Sokoine University of Agriculture

The origin of an unusual sex chromosome constitution in Acomys sp. (Rodentia, Muridae) from Tanzania

Show simple item record Castiglia, Riccardo Makundi, Rhodes H. Corti, Marco 2016-12-02T10:04:36Z 2016-12-02T10:04:36Z 2007
dc.description.abstract This paper describes a case which presents an evident variation from the ‘‘standard’’ XX/XY sex chromosomal constitution in a rodent, Acomys sp. This species known to be found in three localities of East Africa has only recently been separated from A. spinosissimus, its closest relative. In our study, five specimens of Acomys sp. and eight specimens of A. spinosissimus were live-trapped in five localities. Comparisons between the two taxa assed by G- banding show a complete homology in the chromosomal shape and banding pattern for 29 pairs of chromosomes corresponding to the complete autosomal set of A. spinosissimus. However, while all the A. spinosissimus analysed have 2n = 60 and a XY-XX system, in Acomys sp. males and females constitute mosaics for sex chromosomes in the bone marrow cells. Females (2n = 59, 60) have an excess (97%) of aneuploid cells with one single giant X chromosome, and males (2n = 60, 61) show X0/XY cells occurring in somatic tissues and XY cells in the germinal lineage. In addition, an odd heterochromatic submetacentric chromosome was identified in all the cells examined in two males and a female of Acomys sp. Since this chromosome was not related to sex determination and it is not present in all the analysed specimens, it can be considered as a B chromosome. Finally, the in situ fluorescence hybridisation (FISH) with telomeric probes showed a very intense interstitial telomeric signal (ITS) at the medial part on the long heterochromatic arm of the X chromosome. This could be due to recent chromosomal rearrangement. en_US
dc.language.iso en en_US
dc.publisher Springer Science+Business Media B.V. 2006 en_US
dc.subject Acomys spinosissimus en_US
dc.subject African rodent en_US
dc.subject B chromosome en_US
dc.subject Cytotaxonomy en_US
dc.subject Mosaicism en_US
dc.subject Sex chromosome en_US
dc.subject Telomeric sequences en_US
dc.subject In situ fluorescence hybridisation en_US
dc.title The origin of an unusual sex chromosome constitution in Acomys sp. (Rodentia, Muridae) from Tanzania en_US
dc.type Article en_US

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