[troutman]

My old genes!

the oldest known functioning gene is the one that codes for the enzyme glutamine synthetase, which creates the amino acid glutamine from glutamate and ammonia. As this enzyme is a crucial part of the way cells make protein and remove excess nitrogen, natural selection has preserved it unchanged. Every living thing uses this same gene that first evolved more than two billion years ago – before even the first cells with a nucleus emerged.

https://www.google.ca/amp/s/www.scie...in-humans/amp/