Original Contributions Mammalian Genome 5, 84-90 (1994). 9 Springer-Verlag New York Inc. 1994 Characterization of 65 bovine microsatellites S.S. Moore, 1 K. Byrne, 1 K.T. Berger, 1 W. Barendse, 1 F. McCarthy, 1 J.E. Womack, 2 D.J.S. Hetzel ~ ICSIRO, Division of Tropical Animal Production, Molecular Animal Genetics Centre, Level 3, Gehrmann Laboratories, University of Queensland, Brisbane, Queensland 4072, Australia 2Texas Veterinary Medical Center, College of Veterinary Medicine, Texas A&M University, College Station, Texas 77643-4463, USA Received: 16 July 1993 / Accepted: 29 September 1993 Abstract. Microsatellites or simple sequence repeat (SSR) polymorphisms are used widely in the construction of link- age maps in many species. High levels of polymorphism coupled with the ease of analysis of the polymerase chain reaction (PCR) have resulted in this type of maker being one of the most widely used for genetic analysis. In this pa- per we describe 58 polymorphic bovine microsatellites that were isolated from insert size selected bovine ge- nomic libraries. Primer sequences, number of alleles, and heterozygosity levels in cattle reference families are re- ported. Chromosomal locations for 47 of these mi- crosatellites as well as for 7 previously described systems derived from entries in the Genbank or EMBL databases have been determined. The markers map to 24 syntenic or chromosomal locations. Polymorphic bovine microsatel- lites were estimated to occur, on average, every 320 kb, and there is no evidence of clustering in the genome. Thirty of the bovine-derived microsatellite systems gave specific and polymorphic products in sheep, adding to the number of useful markers in that species. Introduction Since first being described less than 5 years ago (Tautz 1989; Weber and May 1989; Litt and Luty 1989), mi- crosatellites have been adopted widely for use in linkage mapping studies to the point that they are now the favored polymorphic marker for this purpose. Complete linkage maps have been constructed with only this type of mark- er in species such as mouse and human (Love et al. 1990; Bowcock et al. 1993). The popularity of these markers stems from the high level of polymorphism found at many The nucteotide sequence data reported in this paper have been submit- ted to GenBank, and have been assigned the accession numbers U03784- U03841. Correspondence to: S.S. Moore microsatellite loci and the use of the polymerase chain re- action (PCR) for their analysis. This combines an easy-to- use technology with a minimal requirement for sample DNA, an important factor when DNA resources are finite. Dinucleotide repeats, in particular (dC-dA) n 9 (dG-dT) n, are very abundant in many mammalian species (Love et al. 1990; Moore et al. 1991; Beckman and Weber 1992), with no evidence of clustering on specific chromosomes, there- by enabling efficient coverage of the genome to be achieved (Stallings et al. 1991). As part of a project to construct a linkage map of the cow (Hetzel 1991; Barendse et al. 1993), we have isolat- ed and characterized a large number of dinucleotide mi- crosatellites ((dC-dA)n " (dG-dT)n) from size-selected bovine genomic libraries and from a commercially avail- able cosmid library. A linkage map will allow genes or Quantitative Trait Loci (QTL; Paterson et al. 1988) of eco- nomic importance in cattle to be located and characterized. It has been estimated that a minimum of 150-200 markers will be required for a map with 20cM resolution. Howev- er, if markers are isolated at random, the strategy becomes less efficient and more than 500 will be required to achieve a 99% complete map with this spacing (Lange and Boehnke 1982; Steele and Georges 1991). As part of the characterization of microsatellites, it is therefore important that the map position be determined. It is clear that, as more markers are mapped, nonrandom strategies will be required to fill any gaps remaining between markers. Cytogenetic analysis (Hediger et al. 1991a) as well as physical mapping studies with in situ techniques (Hediger et al. 1990, 1991b) have demonstrated a close similarity be- tween the bovine and ovine genomes. It has also been demonstrated that a large proportion of microsatellites can be amplified and are polymorphic in both species (Moore et al. 1991). Accordingly, microsatellites isolated from cattle are a useful source of microsatellites in sheep and visa versa. In addition, map positions in one species can be predicted from the location in the other.