Genetics. Published Articles Ahead of Print: August 24, 2007, Copyright © 2007
doi:10.1534/genetics.107.077784


A more recent version of this article appeared on October 1, 2007.


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The number of loci that affect milk production traits in dairy cattle

1 DPI Victoria

* To whom correspondence should be addressed. E-mail: amanda.chamberlain{at}dpi.vic.gov.au.

Submitted on June 18, 2007
Revised on July 16, 2007
Accepted on 16 July 2007


Abstract

We have used the results of an experiment mapping quantitative trait loci (QTL) affecting milk yield and composition to estimate the total number of QTL affecting these traits. We did this by estimating the number of segregating QTL within a half-sib daughter design using logic similar to that used to estimate the "false discovery rate" (FDR). In a half-sib daughter design with 6 sire families we estimate that the average sire was heterozygous for approximately five QTL per trait. Also, in most cases only one sire was heterozygous for any one QTL, therefore at least 30 QTL were likely to be segregating for these milk production traits in this Holstein population.

Key Words: false discovery rate, gene mapping, milk production, quantitative trait, quantitative trait loci