2023-05-02 20:00:00
It is not so much what we can find in our genome as what is no longer there that could have led the human species to become what it is today. At least this is one of the main conclusions reached by a team of researchers from the Broad Institute, attached to the Massachusetts Institute of Technology -MIT-, and the universities of Harvard and Yale, who affirm that what is missing from the human genome compared to the genomes of other primates it could have been as crucial to the development of humanity as what has been added during our evolutionary history.
The new findings, published on April 28 in the journal Sciencethey fill an important gap regarding what is known about the historical changes in the human genome. And it is that, until now, the recent revolution in the capacity of Collecting vast amounts of data about the genomes of different species has allowed scientists to identify specific genetic factors in the human genome that make it unique: one example is the gene called FOXP2, fundamental in the development of speech, a quality unique to our species. However, until now very little attention has been paid to what is missing in the human genome.
With this new approach in mind, the team led by Yale University School of Medicine professor of genetics, Steven Reillyexhaustively compared the human genome with that of other primates, thereby demonstrating that over the course of our evolutionary history the loss of approximately 10,000 pieces of genetic informationmost as small as a few DNA base pairs, is one of the subtle differences that separate humans from chimpanzees – our closest primate relative.
How much do you know about DNA?
These 10,000 missing pieces of DNA (among the 300,000,000 that make up our genome) are present in the genomes of other mammals. The scientists also found that it is deletionsthat is to say, loss of genetic fragments, common to all human beings; and that many of them were associated with genes involved in neural and cognitive functions, some even associated with the formation of cells in the developing brain.
The fact that these gene deletions have been conserved in all humans, the authors argue, provides evidence for their evolutionary importance, suggesting that conferred some biological advantage. “We often think that new biological functions must require new pieces of DNA, however this work shows us that removing the genetic code can have profound consequences for the traits that make us unique as a species,” explains Reilly, whose article is one of 12 published in the journal Science within the framework of the Zoonomia Project, an international investigation in which the genome of 240 mammals is compared.
Have we human beings stopped evolving?
In their study, the Yale team discovered that some genetic sequences found in the genomes of most mammalian species studied, including everything from mice to whales, disappeared in humans. “Such deletions they can slightly modify the meaning of the ‘how to make a human’ instructions, which helps explain our larger brains and our capacity for cognition,” he continues.
“The removal of this genetic information, Reilly concludes, had an effect equivalent to removing the letters ‘n’ and ‘o’ from the sentence ‘is not’ to create a new word: ‘is’, giving rise to precisely what we are today.
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