engleski

The impact of maternal inheritance on the milk production traits in Holstein cows

The influence of the whole mitochondrial genome sequence on milk production traits (milk, fat and protein yield) was evaluated in Holstein cows. Complete mitogenomes were sequenced representing 109 maternal lineages using NGS technology. MaGelLAn 1.0 software has enabled assignment of mitogenome sequence haplotype information to 2373 cows with their production records. Here, we present quantitative genetic model that provides, in addition to additive and environmental effects, estimates of the mitogenome and sex-chromosome variance components. Age at first calving was used as covariate and was modelled as linear regression. Region (county) was included in model as fixed class effect. The estimated proportions of the phenotypic variances that were explained by mitogenome haplotypes ranged from 6% to 7% for all three milk traits. At the same time, the estimated effects of sex-chromosome loci were negligible. We have shown that for the milk production traits considerable proportion of the phenotypic variance was explained by mitogenome haplotype variation. While more general confirmation is still needed, the results obtained argue for including mitogenome effects in the estimation of quantitative genetic parameters further fostering improvement of existing breeding programs.

milk production traits, mitochondrial genome, Holstein cattle, variance components, next generation sequencing (NGS)

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