The repetitive structure of the duplicated regions makes them particularly difficult to study using standard genetic approaches - the most efficient methods for sequencing DNA start by chopping up the genome, reading the sequence of the small chunks and then assembling those sections like one would a puzzle. Eichler and others don’t know what spurred the initial rounds of duplications or how these regions, dubbed “core duplicons,” reproduced and moved around the genome.ĭespite the duplication-linked genes’ potential importance in human evolution, most have not been extensively analyzed. Much about the duplication process - and its implications - remains a mystery. In September, Eichler’s team published a new technique for analyzing how these genes vary from person to person, which could shed more light on their function. Over the past few years, scientists have begun to uncover the function of a handful of genes that reside in these regions they seem to play an important role in the brain, linked to the growth of new cells, as well as brain size and development. “My feeling is that these duplication blocks have been the substrate for the birth of new genes.” “I think it’s a missing piece of human evolution,” said Evan Eichler, a geneticist at the University of Washington, in Seattle. This unusual pattern, repeated in different parts of the genome, is found only in great apes - bonobos, chimpanzees, gorillas and humans. But as these “dandelion seeds” dispersed, they carried some grass and daisy seeds - additional segments of DNA - along for the ride. Small pieces of DNA replicated and spread across their resident chromosomes like dandelions across a lawn. From Quanta Magazine ( find original story here).Ībout 8 million to 12 million years ago, the ancestor of great apes, including humans, underwent a dramatic genetic change.
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