Genome size variation is associated with life-history traits in birds

Genome size markedly displays variation across taxa. Genome size variation is affected by two principally different mechanisms (such as whole-genome duplication events (polyploidization) and accumulation of noncoding elements). In addition, genome size variation is also affected by the phylogenetic signal, life-history traits and environmental factors. Here, we studied the relationships between genome size and life-history traits (e.g. clutch size, hatching time, fledging time, age at sexual maturity, longevity and body mass) among 240 species of birds using a phylogenetic comparative analysis and path analysis. We found that genome size was positively correlated with both body mass and hatching time. We also found that body mass was positively correlated with hatching time, age at sexual maturity and longevity in birds. Our findings suggest that although genome size was directly linked to body mass, evolution of larger genomes was also associated with larger bodies by the prolonged hatching time.