LLife would probably be easier with a long, flexible and mobile tail, which would accompany us at every step. There was a time, very long ago, when our ancestors had a tail. The question then arises: why do we no longer have a tail today?
Let’s go back about 20 million years, to the time when our hominid ancestors, the first great apes, separated from other primates and lost their tail appendage. At that time, the tail played a crucial role: it helped maintain balance during acrobatic movements through the trees of dense forests, a real asset for our primate predecessors.
But the course of evolution can be capricious. A genetic mutation, a small insertion in a key gene called TBXT, has upended this established order. The mutation, discovered by Bo Xia, a medical doctoral student at New York University, came as a revelation after he injured his tailbone in 2019. Intrigued by the vestigial structure, Xia and his team set out to genetically compare apes with and without tails. They identified a particular sequence that, by inserting itself into the TBXT gene, prevented tail formation in great apes, including humans.
The remains of our embryonic tail
Interestingly, all humans briefly have a tail in the embryonic stage. Around the sixth week of development, a small […] Read more
