Open AccessA populational survey of 45S rDNA polymorphism in the Jefferson salamander Ambystoma jeffersonianum revealed by fluorescence in situ hybridization (FISH)
Author(s) -
Ke Bi,
James P. Bogart,
Jinzhong Fu
Publication year - 2009
Publication title -
current zoology/environmental epigenetics/current zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.971
H-Index - 38
eISSN - 2058-5888
pISSN - 1674-5507
DOI - 10.1093/czoolo/55.2.145
Subject(s) - biology , fluorescence in situ hybridization , ribosomal dna , ribosomal rna , population , intraspecific competition , biological dispersal , genetics , chromosome , zoology , phylogenetic tree , gene , demography , sociology
The chromosomal localization of 45S ribosomal RNA genes in Ambystoma jeffersonianum was determined by fluorescence in situ hybridization with 18S rDNA fragment as a probe (FISH-rDNA). Our results revealed the presence of rDNA polymorphism among A. jeffersonianum populations in terms of number, location and FISH signal intensity on the chromosomes. Nine rDNA cytotypes were found in ten geographically isolated populations and most of them contained derivative rDNA sites. Our preliminary study provides strong indication of karyotypic diversification of A. Jeffersonianum that is demonstrated by intraspecific variation of 45S rDNA cytotypes. rDNA cytotype polymorphism has been described in many other caudate amphibians. We predict that habitat isolation, low dispersal ability and decline of effective population size could facilitate the fixation and accumulation of variable rDNA cytotypes during their chromosome evolution.