Research article - Peer-reviewed, 2005
Many QTLs with minor additive effects are associated with a large difference in growth between two selection lines in chickens
Jacobsson L, Park HB, Wahlberg P, Fredriksson R, Perez-Enciso M, Siegel PB, Andersson LAbstract
Two growth-selected lines in chickens have been developed from a single founder population by divergent selection for body weight at 56 days of age. After more than 40 generations of selection they show a nine-fold difference in body weight at selection age and large differences in growth rate, appetite, fat deposition and metabolic characteristics. We have generated a large intercross between these lines comprising more than 800 F-2 birds. QTL mapping revealed 13 loci affecting growth. The most striking observation was that the allele in the high weight line in all cases was associated with enhanced growth, but each locus explained only a small proportion of the phenotypic variance using a standard QTL model (1.3-3.1%). This result is in sharp contrast to our previous study where we reported that the two-fold difference in adult body size between the red junglefowl and White Leghorn domestic chickens is explained by a small number of QTLs with large additive effects. Furthermore, no QTLs for anorexia or antibody response were detected despite large differences for these traits between the founder lines. The result is an excellent example where a large phenotypic difference between populations occurs in the apparent absence of any single locus with large phenotypic effects. The study underscores the need for powerful experimental designs in genetic studies of multifactorial traits. No QTL at all would have reached genome-wide significance using a less powerful design (e.g. approx. 200 F-2 individuals) regardless of the nine-fold phenotypic difference between the founder lines for the selected traitPublished in
Genetics Research2005, volume: 86, number: 2, pages: 115-125
Publisher: CAMBRIDGE UNIV PRESS
Authors' information
Swedish University of Agricultural Sciences, Department of Animal Breeding and Genetics
Andersson, Leif
Swedish University of Agricultural Sciences, Department of Animal Breeding and Genetics
Park, H B
Perez-Enciso, M
Walhberg, P
Siegel, P B
Fredriksson, R
UKÄ Subject classification
Animal and Dairy Science
Veterinary Science
Publication Identifiers
DOI: https://doi.org/10.1017/S0016672305007767
URI (permanent link to this page)
https://res.slu.se/id/publ/8060