TY - JOUR
T1 - Gene-centromere mapping of bovine DYA, DRB3, and PRL using secondary oocytes and first polar bodies
T2 - Evidence for four-strand double crossovers between DYA and DRB3
AU - Jarrell, Vickie L.
AU - Lewin, Harris A.
AU - Da, Yang
AU - Wheeler, Matthew B.
PY - 1995/5/1
Y1 - 1995/5/1
N2 - A genetic map consisting of three loci anchored at the centromere of bovine chromosome 23 was constructed by genotyping secondary oocytes (SO) and first polar bodies (PB1) using a polymerase chain reaction (PCR)-based approach. Primary oocytes arrested in prophase of meiosis I were stimulated in vitro to resume division and extrude PB1. Sixty SO and their matched PB1 were collected from 14 cows by micromanipulation, subjected to amplification of the whole genome by primer extension preamplification, and genotyped independently for the linked genes PRL, DRB3, and DYA by PCR-RFLP analysis. Single-locus analysis of gene-centromere recombination rates were θcen-DYA = 0.042, θcen-DRB3 = 0.113, and θcen-PRL =0.166. The most likely order is cen-DYA-DRB3-PRL. Analysis of typing data from 3 cows revealed three meiotic divisions consistent with “linkage phase exchange” between DYA and DRB3 or PRL. One of the three linkage phase exchanges was confirmed by complementary genotypes in a matched secondary oocyte-first polar body pair. Such linkage phase exchanges could result from four-strand double crossovers between homologous chromosomes. Because all four gametes produced by four-strand double crossovers will be recombinant, more frequent occurrence of such events in females may explain the sexual dimorphism in genetic maps. Alternatively, four-strand crossovers could represent a type of recombination hotspot between DYA and DRB3, suggesting a mechanism for the high recombination frequency (15%) between these two class II genes of the bovine major histocompatibility complex.
AB - A genetic map consisting of three loci anchored at the centromere of bovine chromosome 23 was constructed by genotyping secondary oocytes (SO) and first polar bodies (PB1) using a polymerase chain reaction (PCR)-based approach. Primary oocytes arrested in prophase of meiosis I were stimulated in vitro to resume division and extrude PB1. Sixty SO and their matched PB1 were collected from 14 cows by micromanipulation, subjected to amplification of the whole genome by primer extension preamplification, and genotyped independently for the linked genes PRL, DRB3, and DYA by PCR-RFLP analysis. Single-locus analysis of gene-centromere recombination rates were θcen-DYA = 0.042, θcen-DRB3 = 0.113, and θcen-PRL =0.166. The most likely order is cen-DYA-DRB3-PRL. Analysis of typing data from 3 cows revealed three meiotic divisions consistent with “linkage phase exchange” between DYA and DRB3 or PRL. One of the three linkage phase exchanges was confirmed by complementary genotypes in a matched secondary oocyte-first polar body pair. Such linkage phase exchanges could result from four-strand double crossovers between homologous chromosomes. Because all four gametes produced by four-strand double crossovers will be recombinant, more frequent occurrence of such events in females may explain the sexual dimorphism in genetic maps. Alternatively, four-strand crossovers could represent a type of recombination hotspot between DYA and DRB3, suggesting a mechanism for the high recombination frequency (15%) between these two class II genes of the bovine major histocompatibility complex.
UR - http://www.scopus.com/inward/record.url?scp=0029023608&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029023608&partnerID=8YFLogxK
U2 - 10.1006/geno.1995.1005
DO - 10.1006/geno.1995.1005
M3 - Article
C2 - 7665182
AN - SCOPUS:0029023608
SN - 0888-7543
VL - 27
SP - 33
EP - 39
JO - Genomics
JF - Genomics
IS - 1
ER -