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...