The species and chromosomal distribution of the centromeric α-satellite I sequence from sheep in the tribe Caprini and other Bovidae

Abstract

The evolution of chromosomes in species in the family Bovidae includes fusion and fission of chromosome arms (giving different numbers of acrocentric and metacentric chromosomes with a relatively conserved total number of arms) and evolution in both DNA sequence and copy number of the pericentromeric α-satellite I repetitive DNA sequence. Here, a probe representing the sheep α-satellite I sequence was isolated and hybridized to genomic DNA digests and metaphase chromosomes from various Bovidae species. The probe was highly homologous to the centromeric sequence in all species in the tribe Caprini, including sheep (Ovis aries), goat (Capra hircus) and the aoudad or Barbary sheep (Amnotragus lervia), but showed no detectable hybridization to the α-satellite I sequence present in the tribe Bovini and at most very weak to species in the tribes Hippotragini, Alcelaphini or Aepycerotini. The sex chromosomes of sheep, goat and aoudad did not contain detectable α-satellite I sequence; in sheep, one of the three metacentric autosomal chromosomes does not carry the sequence, while in aoudad, it is essentially absent in three large autosomal pairs as well as the large metacentric chromosome pair. The satellite probes can be used as robust chromosome and karyotype markers of evolution among tribes and increase the resolution of the evolutionary tree at the base of the Artiodactyla.

Phylogenetic relationships and the primitive X chromosome inferred from chromosomal and satellite DNA analysis in Bovidae

“…For in situ hybridization on chromosomes and extended chromatin fibres, a satellite I sheep clone pOaKB9 (Chaves et al 2000a(Chaves et al , 2003b) and a satellite I cattle clone, (pBtKB5, GenBank AJ293510, Chaves et al 2000bChaves et al , 2003a labelled Table 1. In situ hybridization patterns with probes sheep satellite I DNA (pOaKB9) and cattle satellite I DNA (pBtKB5) in all chromosome preparations of the 15 Bovidae species analysed.…”

“…Both Modi et al (1993Modi et al ( , 1996 and Chaves et al (2000a) observed different satellite DNA in situ hybridization patterns within a small number of tribes in the Bovidae family, and we considered that the sequences had potential as phylogenetic markers to increase the resolution of the evolutionary tree at the base of the Artiodactyla (Chaves et al 2000a). Here we aimed to analyse the presence and distribution of satellites to address evolutionary and phylogenetic questions with respect to the X chromosome (and its primitive state), karyotype, species and tribal evolution.…”

Chromosomal evolution and phylogenetic analyses in Tayassu pecari and Pecari tajacu (Tayassuidae): tales from constitutive heterochromatin

“…The ubiquity and persis-tence of heterochromatin in these genomes suggest that this distinctive genomic component has an adaptive value, be-sides being considered a genomic compartment carrying out important functions with an unconventional structural and functional basis (Dimitri et al 2004). Among other repetitive sequences, this genomic fraction comprises satellite DNAs that usually reside in the centromeric regions of chromo-somes (Chaves et al 2000). Identification of CH and its size differences is made feasible by the simple but extremely useful C-banding technique.…”

Centromere Evolution: Digging into Mammalian Primary Constriction

“…1). The sheep satellite I DNA (the 1.714 family) has a repeat unit of 820 bp and, as the bovine satellites, constitutes the centromeric heterochromatin of all autosomes, but not of the sex chromosomes (Buckland, 1983;Burkin et al, 1996;Chaves et al, 2000;Chaves et al, 2005). However, the amount and organization of satellite I DNA differ among the autosomes, with a lower amount at the centromeres of the biarmed chromosomes 1, 2, and 3, particularly of chromosome 1 (Burkin et al, 1996;D'Aiuto et al, 1997).…”