Support for single major genes influencing fat androstenone level and development of bulbo-urethral glands in young boars

MN Fouilloux, P. Le Roy, J. Gruand, C. Renard, P. Sellier, M. Bonneau
1997 Genetics Selection Evolution  
A two-step genetic analysis was performed on data collected in a fourgeneration selection experiment comprising a control and a selected line in a Large White-Landrace crossbred population. The two-trait selection index used for choosing replacement boars of the selected line included fat androstenone level and the average thickness of right and left bulbo-urethral glands, the latter trait being an indicator of the sexual maturity status of young boars. Fat androstenone level was determined on
more » ... was determined on a biopsy sample of backfat taken at 118 kg liveweight, whereas bulbo-urethral gland size was measured by echotomography, using a rectal probe, at 99 kg liveweight. A total of 949 entire males, from 57 sires and 353 dams, were recorded for both traits. In the first step of analysis, REML genetic parameters were estimated using a bivariate animal model. Heritability estimates (f SE) were 0.55 f 0.07 for fat androstenone level and 0.63 ! 0.05 for bulbo-urethral gland size. A fairly close genetic correlation (0.68 f 0.05) was found between the two traits. The second step of analysis consisted in testing the hypothesis of a mixed mode of inheritance (polygenes + major gene) for each trait using segregation analysis methods. A major two-allele gene was found to affect fat androstenone level. Under the genetic model that best explained the situation, the 'low androstenone' allele
doi:10.1051/gse:19970304 fatcat:sluc5fd2onarrdfdzmzcoympf4