Fish Immunology (1+1)

Unit 2 - Evolution of immune system

2.3. Whole-genome duplication (WGDs)
The vertebrate genome has under gone two rounds of Whole-genome duplication (WGD) after the emergence of urochordates and before the radiation of jawed vertebrates. The first round of WGD occurred in a common ancestor of jawed and jawless vertebrates, and the second round in a common ancestor of jawed vertebrates. These WGDs played a crucial role in the emergence of adaptive immune system in jawed vertebrates, in the form like many ohnologues, that formed during WGDs, are now acting as an essential components of the adaptive immune system in jawed vertebrate.