Issue |
Genet. Sel. Evol.
Volume 36, Number 2, March-April 2004
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Page(s) | 163 - 190 | |
DOI | https://doi.org/10.1051/gse:2003057 |
DOI: 10.1051/gse:2003057
Quantitative trait loci mapping in dairy cattle: review and meta-analysis
Mehar S. Khatkar, Peter C. Thomson, Imke Tammen and Herman W. RaadsmaCentre for Advanced Technologies in Animal Genetics and Reproduction (ReproGen), and Co-operative Research Centre for Innovative Dairy Products, Faculty of Veterinary Science, University of Sydney, PMB 3, Camden NSW 2570, Australia
(Received 4 July 2003; accepted 29 October 2003)
Abstract
From an extensive review of public domain information on dairy cattle
quantitative trait loci (QTL), we have prepared a draft online QTL map for
dairy production traits. Most publications (45 out of 55 reviewed) reported
QTL for the major milk production traits (milk, fat and protein yield, and
fat and protein concentration (%)) and somatic cell score. Relatively few
QTL studies have been reported for more complex traits such as mastitis,
fertility and health. The collated QTL map shows some chromosomal regions
with a high density of QTL, as well as a substantial number of QTL at single
chromosomal locations. To extract the most information from these published
records, a meta-analysis was conducted to obtain consensus on QTL location
and allelic substitution effect of these QTL. This required modification and
development of statistical methodologies. The meta-analysis indicated a
number of consensus regions, the most striking being two distinct regions
affecting milk yield on chromosome 6 at 49 cM and 87 cM explaining 4.2 and
3.6 percent of the genetic variance of milk yield, respectively. The first
of these regions (near marker BM143) affects five separate milk production
traits (protein yield, protein percent, fat yield, fat percent, as well as
milk yield).
Key words: quantitative trait loci / dairy cattle / review / meta-analysis
Correspondence and reprints: Peter C. Thomson PeterT@camden.usyd.edu.au
© INRA, EDP Sciences 2004