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Title: QTL Mapping OF PARASITE RESISTANCE INDICATOR traits IN AN EXPERIMENTAL ANGUS POPULATION

Author
item KIM, EUI-SOO - US Department Of Agriculture (USDA)
item SONSTEGARD, TAD - US Department Of Agriculture (USDA)
item SILVA, MARCOS VINICIUS - Embrapa
item GASBARRE, LOUIS - Collaborator
item VAN TASSELL, CURTIS - US Department Of Agriculture (USDA)

Submitted to: Animal Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/2013
Publication Date: 12/5/2013
Citation: Kim, E., Sonstegard, T.S., Silva, M., Gasbarre, L.C., Van Tassell, C.P. 2013. QTL Mapping OF PARASITE RESISTANCE INDICATOR traits IN AN EXPERIMENTAL ANGUS POPULATION. Animal Genetics. DOI: 10.1111/age.12101.

Interpretive Summary: This report is the first to report the genome locations of host resistant affecting parasite indicator triats measured in a resource population of Angus cattle. The regions were mapped using older DNA marker technology at a much lower resolution of about 200 markers. The genetic map analysis to find the locations of these traits revealed the strongest effect was found on chromosome 6 in a region of the genome containing many genes involved in immune function and response. This report also showed the need to generate new tools to map effects at a higher resolution.

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. The QTL we identified needs to be validated in other populations.