Genome Size Diversification in Central American Bolitoglossine Salamanders (Caudata; Plethodontidae)

Genome sizes (expressed as C-values, or haploid genome sizes) of six species of Honduran plethodontid salamanders (one species of Nototriton and five of Bolitoglossa) vary greatly. Nototriton has a moderate-sized genome (29.2 pg) relative to other species of salamanders. Genome sizes in the species of Bolitoglossa span a range of 24 pg (similar to 23.4 gigabases) of DNA and include the largest genomes (83.7 pg) reported for the genus and for the family Plethodontidae. A phylogenetic analysis indicates that genome evolution in this group of salamanders featured mainly large increases in the mass of nuclear DNA. We propose that these evolutionary changes in genome size reflect random drift in small, isolated populations in the highlands of Central America.