’ along the length of the DNA molecule. It was also suggested that the ‘words’ represented different amino acids.
There are about 20 amino acids. Four letters can make 16 different two-letter ‘words’ (not enough) but they can make 64 different three-letter ‘words’. These triplets of the four bases are more than enough to represent the different types of amino acid.
It is thought that the sequence of these triplets, arranged along the DNA, can determine the order in which amino acids are joined together when proteins are made by cells. This order determines which protein it is. A particular strand, or part of a strand, of DNA can therefore ‘code’ for a particular protein, because it is the number and sequence of amino acids that makes the protein specific.
Watson and Crick’s important discovery was that two strands of DNA can join together side by side. They are connected by joins between the bases that stick out at the side. Because of the shape and size of the different bases, A will only fit against T and C will only fit against G. This means that if one stand of DNA is formed against an existing strand, then it has to form a ‘mirror image’ of bases. The sequence of bases in one strand determines the sequence of bases in the other.
Watson and Crick found that the only way these two strands could lie side by side in three dimensions was as the famous double helix.
This has provided a biochemical theory for how a blue-print for each protein can be contained in the DNA molecules. It is suggested that very small bits of nucleic acid with only three bases join on to amino acid molecules. Those with a particular triplet of bases join on to a particular amino acid. When the DNA double helix unzips, these bits with triplets somehow line up against the appropriate triplet on the DNA and pull the amino acid into position relative to the other amino acids, which then join together to make the specific protein molecule.
It has also provided a biochemical theory about how the information stored on the lengths of DNA can be replicated when new strands are built up against existing ones, making exact copies.
All this is put forward as proof for the gene theory of Morgan. While it is still not quite clear what a gene is, there is some agreement that it is a portion of DNA that has the ‘code’ for a particular protein. It may well be that the ability or not to produce a particular protein is what causes pea plants to be tall or dwarf, or have wrinkled or smooth coats to their seeds.
It is also suggested that if the DNA is damaged, then a particular protein cannot be made, or perhaps the ‘code’ gets shuffled so that the amino acids are arranged in a different order and a different protein is made. It is said that in most cases of such damage the effect is fatal and the fertilised egg or seed does not develop. In a few cases it may live, and in a very few cases it may give an advantage to the individual.
The idea is that then in this last case, by natural selection, such individuals and their offspring, which inherit the damaged and then copied DNA, stand more chance of breeding. This is the idea of mutations, which Weisman and Morgan and their followers claim only happen randomly.
But this, again, is the key to this argument. The above account of DNA and its role in heredity is very possibly true. But there is nothing in that account which proves that DNA molecules only change as the result of accidental, random damage.
When we look further at the complexity of the metabolism of living things, there is still a lot to be explained. There is certainly the possibility that more than the DNA is involved in heredity.
The position of all the bases on the DNA of an organism has been named the genome. There was much media coverage when the human genome was documented.
A very interesting thing to emerge is that most of the sequences on the DNA in the human genome have been termed rubbish. They have not been decoded as representing any proteins. The sequences that have been identified as coding for proteins are many fewer than were expected. If these represent the genes, then the human genome has fewer genes it was thought to have.
That may well be so. More recent work indicated that some bits of DNA do not code for protein, but tell the other bits when to make particular proteins. It is thought they switch them on and off and they are called ‘switches’. Further work has indicated that the switches or bits like them tell how much of a protein to make, what concentration to maintain and so on. This effect of switches has been called epigenetics.
This is very useful, because all the cells of a human body have the same chromosomes and hence all the genes. But different cells do different things, liver cells do not behave like skin cells. The ‘switches’ may help to explain that in different circumstances different bit of the DNA code become active.
Some of this information as well as more detail, can be found in a book called The Intelligent Person’s Guide to Genetics by Adrian Woolfson (published in 2004 by Duckworth Overlook). It is very readable, but note that the author does adhere to the Mendel-Morganist view of genetics, and neither Lysenko nor Michurin appear in the bibliography or index! It is, however, useful because it brings together and comments on quite recent developments in research into the behaviour of DNA and the chemistry of cells and inheritance.
In Woolfson’s book there are references to very complicated reactions going on within the DNA as it is taking part in the chemistry of the cell (the metabolism). Some bits of DNA apparently wander about and repair other bits that have become damaged. Some bits will not work except under the influence of sections far away from them on other strands. There is work showing that in times of stress there can be significant reprogramming of the activity of DNA over only a few generations.
It is clear that there are a lot of complicated chemical reactions taking place both between different bits of DNA and between the DNA and other complex chemicals in cells. It is also clear that somehow or other what happens in a particular cell is determined by the surroundings of that cell – its environment. Similarly what is going on in the sum total of the cells is responding in a great variety of ways to the environment of the individual organism.
