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United States Department of Agriculture

Agricultural Research Service

Research Project: ENHANCING GENETIC MERIT OF DAIRY CATTLE THROUGH GENOME SELECTION AND ANALYSIS Title: Mapping Quantitative Trait Loci Associated with Parasitic Infection Using 50k Snp Chip in Angus Breed

item ,
item Van Tassell, Curtis
item Sonstegard, Tad
item Matukumalli, Lakshmi - GEORGE MASON
item Schroeder, Steven
item Gasbarre, Louis

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2008
Publication Date: April 15, 2008
Citation: Silva, M.V., Van Tassell, C.P., Sonstegard, T.S., Matukumalli, L.K., Schroeder, S.G., Gasbarre, L.C. 2008. MAPPING QUANTITATIVE TRAIT LOCI ASSOCIATED WITH PARASITIC INFECTION USING 50K SNP CHIP IN ANGUS BREED. BARC Poster Day.

Technical Abstract: QTL for parasite indicator traits in cattle are ideal targets for study of marker assisted selection; however the phenotypic data and available resource populations were not optimal for reliable QTL identification. Fecal egg count (FEC) values, which are used to measure resistance to nematodes, are not “normally” distributed and logarithmic transformations fail to properly normalize this data in most cases. FEC data recorded for 410 animals between 1992 and 2003 from the BARC Angus herd were transformed using log and an extension of the Box-Cox transformation to approach normality. In preliminary analysis to estimate the position and variance components of the QTL, 221 microsatellites markers were genotyped across 29 chromosomes and QTL detection was done using QxPak. QTL for Box-Cox transformed FEC was on chromosome 6 at 5% chromosome-wise significant P-value. For raw and log transformation FEC data, no QTL were found. These results indicate that after transforming data by the Box-Cox procedure the QTL mapping were more exact. The results of this analysis will be compared to those done using an association analysis with genotypes from 49,559 SNPs genotypes generated from the Bovine50K SNP chip. Supported by USDA ARS CRIS Project No. 1265-31000-098-00D.

Last Modified: 4/21/2015