Scientists Map 700 Million Years of Animal Chromosome History — and Find the Changes Are (Almost) Never Undone

A massive genomic survey of nearly 6,000 animal genomes reveals that once chromosomes fuse and scramble, evolution rarely lets them go back

Every animal alive today, from jellyfish to jaguars, carries in its chromosomes a kind of genetic scar tissue, traces of ancient mergers, breaks, and shuffles that occurred hundreds of millions of years ago and were apparently never undone. That is the central finding of a sweeping new study published in Science Advances, which analyzed 5,821 chromosome-scale genomes spanning 4,454 species and 19 animal phyla to reconstruct, in unprecedented detail, how animal chromosomes have changed — or stayed the same — since the dawn of the animal kingdom.

The study, led by Lehigh University’s Darrin Schultz while he was at the University of Vienna, and Arno Blümel, Dalila Destanović, Fatih Sarigol, and Oleg Simakov of the University of Vienna, draws on genome sequencing data that has exploded over the past decade, growing from just 45 chromosome-level animal genomes in 2015 to thousands available today. Using this trove, the team built what they call "evolutionary genome topology," a set of computational tools that let them compare genome architecture across enormous evolutionary distances — something that direct DNA sequence comparison usually cannot do once species have diverged for hundreds of millions of years.

Read the full story on CAS News.