Many of today’s marine invertebrates, including sponges and jellyfish, have chromosomes with the same ancient structure they inherited from their primitive ancestors more than 600 million years ago, according to a new study.
The surprise finding is a reminder that evolution is conservative — it keeps things that work well, like the organization of genes on a chromosome — and provides a key link between creatures alive today, including humans, and our very distant ancestors.
“It emphasizes that even in something as fundamental as their chromosomes, diverse animals resemble each other,” said the study’s senior author, Daniel Rokhsar, the Marthella Foskett Brown Chair in the Department of Molecular and Cell Biology at the University of California, Berkeley. “That’s one of the reasons why we can learn so much about human biology from studying fruit flies, nematode worms, jellyfish and other ‘simple’ model systems — it’s because of the underlying unity of all animals. What we learn about animal diversity affects how we think about ourselves.”