Ecological patterns of genome size variation and the origin of species in salamanders

TL;DR

This study reveals that in salamanders, genome size variation correlates with ecological and evolutionary factors, with larger genomes linked to lower diversity and smaller ranges, suggesting a role in species diversification and extinction risk.

Contribution

It demonstrates non-random patterns of genome size variation among salamander lineages and links these patterns to ecological and evolutionary dynamics.

Findings

Genome size varies inversely with species richness.

Older salamander lineages tend to have smaller genomes.

Larger genomes are associated with lower diversification and higher extinction risk.

Abstract

Salamanders (urodela) have among the largest vertebrate genomes, ranging in size from 10 to over 80 pg. The urodela are divided into ten extant families each with a characteristic range in genome size. Although changes in genome size often occur randomly and in the absence of selection pressure, non-random patterns of genome size variation are evident among specific vertebrate lineages. Here we report that genome size in salamander families varies inversely with species richness and other ecological factors: clades that began radiating earlier (older crown age) tend to have smaller genomes, higher levels of diversity and larger geographical ranges. These observations support the hypothesis that urodel families with larger genomes either have a lower propensity to diversify or are more vulnerable to extinction than families with smaller genomes.