A recent study from the USC Stem Cell lab has uncovered the surprising evolutionary origin of the mammalian outer ear, linking it to the gills of ancient fish and marine invertebrates. Led by Gage Crump, the research reveals that both structures are composed of elastic cartilage and shares gene control elements that hint at their connection. This finding sheds new light on the evolution of the mammalian ear, highlighting how structures can transform over time to serve new functions.

The short-beaked echidna (Tachyglossus aculeatus)  is one of Australia’s most iconic animals. Belonging to a unique group of mammals called “monotremes” (with the platypus as the other prominent member), echidnas may at first glance be mistaken for a weird-looking hedgehog, but they are in fact egg-laying mammals.  An international team of authors, led by Guojie Zhang and Qi Zhou at Centre for Evolutionary & Organismal Biology at Zhejiang University, Yang Zhou from BGI-research and Frank Grutzner from Adelaide University now present an almost gapless genome sequence of the short-beaked echidna. This work is part of the international Vertebrate Genome Project, and hosted in the VGP Genome Ark Database. The authors used the new data to better understand the evolutionary origin of the highly complex configuration of multiple sex chromosomes which is characteristic for monotremes. The work is published in the open science journal GigaScience.