Gallagher D S, Davis S K, De Donato M, Burzlaff J D, Womack J E, Taylor J F, Kumamoto A T
Department of Animal Science, Texas A&M University, College Station 77843, USA.
Chromosome Res. 1998 Nov;6(7):505-13. doi: 10.1023/a:1009268917856.
A combination of chromosomal banding and fluorescence in situ hybridization (FISH) was used to characterize the karyotype of Boselaphus tragocamelus (nilgai) relative to the domestic cattle standard karyotype. G-, Q- and C-band karyotypes of nilgai are presented, and the chromosomal complement of nilgai is determined to be 2n=46 (female FN=60, male FN=59; NAA=56), consistent with previous reports for the species. Comparisons with cattle identified extensive monobrachial homologies with some noteworthy exceptions. Chromosome 25 is centrically fused to 24, and chromosome 16 is acrocentric. Both appear to have additional pericentromeric material not seen in the equivalent cattle acrocentrics. This pericentromeric chromatin may be the result of de novo additions or translocation of pericentromeric material from chromosome 6, which is shown to be centrically fused to 13 but is only about two-thirds the length of cattle 6. Comparisons with cattle demonstrated that nilgai chromosome 17 has undergone a paracentric inversion and that chromosome 20 has two blocks of interstitial constitutive heterochromatin. The identities of both chromosomes were confirmed by chromosomal FISH. Furthermore, chromosomal banding and FISH were used to determine that autosome 14 has been fused to the ancestral X and Y of nilgai to form compound neo-X and -Y chromosomes. Additional FISH analyses were conducted to confirm other proposed chromosome homologies and to identify nucleolar organizing regions within the nilgai complement.
采用染色体显带和荧光原位杂交（FISH）相结合的方法，相对于家牛标准核型对蓝牛羚的核型进行特征分析。展示了蓝牛羚的G带、Q带和C带核型，并确定蓝牛羚的染色体组成为2n = 46（雌性FN = 60，雄性FN = 59；NAA = 56），与该物种先前的报道一致。与牛的比较发现了广泛的单臂同源性，但也有一些值得注意的例外。25号染色体与24号染色体着丝粒融合，16号染色体为近端着丝粒染色体。两者似乎都有额外的着丝粒周围物质，这在家牛相应的近端着丝粒染色体中未见。这种着丝粒周围染色质可能是着丝粒周围物质从头添加或从6号染色体易位的结果，6号染色体显示与13号染色体着丝粒融合，但长度仅约为家牛6号染色体的三分之二。与牛的比较表明，蓝牛羚17号染色体发生了臂内倒位，20号染色体有两个中间组成型异染色质区。通过染色体FISH证实了这两条染色体的身份。此外，利用染色体显带和FISH确定常染色体14已与蓝牛羚的祖先X和Y染色体融合，形成复合新X和新Y染色体。进行了额外的FISH分析，以确认其他提出的染色体同源性，并确定蓝牛羚染色体组内的核仁组织区。
