Molecular insights into X;BTA5 chromosome rearrangements in the tribe Antilopini (Bovidae)

Abstract

For a clade that includes Antilope, Gazella,Nanger and Eudorcas (Antilopinae), X;BTA5 translocation is a synapomorphy. Using a combination of fluorescence in situ hybridization (FISH) probes and polymerase chain reaction techniques, we provide (i) the first insight into the X;BTA5 architecture which differs in the species under study: Antilope cervicapra (genus Antilope), Gazella leptoceros (genus Gazella) and Nanger dama ruficollis (genus Nanger), (ii) determination of interstitial satellite DNA at the X;BTA5 junctions, and (iii) determination of repetitive sequences occupying constitutive heterochromatin of Xp arms in the studied species. The distribution of 2 repetitive DNA families in the centromeric regions of all chromosomes has been investigated by FISH with probes representing satellite I and satellite II DNA in all studied species. In this context, we discuss a markedly smaller centromere in the BTA5 (Y2) unfused chromosomes in males in the XY1Y2 determining system in comparison with other acrocentrics. An analysis of karyotypic data described in current published studies revealed a disparity with the data determined by FISH. In this report, we document chromosomal fusions in the 3 species mentioned resulting from FISH with painting probes prepared from cattle (Bos taurus). The number and chromosomal location of nucleolus organizer regions were determined by FISH. In the present study, we emphasize the importance of chromosomal rearrangement verification, particularly, if they are used for phylogenetic analysis.