title: Unusually high recombination rate detected in the sex locus region of the honey bee (Apis mellifera).
abstract: Sex determination in Hymenoptera is controlled by haplo-diploidy in which unfertilized eggs develop into fertile haploid males. A single sex determination locus with several complementary alleles was proposed for Hymenoptera [so-called complementary sex determination (CSD)]. Heterozygotes at the sex determination locus are normal, fertile females, whereas diploid zygotes that are homozygous develop into sterile males. This results in a strong heterozygote advantage, and the sex locus exhibits extreme polymorphism maintained by overdominant selection. We characterized the sex-determining region by genetic linkage and physical mapping analyses. Detailed linkage and physical mapping studies showed that the recombination rate is <44 kb/cM in the sex-determining region. Comparing genetic map distance along the linkage group III in three crosses revealed a large marker gap in the sex-determining region, suggesting that the recombination rate is high. We suggest that a "hotspot" for recombination has resulted here because of selection for combining favorable genotypes, and perhaps as a result of selection against deleterious mutations. The mapping data, based on long-range restriction mapping, suggest that the Q DNA-marker is within 20,000 bp of the sex locus, which should accelerate molecular analyses.
authors.affiliation: Martin-Luther-Universität Halle/Wittenberg, Institut für Zoologie, Molekulare Okologie, 06099 Halle, Germany. mbeye@ucdavis.edu
authors.forename: M
authors.initials: M
authors.lastname: Beye
authors.forename: G J
authors.initials: GJ
authors.lastname: Hunt
authors.forename: R E
authors.initials: RE
authors.lastname: Page
authors.forename: M K
authors.initials: MK
authors.lastname: Fondrk
authors.forename: L
authors.initials: L
authors.lastname: Grohmann
authors.forename: R F
authors.initials: RF
authors.lastname: Moritz
mesh_terms: D000818:Animals; D001483:Base Sequence; D001516:Bees / Q000235:genetics*; D017931:DNA Primers; D005260:Female; D008040:Genetic Linkage; D005838:Genotype; D008297:Male; D011995:Recombination, Genetic; D019849:Sex Determination Processes
chemical_list: D017931:DNA Primers