Localization by FISH of the 31 Texas nomenclature type I markers to both Q- and R-banded bovine chromosomes

Abstract

A series of 31 marker genes (one per chromosome) were localized precisely to both Q- and R-banded bovine chromosomes by fluorescence in situ hybridization (FISH), as a contribution to the revised chromosome nomenclature of the three major domestic bovidae (cattle, sheep and goat). All marker genes except one (LDHA) are taken from the Texas Nomenclature of the cattle karyotype published in 1996. Homologous probes for each marker gene were obtained by screening a bovine BAC library by PCR with specific primer pairs. After labeling with biotin, each probe preparation was divided into two fractions and hybridized to bovine chromosomes identified either by Q or R banding. Clear signals and good quality band patterns were observed in all cases. Results of the two series of hybridizations are totally concordant both for Q and R band chromosome numbering and precise band localization. This work permits an unambiguous correlation between the Q/G- and R-banded 31 bovine chromosomes, including chromosomes 25, 27 and 29 which remained unresolved in the Texas Nomenclature (1996). Hybridization of the chromosome 29 marker gene to metaphase spreads from a 1;29 Robertsonian translocation bull carrier showed a positive signal on the short arm of this rearranged chromosome, confirming that the numbering of this long-known translocation in cattle is correct when referring to the Texas Nomenclature (1996). Taking into account that cattle, goat and sheep have very similar banded karyotypes, the data presented here will help to establish a definite and complete reference chromosome nomenclature for these species.

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

“…The panel is available upon request to the entire scientific community and has served as a basis for the establishment of a revised standard nomenclature [8] based on homologous probes.…”

International System for Chromosome Nomenclature of Domestic Bovids (ISCNDB 2000)

“…This was achieved by hybridizing each of the 31 Texas nomenclature chromosome specific markers on both Q-and R-banded bovine chromosome preparations (Hayes et al, 2000). Based on this essential data, Q-, G-and R-banded bovine karyotypes were arranged according to a common nomenclature.…”

Construction and characterization of a bovine BAC library with four genome-equivalent coverage

“…Only one microsatellite was not found in the library. The library was also successfully screened for the 31 marker genes of the Texas standard nomenclature of the bovine karyotype [4], providing an accurate set of BAC clones which were used to resolve chromosome identification problems [4,6]. Fluorescence in situ hybridisation was performed as described [6] for over 50 BAC clones: none of the clones was chimeric.…”