| Research Abstract |
The construction of comparative chromosome map is one of useful approaches for identifiing chromosome rearrangements and chromosomal homology between different animal species.
In this study, we constructed comparative maps of Syrian hamster and Chinese hamster to mouse and rat by the direct R-banding fluorescence in situ hybridization (FISH) using mouse and rat cDNA clones. We identified twenty-six and thirteen chromosomal regions with conserved linkage homology to mouse in Syrian and Chinese hamsters, respectively. In comparison between mouse-rat and mouse-Syrian hamster comparative chromosome maps, our results indicated a possibility that there are more chromosome rearrangements between mouse and Syrian hamster chromosomes than between mouse and rat chromosomes.
To estimate the process of X chromosome rearrangements in Rodentia animals, we constructed cytogenetic maps of mouse (M.m. domesticus), rat, Syrian hamster, Chinese hamster and Indian spiny mouse (M.platythrix) X chromosomes with twenty-six functional genes, which have been mapped on human X chromosome. The comparison of the gene orders indicated the presence of four chromosome segments with conserved linkage homology between mouse and rat X chromosomes. However, the gene orders were the same among rat, Syrian hamster, Chinese hamster and Indian spiny mouse X chromosomes with the exception of two genes. The gene orders in these species were similar to that of human X chromosome. These results suggested that numerous X chromosome rearrangements accumulated in mouse, and that Indian spiny mouse X chromosome is closely related to the ancestral mammalian X chromosome. We found several chromosome segments with different gene orders in Suncus murinus compared with mouse and human X chromosomes.
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