Browsing by Subject "sukusiitosaste"

The traditional method of estimating inbreeding is based on pedigree information, which only considers the known common ancestors of the animals. In recent years, the animal breeding sector has introduced new genomic tools in breeding schemes. The aim of this study was to estimate and compare the level of inbreeding in Finnish Yorkshire and Finnish Landrace pigs using pedigree and genomic methods. Data consisted of pedigree and genotype information from both breeds. In pedigree data there were 503 315 Landrace and 549 296 Yorkshire animals after pruning for pedigree completeness and errors in the data. In the genotype data, there were 522 individuals of Landrace and 934 individuals of Yorkshire animals after pruning. Inbreeding coefficients (FPED) were estimated from pedigree data using RelaX2 program and for genomic data using PLINK by detecting runs of homozygosity (FROH). Percentage of homozygosity (FPH) was also studied from genomic data. Yearly rate of inbreeding based on pedigree raised steadily. Average inbreeding coefficients from year 2014 were 0.10 for Landrace and 0.15 for Yorkshire. The average inbreeding coefficient based on ROHs for animals born in year 2014 were 0.21 for Landrace and 0.25 for Yorkshire animals. Correlation between pedigree-based estimate and genomic-based FROH was found to be quite low for both breeds; 0.51 for Landrace and 0.58 for Yorkshire. The correlation between the two genomic based methods FROH and FPH was high, 0.86 for Landrace and 0.89 for Yorkshire. The level of inbreeding was found to be quite high in both breeds. The genomic-based estimates were higher overall than pedigree-based estimates, which indicates that pedigree data are missing some common ancestors. Based on the results, the level of inbreeding in Finnish pig breeds should be monitored to maintain sufficient genetic diversity in the populations.

Länsisuomenkarja on pienilukuinen populaatio, joka on altistunut sukulaistumiselle ja suku-siitosasteen nousulle. Tutkimuksen tavoitteena oli selvittää länsisuomenkarjan populaation nykytilanne laskemalla tehollinen populaatiokoko, sukusiitosasteen kehitys vuosina 1950‒2014 sekä sukusiitosasteen muutos sukupolvea kohden eri ajanjaksoina. Lisäksi tavoitteena oli tarkastella vanhojen 1960‒80-luvulla syntyneiden sonnien käytön vaikutusta populaati-on perinnölliseen tasoon sekä sukulaistumisen ja sukusiitoksen rajoittamiseen. Populaatioparametrien laskennassa käytettiin sovelluksia RelaX2 ja EVA. Länsisuo-menkarjan teholliseksi populaatiokooksi saatiin 103, mikä on suositusten (50‒100) rajoissa. Niin ikään sukusiitosasteen muutos sukupolvea kohden vuosina 1950‒2014 oli 0,58 %, mikä on suositusten rajoissa (0,5‒1 %). Kuitenkin sukusiitosasteen muutos sukupolvea kohden viime vuosikymmeninä on ollut hieman yli suositusten (1,2 %). Länsisuomenkarjan populaation keskimääräinen sukusiitosaste on noussut tasaisesti vuodesta 1970 alkaen. Sonneista, joilla vielä on annoksia varastossa, alhaisimmat sukulaisuudet nuoriin naarai-siin olivat seuraavilla sonneilla: Ryhti 0,22 %, Viinamäen Akvaviitti 0,33 % ja Lehmon-niemen Aromi 0,49 %. Suurimmat geneettiset kontribuutiot nykyiseen sukupolveen olivat seuraavilla sonneilla: Opari 15,0 %, Tahto 12,6 % ja Pennalan Vekkuli 9,8 %. Simuloitu vanhojen sonnien käyttö parituksissa sai aikaan keskimääräisen sukulaisuuden laskun sekä sukusiitosasteen nousun hidastumisen. Vanhojen sonnien käytöllä oli kuitenkin odotettu negatiivien vaikutus perinnölliseen edistymiseen (kokonaisjalostusarvoon). Lyhyellä aikajänteellä tarkasteltuna länsisuomenkarjan populaatio vaikuttaisi olevan suhteellisen hyvässä tilassa. Kuitenkin sukusiitosasteen nousu saattaa uhata populaation monimuotoisuutta pitkällä tähtäimellä. Vanhojen sonnien harkittu käyttö kahden tai kol-men uuden nuorsonnin tuottamiseksi sukupolvea kohti saattaisi olla järkevä ratkaisu.

