FLICKR, USFWS NORTHEAST REGION
Species: Hellbender salamander (Cryptobranchus alleganiensis)
Genome size: 55 billion base pairs
The largest salamanders are only a few feet long, but their genomes, which range from 14 billion to 120 billion base pairs, outsize those of all birds, mammals, reptiles, and frogs. This genomic gigantism likely stems from a disproportionate expansion of repetitive DNA sequences, according to research published last month (June 23) in Genome Biology and Evolution.
Previous studies have correlated salamanders’ colossal genomes with changes to their skeletal and circulatory systems, reduced neural complexity and lower rates of cell division and differentiation. Biologists Cheng Sun and Rachel Lockridge Mueller of Colorado State University sequenced the hellbender salamander genome and compared it to that of six other distantly related salamander species. They found that ...
