Fish Genetics & Ploidy

The genetic architecture of fish - including polyploidy (multiple chromosome sets), whole-genome duplication events, and rapid adaptive evolution.

System: Reproductive Level: Advanced Discipline: Cellular

📖 Overview

Fish have some of the most flexible genomes in vertebrate biology. Two whole-genome duplication events at the base of vertebrates - and a third in ray-finned fish - laid the genetic foundation for the radiation of 33,000+ modern fish species. Some salmonids, carps, and sturgeons are naturally polyploid (4-8N chromosome sets).

🔑 Key Concepts

Polyploidy, whole-genome duplication, sex determination, genetic sex vs phenotypic sex, hybridization.

🐟 Examples

Sturgeons have 4N-8N ploidy levels. Common carp are tetraploid. Some triploid salmon strains are induced commercially for sterile aquaculture.

✨ Fun Fact

A single salmon has roughly 90,000 protein-coding genes - about 3x more than a human - largely due to ancient whole-genome duplications.