The Finnhorse is the only native horse breed in Finland. Finnhorse has faced several genetic bottlenecks that have reduced the breed’s genetic diversity. The aim of this study was to analyse breed’s genetic diversity using pedigree data, focusing on the level of genetic variation and relatedness of the current population (individuals born between 2000 and 2021). In addition to the changes in the inbreeding rate, relatedness, effective population size and generation interval, the study investigated the individuals that have had the greatest genetic impact on the current population, as well as the relationship coefficients of currently used breeding stallions to the current population. Data, including 88 782 animals, was received from Suomen Hippos ry. The average inbreeding coefficient of the horses born between 2000 and 2021 was 4,5 %. The average inbreeding coefficients have increased during the last decades, but the annual growth has been moderate. The mean generation interval was 12,5 years. The growth of the inbreeding coefficient over the past 13 years was 0,97 %. The average relationship of the latest age group to each other was 10,5 %. Relationship between stallions and mares has been increasing throughout the 21st century. After 2013, the average coefficient of relationship between sexes has remained above 11 %. In this study, the effective population size was 93,5 for those born between 2000 and 2021. The effective population size has decreased from 108,6 individuals of the age group born in 2000 to 94,6 individuals born in 2021. However, the effective population size has remained above 50 individuals, which is considered the limit for the occurrence of problems caused by inbreeding at the population level. Current Finnhorse population can be traced back to five founder stallions: Murto, Eri-Aaroni, Suikku, Vokker and Vieteri. Out of those, Murto has the most remarkable contribution on the population born between 2000 and 2021: around 14,2 %. The five founder stallions are all connected by their lineage. The most used breeding stallions of the 21st century were all from trotter breeding direction and their relationship to the mares of the current population ranged from 10,1 to 18,4 %. The lowest relatedness of all breeding stallions to the mares of the current population was 4,0 %. Eight stallions had less than 6,0 % relatedness. None of them were from trotter breeding direction. The genetic diversity of the Finnhorse has remained at a reasonable level, but it is worth noting that the close relationship of breeding stallions in the trotting direction will probably increase rate of relationship in the future. A wider use of genetically divers stallions and a more even number of mares per stallion could slow down the rate of relationship of the breed and increase the effective population size.

The aim of this study was to analyze the development and population structure of the Finnhorse's parentage. The coefficient of inbreeding, the time between generations and the effective population size was studied in the whole population. The effective number of founders and ancestors in the population was determined. The number of horses in the whole population was 77 925 animals. The time between generations was 12.6 years on average. On average, the time between generations was two years longer for stallions than for mares. The effective population size of the Finnhorse was 181, which is sufficient to preserve the genetic diversity of the gene pool. It also examined the degree of kinship and inbreeding with the development of advanced, runner, riding, working - and small horse the direction of the corresponding parameters between the years 1960-2012 and compared with the results obtained in this term. There were 9 585 horses registered in different breeding sections: 6 385 horses in the trotter section, 1 734 horses in the working section, 1 027 horses in the riding second and 439 small Finnhorses. The average coefficient of relatedness in the whole population in 1960–2012 was 2,7-10,7%. The average inbreeding coefficient of inbreeding in the whole population was 1-4,4%. Inbreeding has evolved over the last few decades in the same way as in the past. Stock recorded a runner horses degree of relatedness is, however, significantly increased in recent years. The relatedness between the trotter section and the rest of the population was in the same range than in the whole population. The results of this research concerning different variables were similar to those gathered from studies on other horse breeds. The coefficient of inbreeding and relatedness of the Finnhorse is low enough to ensure that the genetic diversity of the breed will not diminish in the future.