How snakes lost their limbs

This February 2018 video says about itself:

90 million years ago, an ancient snake known as Najash had…legs. It is by no means the only snake to have limbs either. But what’s even stranger: we’re not at all sure where it came from.

From the Fundação de Amparo à Pesquisa do Estado de São Paulo in Brazil:

Research explains how snakes lost their limbs

The study is part of an effort to understand how changes in the genome lead to changes in phenotypes

February 6, 2019

Snakes and lizards are reptiles that belong to the order Squamata. They share several traits but differ in one obvious respect: snakes do not have limbs. The two suborders diverged more than 100 million years ago.

Identification of the genetic factors involved in this loss of limbs is a focus of the article “Phenotype loss is associated with widespread divergence of the gene regulatory…