| Popis: |
Inbreeding depression in dairy production is an extensively studied phenomenon. However, we are not aware of a single study that has estimated inbreeding depression concerning sex chromosome. Using Bayesian inference, we analyzed inbreeding depression in milk yield (4749 Czech Holstein cows genotyped for >40, 000 SNPs with milk yield in the first lactation) in terms of the combined effect of inbreeding (per 1% increase) obtained from autosomes and sex chromosome. We used three models, each based on different estimated inbreeding coefficients (pedigree, ROH>4Mb, or ROH>8Mb). Significant inbreeding depression estimates for autosomes were observed in all three models (medians ; bFPED=-13.2 kg, bFROH > 4Mb=-30.0, and bFROH>8Mb=-34.4 kg), while significant inbreeding depression was observed only for pedigree sex-chromosome estimates (medians ; bFPED-sex=-7.6 kg, bFROH>4Mb-sex=-0.1 kg, and bFROH>8Mb sex=3.9 kg). Low genomic correlations between inbreeding estimated from autosomes and sex chromosome argue for the need to estimate inbreeding depression from sex- chromosome. |
