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Journal of Cell and Animal Biology Vol. 1(3), 048-057, October, 2007
ISSN 1996-0867
© 2007 Academic Journals
Full Length Research Paper
Detection and mapping of
QTL on bovine chromosomes 2 and 5 segregating for live weight, average
daily gain and body measurements in Japanese black cattle
A. E. O. Malau-Aduli*1, T. Niibayashi3, T.
Kojima3, K. Oshima3, Y. Mizoguchi4 and
M. Komatsu2
1Animal Production and Genetics, School of Agricultural
Science, Faculty of Science, Engineering and Technology, University of
Tasmania, Private Bag 54 Hobart, Tasmania 7001, Australia.
2Department of Animal Breeding and Reproduction, National
Institute of Livestock and Grassland Science, Tsukuba, Ibaraki 305-0901,
Japan.
3Laboratory of Animal Breeding and Reproduction, Department
of Livestock and Grassland Science, National Agricultural Research
Centre for Western Region, Oda, Shimane 694-0013, Japan.
4Shirakawa Institute of Animal Genetics, Nishigo-nura,
Fukushima 961-8061, Japan.
*Corresponding author. E-mail:
Aduli.MalauAduli@utas.edu.au
Accepted 24 September, 2007
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Abstract |
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Bovine chromosomes 2 (BTA2) and 5 (BTA5) of purebred, half-sib progeny
sired by five Japanese black bulls were genotyped using microsatellite
DNA markers. The data were subjected to linkage analysis for the
detection and mapping of segregating quantitative trait loci (QTL)
influencing live weight, average daily gain and body measurements at
weaning. Probability coefficients of inheriting allele 1 or 2 from the
sire at specific chromosomal intervals were computed. The phenotypic
data on progeny were regressed on these probability coefficients in a
within-common-parent regression analysis. Fixed effects of sex, parity
and season of birth as well as age as a covariate, were fitted in a
linear model to the phenotypic data and subsequently analysed using QTL
Express by generating an F-statistic through permutation tests at
chromosome-wide significance thresholds over 10, 000 iterations at 1 cM
intervals. Highly significant (P<0.01) segregating QTL for body
measurements were detected on BTA2 for hip width (1 cM) and chest depth
(8 cM) in Sire Family 1 and pin bone width (16 cM) in Sire Family 3.
Other significant QTL (P<0.05) detected were withers height (3 cM), hip
height (4 cM), body length (4 cM), shoulder width (6 cM), lumbar width
(3 cM), thurl width (3 cM) and canon circumference (2 cM) in Sire Family
1, shoulder width (16 cM) in Sire Family 3 and thurl width (24 cM), pin
bone width (19 cM), heart girth (26 cM) and abdominal width (69 cM) in
Sire Family 4. Significant (P<0.05) QTL for live weight and average
daily gain were detected on BTA2 for birth weight (5 cM) and weaning
weight (3 cM) in Sire Family 1 and post-weaning average daily gain (68
cM) in Sire Family 4. BTA 5 contained QTL for birth weight, pin bone
width and heart girth in Sire Family 3 that were only suggestive and not
significant. Such localization of economically important QTL as
demonstrated in this study, will expedite genetic improvement via
marker-assisted selection, gene introgression and positional cloning in
Japanese black cattle.
Key words: QTL mapping, Japanese Black cattle, BTA2, BTA5, body
measurements, live weight, daily gain. |
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