Comparative cytogenetic mapping reveals chromosome rearrangements between the X chromosomes of two closely related mammalian species (cattle and goats)

Abstract

Cytogenetic localization of 24 BACs containing type I (genes and ESTs) and type II (microsatellites) markers were used to construct cytogenetic maps of caprine (CHI) and bovine (BTA) X chromosomes. Comparison of these two maps revealed that the distal region of the goat X long arm (CHI Xq38→q42) was located inside the bovine X chromosome, between PGK1 (BTA Xq25) and DVEPC137 (BTA Xq12). The marker order was globally conserved without any pericentric inversion, as previously postulated in the literature. The caprine centromere was found between DVEPC053 and DVEPC102 (belonging to the same band in the bovine X: BTA Xq41), whereas the bovine centromere was between DVEPC076 and DVEPC132, belonging to the same region of the caprine X chromosome (CHI Xq31→q33). The pseudoautosomal region was situated at the tip of the bovine X long arm and on the tiny short arm of the caprine X chromosome. In the non-pseudoautosomal (NPA) region, the synteny of coding sequences was well conserved between the human species and the two ruminant species, but the gene order was dramatically divergent. It is suggested that the 24 BACs of this study could constitute a new tool to measure phylogenetic distances between different mammalian species by comparing chromosome rearrangements inside the NPA region of the X.

Comparative Analysis (Hippotragini versus Caprini, Bovidae) of X-Chromosome's Constitutive Heterochromatin by in situ Restriction Endonuclease Digestion: X-Chromosome Constitutive Heterochromatin Evolution

“…These results are in accordance with previous ones, which described CH addition or elimination, during the Bovidae X-chromosome rearrangements (e.g. centromeric transpositions) (Piumi et al, 1998;Robinson et al, 1998;Gallagher et al, 1999;Iannuzzi et al, 2000). However, the data cited before was obtained with the comparison between diff erent morphological X-chromosomes (metacentric, submetacentric and acrocentric) where X-chromosome rearrangements are obvious, and some of that rearrangements were consistently confirmed with microdissected paints or BAC probes.…”

“…Several studies have been done to delineate the structural rearrangements that characterized the evolution of bovid X-chromosome and to determine the primitive and ancestral condition of Bovidae X-chromosome. These studies include Gand C-banding comparisons, in situ hybridizations with X paint probes and bacterial artificial chromosomes (BAC) clones to localize the homologous regions between the X-chromosomes of several species (Hayes, Petit & Dutrillaux, 1991;Kaftanovskaya & Serov,1994;Robinson et al, 1997;Piumi et al, 1998;Iannuzzi et al, 2000). A substantial proportion of the higher eukaryote genome consists of constitutive heterochromatin (CH).…”

An Enhanced Linkage Map of the Sheep Genome Comprising More Than 1000 Loci

“…It seems more likely that the ancestor of OAR1 split in separate places to generate chromosomes 1 and 3 of cattle and goat, than that the ancestral chromosomes for CHI/BTA 1 and 3 would have fused to form OAR 1, and that the region containing the THH gene would then have moved from BTA 3 to 1. The findings in this study extend those of Galloway and colleagues (1996) and suggest that the organization of the sheep X chromosome is more like that of the goat X chromosome than that of the cattle X chromosome (Ponce de Leon et al 1996;Hassanane et al 1998;Piumi et al 1998). Overall, the cattle X chromosome map appears inverted relative to the sheep and goat maps, with the pseudoautosomal region of sheep and goat X chromosomes being found at the tip of the short arm whereas that of cattle is found at the tip of the long arm.…”

“…Overall, the cattle X chromosome map appears inverted relative to the sheep and goat maps, with the pseudoautosomal region of sheep and goat X chromosomes being found at the tip of the short arm whereas that of cattle is found at the tip of the long arm. Other differences between ruminant X chromosomes include the relative positions of the centromeres, and the rearrangement of the bovine Xp24-Xq12 and Xq21-Xq24 regions in goats (Piumi et al 1998). Comparison of the ovine and bovine X chromosome linkage maps reveals that the segment between \BMS1820 (BTA Xq1-Xq2; Sonstegard et al 1997) and \BMS1008 (BTA Xp11; Sonstegard et al 1997) has moved from an interstitial position within the bovine X chromosome to the bottom of the sheep X chromosome.…”

Comparative Gene Mapping: A Fine-Scale Survey of Chromosome Rearrangements between Ruminants and Humans

“…The assumption of wide genomic interspecific similarity between the three main domestic species of ruminants is now well substantiated, and is based upon banding homology (Evans et al 1973;ISCNDA1989 1990) and molecular evidences (Crawford et al 1995;Vaiman et al 1996;Barendse et al 1997;Kappes et al 1997). Separating the three centric fusions differentiating sheep chromosomes from those of goats and cattle, the major discrepancies are because of the wellknown 9-14 translocation differentiating Bovinae and Caprinae (Crawford et al 1995;Vaiman et al 1996) and to the X chromosomes (Ponce de Leon et al 1996;Piumi et al 1998). …”