In 2005 there was a programme on BBC Horizon called ‘The Ghost in your Genes’. This programme dealt with epigenetics, the study of the switches – influences which switch genes on and off, etc. Among other things it suggested that there is evidence that things like nutrition and stress (i.e. environmental factors) can control the switches and cause heritable effects in humans. There was a report of research by Marcus Pembrey, a professor of clinical genetics at the Institute of Child Health in London, in collaboration with Lars Olov Bygren, a Swedish researcher. They studied records of people in a remote town in northern Sweden where parish registries and detailed harvest records showed that environmental effects were passed down through generations. For example, a famine at critical times in the lives of grandparents affected the life expectancy of grandchildren. It is further suggested that simple environmental effects can switch genes in mouse embryos on and off, and that these changes could be inherited. The BBC report of the programme stated that this research demonstrated that genes and the environment are not mutually exclusive but are inextricably intertwined, one affecting the other.
This is one relatively small amount of research, and it cannot be taken as a final word. It does however give support to opening up the question, as we are doing here, of whether Lysenko was right.
Lysenko has been dismissed and ridiculed in the West and eventually even in the Soviet Union for going against the orthodox theories of evolution and genetics of Weisman and Morgan. But rather than giving proof of the correctness of Weisman and Morgan, as many have tried to maintain, developments in the understanding of the complex biochemistry of living organisms, seem to be moving in a direction of supporting Lysenko.
The essence is, to emphasise it yet again, that the environment and changes brought about by the environment, can, in appropriate circumstances, influence the heredity of the organism.
Lysenko quoted Michurin’s motto as: “we cannot wait for favours from nature; we must wrest them from her” (ibid. p.34)
Genetically modified crops
Genetically modified crops are a topical issue. This is again claimed to be a vindication of Mendel-Morganist genetics. The idea put forward is that a piece of DNA (which is named a gene) is inserted into the seed of a plant. It not only affects the way the plant grows or behaves, perhaps providing immunity to a particular pest. It can also be passed on to the offspring.
It does however seem to be equally possible to say that a complex chemical (a section of DNA) is inserted and becomes part of the metabolism of the plant, and this can be inherited. There is nothing that says that the environment of the plant cannot affect metabolism just because a chemical can be introduced artificially. Neither does the fact that it can be done artificially mean that change within the plant can only happen by random accidents.
In passing it must be noted that in the hands of monopoly capitalist seed producers and under the system of monopoly capitalism the main effort will be to secure profit. It will not be to work painstakingly to understand and prevent unwanted and perhaps disastrous additional effects.
Indeed while ‘genetically modifying’ seeds produced for sale to farmers, steps are also taken to ensure that the resulting seeds produced on the farm are infertile! Each year the farmer has to buy fresh seed from the monopolies. This situation does not encourage much confidence in things being done in the interests of ordinary people.
This brings us back to considering Lysenko’s work.
Lysenko and his supporters, as well as Joseph Stalin (who gets blamed for everything), have been accused of subjecting science to the ideological demands of Marxism-Leninism. Nothing could be further from the truth.
The legacy of Darwin is a revolutionary understanding of evolution, of change, of how living organisms change to become better adapted to their surroundings, and change to meet the demands of changes in their surroundings.
Darwin’s work unleashed a tiger. He established that species, previously thought to be stable and immutable, developed and changed. They developed. They became new species as a result of their interaction with the environment. It became harder to claim that anything was immutable, was here for ever. It became harder to claim that any system, including social systems of humans, were unchangeable and here for ever. Yet that was what capitalists wanted to claim for capitalism.
So Darwin was not just a challenge to orthodox religious doctrine. The bourgeoisie realised full well that his work was also a challenge to their political interests. Marx and Engels, in the field of both philosophy and political economy, had explained, and were explaining, the driving forces of the development of human society, and were showing how the system of capitalism, which itself had developed from feudalism, no longer suited the conditions, which themselves had been brought about by the development of capitalism. They were showing how society was moving towards a revolutionary overthrow of capitalism and its replacement by socialism. In this context the scientific work of Darwin was dangerous for the bourgeoisie.
And what happened? People like Weisman and Morgan had to come along as instruments in attempting to tame the tiger and draw its teeth. It is they who tried to impose bourgeois ideology, on science. They had to introduce the concept of change being based on random, rather than directional, changes.
They had to impose the scholastic ideology of a substance of inheritance that could not be affected by the life of an organism. It is very similar to the ‘ideal’ cat, the notion of ‘catness’ that exists, perhaps in a supernatural being, that is reflected in real cats, which approximate to it. Rather than the term ‘cat’ being the result of generalising from the many real cats that exist.
