Browsing by Author "Partanen, Reeta-Maria"

Effective population size is one of the most important concepts in population genetics. Large enough effective population size is important in maintaining genetic variation in populations. The aim of the study was to estimate effective population size in Landrace and Yorkshire populations and to find out if there is variation in the effective population size between chromosomes and chromosome segments. Effective population sizes were estimated using changes in allele frequencies across generations. Estimation was done from a SNP-genotype data consisting of 1020 Landrace and 1824 Yorkshire boars born in 1996-2013. Average effective population size in Landrace was approximately 40 individuals when estimated at chromosome level and approximately 47 individuals when estimated from chromosome segments. In Yorkshire, the respective estimates were around 37 and 46 individuals. It was noticed that there is variation in the estimated effective population size in both Landrace and Yorkshire populations. In Landrace, the largest chromosome-wise estimates of the effective population size were four times larger than the smallest estimates. The largest chromosome segment based estimates were 21 times larger than the smallest estimates. In Yorkshire, the largest estimates of chromosome-wise effective population size were three times larger and the largest estimates of chromosome segment based effective population size as much as 35 times larger than the smallest ones. The estimates of average effective population size in this study were clearly smaller in both breeds than the estimates of effective population sizes in previous studies that were based on pedigrees or linkage disequilibrium between SNPs. Chromosome-wise or chromosome segment based estimates of effective population size can be utilized in maintaining genetic variation in populations and in optimizing breeding programs.