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United States Department of Agriculture

Agricultural Research Service


item Freking, Brad
item De Gortari, M
item Crawford, A
item Dodds, K
item Kappes, Steven - Steve
item Keele, John
item Stone, Roger
item Leymaster, Kreg
item Beattie, Craig

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 6/10/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: A genetic map of Ovis aries (haploid N=27) was developed with 514 loci in 26 autosomal linkage groups spanning 3022.3 cM (sex-average) and 102.9 cM (female-specific) of the X chromosome. Data from two independent sheep reference populations were merged by genotyping common microsatellite (MS) markers across both pedigrees. The AgResearch International Mapping Flock (IMF) consisted of 9 three-generation full-sib pedigrees with a total of 100 progeny. The USDA reference population (MARC) consisted of 247 backcross progeny produced by mating 4 F1 rams (2 Suffolk x Romanov, 2 Rambouillet x Romanov) to 40 Romanov ewes. The mean number of informative meioses per marker was 197. Genomic conservation among Bovidae allowed the extensive use of MS developed in bovine (397/500 MS, 79.4%). Average autosomal heterozygosities of the IMF and MARC sires were 67.4, and 64.0%, respectively. Linkage groups were constructed using CRI-MAP version 2.4 software. Initial marker groups were based on significant (LOD>3.0) two-point linkages. Markers were then sorted by number of informative meioses and subsequently developed into the linear order which maximized the multipoint likelihood function. Individual linkage groups averaged 19 markers and 115.8 cM. The average interval between adjacent linked markers was 6.4 cM, with 55.5% of the intervals < 5 cM and only 3.8% of the intervals > 20 cM. Twenty of the 26 autosomes are oriented with respect to the centromere, either directly in sheep or indirectly through orientation on the homologous bovine chromosome. The current map based on MS is suitable for continued development of a high resolution map, initial detection of quantitative trait loci in resource populations, and development of a comparative linkage map with other bovid species.

Last Modified: 10/15/2017
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