Families of tandemly repeated DNA elements from horse: cloning, nucleotide sequence, and organization

Abstract

DNA repeats, revealed initially by digestion of horse DNA with restriction enzymes, were cloned and characterized by cross-hybridization studies and nucleotide sequencing. The Sau-like family of tandem repeats contained two classes of repetitive elements with unit repeats of about 80 bp that shared no sequence similarity. Both unit repeats were present, frequently in tandem, in cloned segments of horse DNA of less than 600 bp. Evidence is presented, based on their ladderlike patterns of hybridization to horse DNA and their high level of similarity to published sequences of satellites from equine DNA, suggesting that they are centromerically located in the horse genome. The Sau-like tandem repeat families were specific to Equidae. Another class of repeats, GATA-like elements, which did not appear to have a centromeric distribution, was also cloned and sequenced.Key words: Equidae, Equus caballus, tandem DNA repeats, GATA-like repeats, Sau3AI repeats.