Inference of evolution of vertebrate genomes and chromosomes from genomic and cytogenetic analyses using amphibians

Abstract

Amphibians, which first adapted to terrestrial life in vertebrates, appeared around 350 million years ago (Mya) after the common ancestors of tetrapods (amphibians, reptiles, birds, and mammals) diverged from ray-finned fishes around 410 Mya, and are therefore important model animals for understanding vertebrate evolution. To date, there are many cytogenetic reports of amphibians. Moreover, recent improvements in techniques for cytogenetic and genomic analyses help accelerate the accumulation of the cytogenetic and genomic data from amphibians. Inferred from recent genomic and cytogenetic analyses using amphibians, I review karyotype and chromosome evolution, including sex chromosomes, polyploidy, and origins of microchromosomes, in not only amphibians but also entire vertebrates.