Browsing by Subject "heritability"

There has been a steady increase in alcohol consumption in Finland since the 1969 law reform, which allowed convenience stores to sell mild alcoholic beverages such as beer. Since then, the yearly consumption has increased from 3.6 liters in 1968 to 10.8 liters of pure alcohol per capita in 2016. Increasing levels of alcohol use tend to produce high economic and population health costs. Understanding why changes in alcohol consumption behavior occur enables development of more efficient prevention and intervention programs. Alcohol consumption is not distributed equally across the population. Liberalization of Finnish alcohol policy and culture from the 1960s onwards made alcohol more available than ever before, and especially the post-war cohorts started to use significantly more alcohol than the generations before them. Evidently, there are between-individual differences in alcohol use in addition to group level differences. According to decades of research, approximately 50% of the variation between individuals in alcohol consumption can be explained by genetic sources. In other words, the heritability of alcohol use is 50%, while non-genetic factors explain the other half. However, heritability is not a static estimate, but can be modified by social forces. While it has been established that the younger generations consume significantly more alcohol than generations preceding them, only a few studies to date have examined whether the importance of genetic influences on alcohol consumption is dependent on birth cohort or generation. The current study examined, if social control during a specific time in history (e.g. how strict is alcohol policy and the cultural climate while a generation is growing up) can affect the heritability of alcohol use in later life. Mean level differences in alcohol consumption quantity and abstinence trajectories of birth cohorts were also estimated. The older Finnish twin cohort data consists of all Finnish same-sex twin pairs born before 1958 with both co-twins alive in 1975 (n = 24 481). The data were collected in four waves in 1975, 1981, 1990, and 2011. Age of the participants at study baseline in 1975 ranged from 18 to 95. Participants were grouped into seven 10-year cohorts based on their birth year. Mean trajectories of alcohol consumption quantity and abstinence over the life course were estimated for men and women separately with hierarchical growth curve models. Cohort effects and age-by-cohort interactions were also investigated. The heritability of alcohol consumption and abstinence was estimated using structural equation modelling. Birth cohort effects on heritability of alcohol use were examined by comparing heritability estimates of different cohorts at similar ages. Mean levels of alcohol consumption quantity were the highest in the youngest birth cohorts. Women drank less than men in all cohorts. The decline in the quantity of monthly alcohol use due to aging was relatively small, and appeared to be more prominent in the older birth cohorts. The odds of abstaining became lower in every successive birth cohort. Moreover, women were more likely to be abstinent than men. The aging effect of increasing abstinence was notable only in the oldest birth cohorts. Birth cohort differences in the heritability of alcohol consumption quantity were found: heritability was 25% (CI 12–38%) in the older generation (born 1901–1920) and 48% (CI 39–50%) in the younger generation (born 1941–1957) of men at the age of 54–74. For women, heritability was 60% in the older and younger generation. In alcohol abstinence, a single model was run for men and women. The shared environmental component explained a large proportion of the variation in the older generation (43%), whereas unique environment (54%) and additive genetic influences (40%) were more important among the younger generation. The findings from the present study suggest that social control during a specific time in history may have a long-term impact on alcohol consumption behavior (i.e. how and why alcohol is used) of an entire generation growing up during that period.

The aim of this study was to estimate the genetic parameters of elk hunting traits in Jämthunds. There were nineteen traits under consideration. Heritabilities, repeatabilities, and genetic and phenotypic correlations were estimated for the traits. Also, coefficient of inbreeding and genetic trends were estimated. The data consisted of results from official elk hunting trials collected by Suomen Harmaahirvikoirajärjestö ry in 2012-2016. There were 46 221 results, from which 23 335 of Jämthunds. The pedigree data was provided by The Finnish Kennel Club and it included 31 544 Jämthunds. Significance of the fixed effects was estimated using F-test in analysis of variance with RStudio 1.0.136. The pedigree was pruned with RelaX2 1.54-pedigree analysis programme. Variance components were estimated with DMU-package using AI-REML-approach. The estimated heritabilities were low and varied between 0.00 and 0.047. The highest heritability was obtained for search and the lowest for obedience during work. Genetic correlations varied from -0.25 to 0.98, and the strongest were estimated for most of the bark related traits. The genetic trend has been positive in all traits, except for obedience traits. The coefficient of inbreeding for dogs born in 2016 was approximately 7.03 %, and the coefficient of inbreeding has decreased 0.26 % in the last decade. There are multiple non-genetic factors that affect the traits, and the data is based on subjectively evaluated variables. It is possible to improve genetic evaluation by collecting more information on trial conditions, by using the whole scale of points during the evaluation, and by making more objective evaluations of the traits. The estimated breeding values of the important traits can be used in selection of the parent of the next generation.

