A male bovine linkage map for the ADR granddaughter design

The aim of this paper is to present the construction of a male generic link age map as a result of the bovine genome mapping project, which is a common effort of the German cattle breeding federation (ADR), four animal breedin g institutes, three blood group laboratories and two animal data and breedi ng value evaluation centres. In total 20 grandsires with 1074 sires were pr ovided from the German cattle population as reference families, 16 of these paternal half-sib groups are German Holstein families (DH), three are Germ an Simmental (ST) families, and one is a Brown Swiss family (BS). Of 265 ma rkers included in the linkage map, 248 were microsatellite markers, five we re bovine blood group systems, eight SSCP markers and four proteins and enz ymes. More than 239 000 genotypes resulted from typing the offspring for th e respective markers and these were used for the construction of the map. O n average 478 informative meioses were provided from each marker of the map . The summarized map length over all chromosomes was 3135.1 cM with an aver age interval size of 13.34 cM. About 17, 35.7 and 79.1% of the map interval s showed a maximum genetic distance between the adjacent markers of 5, 10 a nd 20 cM, respectively. The number of loci ranged from two (pseudoautosomal region of the sex chromosome, BTAY) to 15 (BTA23) with an average of 8.8 m arkers per chromosome. Comparing the length of the chromosomes shows variat ion from 49.6 cM for BTA26 to 190.5 cM for BTA1 with a mean of 107.7 cM for all autosomes of the genetic linkage map. It was possible to identify chro mosomal discrepancies in locus order and map intervals by comparison with o ther published maps. The map provided sufficient marker density to serve as a useful tool for a scan of segregating quantitative trait loci.