Browsing by Author "Luukkonen, Terhi"

The adequate genetic diversity of the population is important for selection and population adaptation. In production animals, population diversity, coancestry and the rate of inbreeding have often been studied based on pedigree information. Their reliability depends on the quality of the pedigree. Analysis of population diversity at the genomic level gives more reliable estimates of the true diversity of populations than pedigree. The aim of this study was to estimate inbreeding in North European short-tail sheep populations and the differentiation and admixture of the breeds based on the genomic data. The data contained 435 sheep; 112 Finnsheep, 22 Åland, 94 Texel, 96 Iceland, and 102 Romanov sheep. All samples but Romanov and Iceland sheep samples were collected in Finland. The samples were genotyped with Illumina ovine 700K BeadChip. Using the PLINK program, population segregation, mean homozygosity and runs of homozygosity (ROH) were evaluated. Inbreeding was estimated either based on ROH sequences (FROH), general homozygosity (FPH) or standardized homozygosity (FHOM). Population mixing was studied with the Admixture program. The average inbreeding levels (FROH) were 0,17 for Åland sheep, 0,09 for Finnsheep, 0,13 for Texel, 0,15 for Iceland sheep, and 0,08 for Romanov. Based on the multidimensional scaling, the genetically closest breeds were the Finnsheep and Åland sheep, although in the analysis of admixture, Finnsheep and Åland sheep formed separate populations. The results obtained are in line with previous studies on the genetic diversity of the Finnish sheep populations. Based on the results, the genetic diversity of native sheep breeds is sufficient and on a solid basis. In order to keep the situation good, it is important to continue maintaining sheep registers and breeding programs and continue to invest in the preservation program.