Identification of QTL for live weight and growth rate using DNA markers on chromosome 3 in an F2 population of Japanese quail.

The Japanese quail (Coturnix japonica) is an important agricultural species and is an animal model for genetic researches. This study was conducted to identify quantitative trait loci (QTL) affecting live weight and growth rate on chromosome 3 in quail. Two strains of Japanese quail including wild and white were crossed reciprocally and F1 generation was created. The birds from F2 generation were measured for growth traits and all of 472 birds (8 pairs from the parental strains, 34 F1 birds and 422 F2 birds) were genotyped for microsatellite markers on chromosome 3. The results indicated chromosome wide significant QTL for hatching weight (P < 0.01) and weight at 1, 2, 3 and 4 weeks of age, average daily gain from hatch to 1, 1-2 and 3-4 weeks of age and Kleiber ratio (P < 0.05), an indirect criterion of feed efficiency. The highest QTL additive and imprinting effects (2.72 and 0.79 % of the trait variation in the F2 population, respectively) were related to hatching weight. The identified QTL for this trait (at 7 cM relative to the centromeric region of the chromosome) had significant interaction with sex and hatch (P < 0.01). The dominance effect of QTL was significant (P < 0.05) for bodyweight at one week of age accounting for 1.69 % of the trait variation in the F2 population.