Constitutive heterochromatin variation in two species of rattus with apparently similar karyotypes |
| |
Authors: | T Sharma I K Gadi |
| |
Institution: | (1) Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, 221005 Varanasi, India;(2) Present address: Life Science Centre, The University of North Bengal, P.O. North Bengal University, Distr. Darjeeling, India |
| |
Abstract: | Rattus blanfordi and R. cutchicus medius both have a chromosome complement of 2n=36 and all chromosomes except the submetacentric Y of R. blanfordi are acrocentric. The apparently similar karyotypes of the two species, however, show variations in the nature and quantity of C-band-positive constitutive heterochromatin (C-heterochromatin) as revealed by C- and G-banding and Hoechst 33258 fluorescence. R. blanfordi with large-sized X and Y chromosomes and conspicuously larger centromeric heterochromatin in all the autosomes as compared to that of R. cutchicus medius has much more C-heterochromatin in its genome than the latter. The variation in the quantity of C-heterochromatin has been accomplished without altering the morphology of the acrocentric chromosomes unlike other mammals in which variations have been reported to result generally in the addition or deletion of a totally heterochromatic second arm. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|