Naslov
Genomic evaluation of sheep populations with low connectedness among flocks

Autori
Kasap, Ante

Vrsta, podvrsta i kategorija rada
Ocjenski radovi, doktorska disertacija

Fakultet
Agronomski fakultet

Mjesto
Zagreb

Datum
10.07

Godina
2015

Stranica
95

Mentor
Mioč, Boro ; Gorjanc, Gregor

Ključne riječi
sheep; accuracy; evaluation; genomic; connectedness

Sažetak
The study aimed to examine the contribution of single-step genomic evaluation to the accuracy of EBVs in populations with low connectedness between flocks, and to compare success of several selective genotyping strategies in sheep populations when limited resources for genotyping are available. The first part of the study was conducted on simulated pedigree and genomic data aiming to mimic sheep populations with various levels of connectedness among flocks and with different genotyping strategies. When disconnectedness was present, the accuracy of EBVs was around zero. Establishment of connectedness led to leap in accuracy of EBVs for all animals in the pedigree (0.44 to 0.72 depending on category) and to increase in the accuracy of EBVs based on genomic prediction. The genetic variance and the size of training set affected the accuracy of EBVs, especially when disconnectedness was present. Training set composed of phenotyped progeny provided higher accuracy of EBVs for prediction set, while training set composed of progeny tested males and phenotyped progeny provided higher accuracy for sires. Second part of the study was conducted on a template of the real structural data of Pag sheep population (supplemented with simulated genomic data). Connectedness analysis performed by the gene-flow method and genetic drift variance revealed poor connectedness among flocks in this population. Genomic approach of genetic evaluation provided higher accuracy of EBVs in comparison to the pedigree based approach, but only when medium- density SNP arrays were used while there was no gain in accuracy with low density SNP arrays. Selective genotyping strategies affected the accuracy of EBVs of particular categories in different manner manifesting the interrelation between the makeup of the training set and accuracy of evaluation.

Izvorni jezik
Engleski

Znanstvena područja
Poljoprivreda (agronomija)

POVEZANOST RADA