Conservation of chromosome 1 in turtles over 66 million years

Fluorescence in situ hybridization of a whole chromosome 1-specific probe f rom the yellow-bellied slider turtle (Trachemys scripta) to cells from four other species of turtle ranging from a desert tortoise to a loggerhead sea turtle resulted in specific and exclusive hybridization to chromosome 1 in all five species, Previous observations of conservation in the giemsa band ing pattern and chromosome morphology and number among turtles are thus ext ended to the DNA sequence level, revealing a cytogenetic stability of chrom osome 1 in these turtles during the past 66-144 million years. This contras ts with the situation for various hominoid species where, in many instances , extensive chromosomal rearrangements have been reported in one third of t hat time period. Our probe, which was prepared by microdissecting whole chr omosomes from embryonic T. scripta fibroblasts and amplifying using DOP-PCR , is the first report of a whole-chromosome FISH probe for any reptile. Cop yright (C) 2001 S. Karger AG, Basel.