The information ‘deleted’ from the human genome may be what makes us human

According to a new study led by researchers at Yale and the Broad Institute of MIT and MIT, what the human genome lacks compared to the genomes of other primates makes up for the development of humankind as much as what it has added over the course of our evolutionary history. Harvard.

The new findings were published April 28 in the journal Science, fills an important gap in what is known about historical changes in the human genome. While a revolution in the ability to collect data from the genomes of different species has allowed scientists to identify additions unique to the human genome—such as genes that are important for humans to develop the ability to speak—it has received less attention. What is missing from the human genome.

For a new study, researchers used an even deeper genomic dive into primate DNA to show that the loss of nearly 10,000 bits of genetic information — what separates humans from chimpanzees throughout our evolutionary history. Our closest primate relative. Some of those “deleted” pieces of genetic information are closely related to genes involved in neuronal and cognitive functions, including the formation of cells in the developing brain.

These 10,000 missing pieces of DNA—present in the genomes of other mammals—are common to all humans, the Yale team found.

The fact that these genetic deletions have been conserved in all humans, the authors say, attests to their evolutionary significance, suggesting that they have some biological advantage.

“Often we think that new biological functions must require new pieces of DNA, but this work shows us that deleting the genetic code can have serious consequences for the traits that make us unique as a species,” said Steven Reilly, of Yale School of Medicine. Assistant Professor of Genetics said. Medicine and senior author of the paper.

This was one of several published in the paper Science From the Zoonomia Project, an international research collaboration that catalogs the diversity in mammalian genomes by comparing DNA sequences from 240 species of mammals extant today.

In their study, the Yale team found that some genetic sequences found in the genomes of most other mammalian species, from mice to whales, have disappeared in humans. But rather than disrupting human biology, they say, some of these deletions created new genetic encodings that removed elements that would normally turn genes off.

The effect of deleting this genetic information, Reilly said, was the equivalent of removing three letters—”no”—from the word “is not” to create a new word.

“[Such deletions] Humans can change the meaning of the instructions on how to make them, which helps explain our large brains and complex cognition,” he said.

The researchers used a technology called Massively Parallel Reporter Assays (MPRA), which can simultaneously screen and measure the function of thousands of genetic changes in a species.

“These tools have the potential to allow us to begin to identify the many small molecular building blocks that make us unique as a species,” Reilly said.