Loci associated with negative heterosis for viability and meat productivity in interspecies sheep hybrids

by Alexander S. Zlobin | Natalia A. Volkova | Natalia A. Zinovieva | Baylar S. Iolchiev | Vugar A. Bagirov |
Pavel M. Borodin | Tatiana I. Aksenovich | Yakov A. Tsepilov | Kurchatov Genomic Center of the Institute
of Cytology and Genetics, SB RAS, Novosibirsk, Russia | L.K. Ernst Federal Science Center for Animal
Husbandry, Dubrovitsy, Moscow Region, Russia | Institute of Cytology and Genetics, SB RAS,
Novosibirsk, Russia 

The modern market demands the animal breeds or breed types characterized by good
viability, high growth rate and ability to effectively use feed. One of the way to improve the
existing breeds is obtaining of breed hybrids. Hybrids are expected to have the increasing of
the economically important traits because of mixing the genetic contributions of its parents.
However, earlier for hybrids of romanovskaya sheep and argali (Ovis ammon) negative
heterosis was shown for meat productivity traits and viability. In this work, we aimed to find
genetic loci associated with negative heterosis in these hybrids.
In total we have studied 87 backcross of romanovskaya x argali. Viability information was
available for four time-points after animal birth (6 days, 42 days, 3 months, 6 month). We
used four indexes related to meat productivity (compactness, shortlegged, length and
cumulative) measured at 42 days after animal birth. We used Cox regression for viability
GWAS analysis and linear model for GWAS analysis of meat productivity traits. For each of
the trait we used additive and three non-additive models (dominant, recessive,
overdominant). As covariates, we used sex, number of fetuses, last time interval with
available phenotype information, two first genetical principal components of kinship matrix
and PRS (Polygenic risk score) for SNPs shown as associated with mortality.
The results can be useful for further association studies and preliminary estimation of
genetic variability for economically important traits in different sheep breeds.