Development and assignment of bovine-specific PCR systems for the Texas nomenclature marker genes and isolation of homologous BAC probes

In 1996, Popescu et al. published the Texas standard nomenclature of the bo vine karyotype in which 31 marker genes, already mapped in man, were chosen to permit unambiguous identification and numbering of each bovine chromoso me. However, specific PCR systems were not available for each marker gene t hus preventing the assignment of part of these markers by somatic cell hybr id analysis. In addition, some difficulties remained with the nomenclature of BTA25, BTA27 and BTA29. In this work, specific PCR systems were develope d for each of the marker genes except VIL1 (see results), from either exist ing bovine or human sequences, and a bovine BAC library was screened to obt ain the corresponding BAC clones. These PCR systems were used successfully to confirm the assignment of each marker gene (except for LDHA, see results ) by analysis on the INRA hamster-bovine somatic cell hybrid panel. The dif ficulties observed for LDHA and VIL1 are probably due to the fact that thes e genes belong to large gene families and therefore suggest that they may n ot be the most appropriate markers for a standardisation effort. This panel of BACs is available to the scientific community and has served as a basis for the establishment of a revised standard nomenclature of bovine chromos omes.