These notions were not there in the work of Darwin, or even of Mendel. It is not Darwin’s fault that in studying the world as it is and as it changes he should (without consciously realising it) be consistent with dialectical materialism.
It is equally not Lysenko’s fault that his work, and the work of Michurin before him, should be consistent with dialectical materialism. Nor is it Lysenko’s fault that he pointed out the bourgeois ideological concepts intrinsic to Neo-Darwinism and Mendelian-Morganist genetics.
That was not what introduced ideology as a factor more important than the what actually exists in the real world. It was Weisman, Morgan and their followers who have attempted to imposes ideology on science, not Lysenko and his followers. And the ideology they have tried to impose is bourgeois ideology.
Lysenko is opposed, or mostly ignored, by many eminent scientists. Yet in spite of this, the more this whole matter is looked at, the more his theories appear to be consistent with reality. New research, while apparently causing confusion because it raises questions about orthodox genetics, the genetics of Morgan, seems to be laying the ground for a better understanding of what Lysenko was saying, and a better understanding of heredity in living organisms.
Lysenko has not been proved wrong. However, in the theories of the opponents of Lysenko there is much that is inconsistent, is unsubstantiated, and does not accord with reality. Lysenko’s work, which was very important in the development of Soviet agriculture, in the building of socialism, cannot easily be dismissed, and promises to reassert itself.
We will leave the last word, or two words, to Michurin, who was the inspiration for Lysenko. Michurin had worked for many years under very difficult conditions and by 1914, at the age of 60 he wrote the following, which is an extract from a brief autobiographical note.
“Throughout the many years of labour devoted to improving varieties of fruit plants in Central Russia, I never received any subsidies or grants from the state, let alone thousand rouble salaries. I worked the best I could on the means that I obtained by my own labour. Throughout the past period I constantly struggled against poverty and endured all kinds of hardship silently. I never asked for assistance from the government so that I might more extensively develop this work so highly useful and so very necessary to Russian agriculture. On the advice of eminent horticulturalists, I submitted several memoranda to our department of agriculture in which I tried to explain the vast importance and necessity of improving and increasing native varieties of fruit bearing plants by raising local varieties from seeds. Nothing came of these memoranda. And now, at last, it is too late – the years have gone by and my strength is exhausted. For my part, I have done what I could; it is time to rest and take care of myself, especially since I constantly feel the effects of failing health and diminishing strength.
“It is very painful, of course, to have laboured for so many years for the common good with no recompense and then to be deprived of security in old age. The consequences are that I shall have to go on with my arduous work to the end – an unenviable prospect.” (I.V.Michurin Selected Works Foreign Languages Publishing House, Moscow, 1949, p 2 – first published in 1914 in Sadovod, No 6)
That is what Michurin wrote in 1914. Lenin recognised the importance of Michurin’s work, and after the revolution in 1917 he was put in charge of a horticultural station and that developed so that his work was used throughout the Soviet Union. When he was 80, Stalin sent him a telegram to mark 60 yeas of his work, to which Michurin replied by telegram. Michurin also wrote the following letter to Stalin, with which we will finish.
“Dear Joseph Vassarionovich!
“The Soviet system has transformed the small undertaking which I started on a mean garden plot 60 years ago for breeding new fruit varieties and creating new plant organisms into a vast Union-wide centre of industrial fruit breeding and scientific plant breeding, with thousands of hectares of orchards, magnificent laboratories and facilities and dozens of highly skilled researchers.
“And myself, a lone experimenter, unrecognised and ridiculed by the official savants and bureaucrats of the tsarist Department of Agriculture, the Soviet system and the Party which you lead have made me the director and organiser of experiments with hundreds of thousands of plants.
“The Communist Party and the working class have given me everything I need – everything an experimenter can desire for his work. The dream of my whole life is coming true: the valuable new fruit-plant varieties which I have bred have gone from the experimental plots, not into the possession of a few kulak money-bags, but into the far-flung orchards of the collective and state farms, displacing old inferior varieties of low yield. The Soviet Government has conferred upon me the highest reward a citizen of our country can receive, by naming the town of Kozlov the town of Michurinsk, awarding me the Order of Lenin and publishing my works on an impressive scale.
“For all this, as a token of my gratitude, devotion and love, all of my 60 years’ work is dedicated to you, the beloved leader of the working masses who are building a new world, a world of joyous labour.
“Dear Joseph Vassarionovich! I am 80 years of age, but the creative energy surging among the millions of workers and peasants of the Soviet Union fills me too, old man that I am, with eagerness to live and work under your leadership for the good of the socialist development of our proletarian state.” (ibid, p.14 – first published in Izvestia, 20 September 1934)
What a contrast between the writings of an old man of 60 and a young man of 80!