Why is the axolotl genome so large?
As a group, salamanders have larger genomes than the other amphibians.
It doesn’t appear that the axolotl has more genes than other vertebrates (Smith et al., 2009).
It is likely that the genome is large because of repetitive DNA content. The function of repetitive DNA content in the axolotl genome is unknown.
To learn more:
Voss, S.R., Kump, K.D., Putta, S., Pauly, N., Reynolds, A., Henry, R.J., Basa, S., Walker, J.A., and Smith, J.J. Origin of avian and amphibian chromosomes by fusion, fission, and retention of ancestral chromosomes. Genome Research 8:1306-1312.
Smith JJ, Putta S, Zhu W, Pao GM, Verma IM, Hunter T, Bryant SV, Gardiner DM, Harkins TT, Voss SR. 2009. Genic regions of a large salamander genome contain long introns and novel genes. BMC Genomics 10:19.