Detection of major gene for productive traits in Fars native fowls using Bayesian segregation approach

In the current study, major gene segregation for body weight at 8 weeks of age (BW8), age at sexual maturity (ASM), average egg weight during 84 days of laying (EW) and number of eggs laid during egg production period (EN) traits were evaluated using data which was collected from Fars Native Breeding Center. Cox Box transformation was applied for all traits except for EN. Major gene detection was achieved by using highest posterior density region for genetic variance of major gene in the population. Therefore, a Bayesian segregation analysis model including non-genetic effects (generation-hatch, sex as fixed and laying period as covariate) and genetic effects (polygenic and biallelic major gene locus as random and fixed ones, respectively) was fitted on the data. The marginal posterior distribution of the model parameters were obtained by Gibbs sampling using iBay software. Based on diagnostic tests for each trait, two large chains were considered. For each chain, the number of Gibbs samples, burn in, and thining interval were equal to 500000, 50000 and 50, respectively. The Bayesian segregation analysis revealed the evidence for major gene segregation for ASM. For other traits there were not the same results. It is also recommended that the laboratory methods should be applied to verify the present results as well as additional methods for major gene detection for variety of traits in the same population.