In contrast to coding sequences, microsatellites are less well conserved between different species. However, the use of heterologous PCR primers in related mammalian groups is possible (Buchanan and Crawford 1992; Moore et al. 1991;Swarbrick et al. 1992). We have observed that 70-80% of microsatellite sequences isolated from cattle can be specifically amplified in other Bovidae species (such as goat and sheep, and several wild species). However, none of our bovine microsatellites could be amplified from horse DNA (unpublished results). These results suggest that mapping data obtained in Bos taurus could be useful in the study of other species of economic interest, such as Capra hircus or Ovis aries.
Although 14 syntenic groups among 30 are not yet assigned to a specific chromosome in cattle, the use of panels of somatic cell hybrids even without prior knowledge on their karyotype has proved a very valuable tool for establishing syntenic relationships (Zhang et al. 1992; Zhang and Womack 1992). In this paper, four bovine microsatellites (two of which have not been previously reported) are assigned to bovine U6 (Chr 3) by use of a hamster-bovine panel of somatic cell hybrids, and an order is proposed for the four loci. A hamster-sheep panel allowed us to check whether the synteny was conserved between the two species.
Bovine microsatellites were obtained by screening of a Sau3A size-selected bovine genomic library with two oligonucleotidic probes, (TG)10 and (TC)10, as described by Vaiman and coworkers (1992). Thirty-six hamster/bovine somatic cell hybrids were previously obtained by Heuertz (Heuertz and Hors-Cayla 1978). Definition of reference synteny groups or chromosomes in the panel was obtained with loci mapped on these hybrids so that only one pattern was retained to describe each cluster. All microsatellite patterns were then compared with each other and with the reference cluster. Forty microsatellites were tested on this panel, and we could show that four of them [INRA003,
For all text and figures, INRAOXX is equivalent to INRAXX.