title: Tracking chromosome evolution in southern African gerbils using flow-sorted chromosome paints.
abstract: Desmodillus and Gerbilliscus (formerly Tatera) comprise a monophyletic group of gerbils (subfamily Gerbillinae) which last shared an ancestor approximately 8 million years ago; diploid chromosome number variation among the species ranges from 2n = 36 to 2n = 50. In an attempt to shed more light on chromosome evolution and speciation in these rodents, we compared the karyotypes of 7 species, representing 3 genera, based on homology data revealed by chromosome painting with probes derived from flow-sorted chromosomes of the hairy footed gerbil, Gerbillurus paeba (2n = 36). The fluorescent in situ hybridization data revealed remarkable genome conservation: these species share a high proportion of conserved chromosomes, and differences are due to 10 Robertsonian (Rb) rearrangements (3 autapomorphies, 3 synapomorphies and 4 hemiplasies/homoplasies). Our data suggest that chromosome evolution in Desmodillus occurred at a rate of ~1.25 rearrangements per million years (Myr), and that the rate among Gerbilliscus over a time period spanning 8 Myr is also ~1.25 rearrangements/Myr. The recently diverged Gerbillurus (G. tytonis and G. paeba) share an identical karyotype, while Gerbilliscus kempi, G. afra and G. leucogaster differ by 6 Rb rearrangements (a rate of ~1 rearrangement/Myr). Thus, our data suggests a very slow rate of chromosomal evolution in Southern African gerbils.
authors: Evolutionary Genomics Group, Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa.
authors: L I
authors: LI
authors: Knight
authors: B L
authors: BL
authors: Ng
authors: W
authors: W
authors: Cheng
authors: B
authors: B
authors: Fu
authors: F
authors: F
authors: Yang
authors: R V
authors: RV
authors: Rambau
mesh_terms: D000818:Animals; D002871:Chromosome Banding; D007446:Chromosome Inversion; D020223:Chromosome Painting / Q000379:methods*; D033481:Chromosomes, Mammalian / Q000235:genetics*; D015342:DNA Probes / Q000235:genetics; D019143:Evolution, Molecular; D049810:Genetic Speciation; D005849:Gerbillinae / Q000145:classification / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D059785:Karyotype; D008297:Male; D010802:Phylogeny; D012680:Sensitivity and Specificity; D013045:Species Specificity; D013997:Time Factors
chemical_list: D015342:DNA Probes
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