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

The evolution of chromosomes in species in the family Bovidae includes fusi on and fission of chromosome arms (giving different numbers of acrocentric and metacentric chromosomes with a relatively conserved total number of arm s! and evolution in both DNA sequence and copy number of the pericentromeri c alpha -satellite I repetitive DNA sequence. Here, a probe representing th e sheep alpha -satellite I sequence was isolated and hybridized to genomic DNA. digests and metaphase chromosomes from various Bovidae species. The pr obe was highly homologous to the centromeric sequence in all species in the tribe Caprini, including sheep (Ovis aries), goat (Capra hircus and the ao udad or Barbary sheep (Amnotragus lervia). but showed no detectable hybridi zation to the alpha -satellite I sequence present in the tribe Bovini and a t most very weak to species in the tribes Hippotragini, Alcelaphini or Aepy cerotini. The sex chromosomes of sheep, goat and aoudad did not contain det ectable alpha -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 meta centric chromosome pair. The satellite probes can be used as robust chromos ome and karyotype markers of evolution among tribes and increase the resolu tion of the evolutionary tree at the base of the Artiodactyla. Copyright (C ) 2001 S. Karger AG, Basel.