Researchers from Yale and the Broad Institute have discovered that the lack of certain genetic information in the human genome, compared to the genomes of other primates, may have played a vital role in the development of humankind. Published in Science, the findings provide an important insight into the historical changes that have occurred in the human genome.
The study used a comprehensive genomic analysis of primate DNA to reveal that the absence of about 10,000 pieces of genetic information, as small as a few base pairs of DNA, over the course of human evolution, differentiates us from chimpanzees, our closest primate relative. Some of these "deleted" genetic pieces, known as hCONDELs, are closely linked to genes responsible for neuronal and cognitive functions, including one associated with the formation of cells in the developing brain. The researchers found that these missing genetic pieces, which are present in the genomes of other mammals, are common to all humans.
The researchers noted that the fact that hCONDELs are present in all humans indicates their evolutionary importance and suggests that they may have provided some biological advantage. The study found that these genetic deletions resulted in new genetic encodings that eliminated elements that would normally turn genes off. As a result, the deletion of this genetic information contributed to the development of larger brains and more complex cognition in humans.
To characterize the hCONDELs, the study utilized Massively Parallel Reporter Assays (MPRA), a technology that can simultaneously screen and measure the function of thousands of genetic changes among species. The researchers noted that such tools have the capability to identify the many small molecular building blocks that make us unique as a species.
Overall, the study highlights the importance of the absence of genetic information in human evolution and challenges the belief that new biological functions necessarily require new genetic material. The findings also underscore the significance of comprehensive genomic analysis in understanding the evolutionary history of the human genome.