About 15 years ago, scientists agreed that traits can not only be inherited from parents through DNA. A new study shows that epigenetic features can be passed down from generation to generation—“from grandparents to grandchildren.”
with active and inactivated H3K27me3 epigenetic marker nematode embryo
Scientists from the University of California, Santa Cruz (USA) have discovered the mechanisms of biometric and transmission of traits beyond the DNA molecule . It turns out that genetic information can be transferred not only from parents, but also from grandparents, biologists wrote in the journal in the journal Proceedings of the National Academy of Sciences .
People noticed the similarities between descendants and parents in ancient times, but until the 19th century, monk biologist Gregor Mendel and noble Imre Festrick gave scientific explanations on why this happened. Genetic characteristics of gene form are encoded in DNA and RNA molecules passed down from generation to generation. Genes themselves usually do not change throughout the life of an organism, and the reason for the new generation of mutations is that the genes of ancestors (not only direct, but farther) are shuffled like a deck of cards during sexual reproduction.
For a long time, scientists have believed that genes are the only mechanism for transmitting genetic information. That is, trait inheritance does not occur outside DNA and RNA. This means that those traits and traits that the body acquires in life cannot be passed on to its children. By the end of the 20th century, however, biologists found that this was not the case: epigenetic channels still existed in the transmission of traits. The essence of his work is that under the influence of various living factors (e.g., severe stress), the "activation level" of DNA and RNA changes. Because of this, the same genetic password can produce different results for parents and children.
American biologists from University of California used soil nematodes (Carean elegans ) to study one such mechanism. Under the influence of the epigenetic markers of H3K27me3, the DNA molecule is densely arranged, making it difficult for some genes to activate. Scientists removed this marker from chromosomes of nematode sperm and fertilized eggs with fully marked genes to determine what changes this would lead to.
As biologists expected, without H3K27me3, genes that are usually inactive are activated in offspring. This leads to various effects until some worms are infertile. But most interestingly, some genes are activated earlier than necessary—just in embryonic tissue, and usually they should start in already formed neurons. This acquired gene activation pattern is passed on to offspring.
According to Susan Strome, one of the authors of the study, any epigenetic changes in the germline can last for generations. This does not look like some of the strange features of nematodes, but rather like a conservative epigenetic mechanism, which is the characteristic of animals in general, including humans.
Therefore, a person's development will be affected by the living environment of his ancestors - not only directly affecting his parents, but also grandparents. However, it is not possible to test this hypothesis in humans at this time: genetic experiments involving humans are forbidden.
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