Patellaluksaatio (PL) eli polvilumpion sijoiltaanmeno on etenkin pienten koirien yleinen ortopedinen sairaus. Polvilumpio voi luksoitua mediaalisesti tai lateraalisesti. Mediaalinen luksaatio on huomattavasti yleisempi kuin lateraalinen. PL:lla arvellaan olevan perinnöllinen tausta, sillä tietyillä roduilla esiintyvyys on korkea ja oireet alkavat nuorena. PL arvioidaan koirasta nk. Putnamin arvosteluasteikolla palpoimalla ja manipuloimalla polviniveltä. PL arvostellaan välillä 0=terve…4=pysyvä luksaatio. Tämän tutkimuksen tavoitteena oli määrittää PL-aineiston ja sukupuuaineiston avulla PL-fenotyypin varianssikomponentit, periytymisaste, geneettinen trendi, oikean ja vasemman polven geneettinen korrelaatio sekä japaninpystykorvalle edellisten lisäksi PL:n ja lonkkadysplasian (HD) geneettinen korrelaatio. Tutkimusrodut olivat chihuahua, pomeranian, suomenpystykorva sekä japaninpystykorva. PL-, HD- ja sukupuuaineistot saatiin Suomen Kennelliitto ry:ltä. Aineistot muokattiin sopivaan muotoon R- ja Microsoft Office Excel-ohjelmistoilla. Sukupuiden laaduntarkastus tehtiin RelaX2-ohjelmistolla. Varianssikomponentit laskettiin DMU-ohjelmistolla REML-menetelmää käyttäen (Restricted Maximum Likelihood). Periytymisasteet (h2) olivat hyvin matalia tai matalia riippuen mallista ja rodusta. Kun tarkasteltava fenotyyppi oli koiran vasemman ja oikean polven keskiarvo, matalin h2 oli pomeranianilla h2=0,03 ja korkein chihuahualla h2=0,18. Vasemman ja oikean polven geneettinen korrelaatio oli kaikissa roduissa 1, mikä viittaisi siihen, että geneettisesti kyseessä on sama ominaisuus. Japaninpystykorvan PL:n ja HD:n geneettinen korrelaatio oli -0,05. Jalostusarvojen trendi oli myönteinen chihuahualla ja japaninpystykorvalla. Trendi oli negatiivinen pomeranianilla ja neutraali suomenpystykorvalla. Tämän tutkimuksen tulosten perusteella yksilön omaan tulokseen perustuva jalostusvalinta ei ole ollut tehokasta PL:ta vastustettaessa. Polviterveyttä tulisi edistää koirissa käyttämällä valintatyökaluna jalostusindeksejä, sillä PL:n periytymisaste on matala. Jalostusvalinta voisi tehostua ominaisuuden fenotyypityksen kehittämisen myötä.

The Finnish dairy cattle population has been subjected to systematic quantitative studies over decades. The Western Finncattle (WFC) has evolved over the last century with a production level comparable to other remaining local breeds in Europe. The heritability is used in designing the data collection and in predicting the changes expected from the selection and the variation parameters are used in constructing the economic selection indices genetic improvement scheme and in computing the bulls’ and cows’ breeding values. WFC has no recent studies on the genetic variation in milk production traits. The thesis research was set to estimate the heritability of milk, fat and protein yield, fat%, protein%, protein-fat ratio and somatic cell count (SCC) and the genetic correlation amongst them. Records from Western Finncattle primiparous cows calving in the period 2002–2016 were used for the genetic analyses. The raw data consisted of 5455 cows distributed across 2512 herds. The variance components were estimated with single and multi-trait animal model using a Bayesian approach and R studio package MCMCglmm. With requiring at least 5 cows in each herd-year subclass in the estimation, the data size was reduced to 1763 cows in 233 herds. The heritability of milk, protein and fat yield, protein%, fat% and SCC was in single (and in brackets for multi) trait analysis 0.36 (0.37), 027(0.30), 0.32 (0.30), 0.61(0.43), 0.52 (0.49) and 0.06 (0.15), respectively. Amongst yield traits and also between the content traits the genetic correlation was high, 0.73–0.94 and 0.43–0.59, respectively. The content traits (with milk yield in the denominator) had a negative genetic correlation with milk yield while no correlation with the protein and fat yield. There was an environmental correlation between content and yield traits for protein and fat. No correlations exist between SCC and other traits except an environmental correlation with milk yield and protein content. Despite the small population size of the WFC population, the effective population size is satisfactory and therefore no reduction in genetic variation is expected. Overall, the analysis on production traits and pedigree data shows that the Western Finncattle have much potential for genetic improvement.

The target of pork production is to produce lean meat efficiently in a sustainable way taking into account environment and ethical aspects. The most important production traits in pigs are average daily gain, feed efficiency and leanness. A lot of research is conducted related to production traits in comparison to feeding behavior traits. The objective of this study was to estimate heritability of feeding behavior traits and their genetic correlations with production traits in Finnish Landrace population. The data included feeding records of 4059 Landrace pigs measured automatically in Figen’s test station. The pigs had started their test period during 2010 - 2016. The measured traits were the number of visits per day (NVD), time spent in feeding per day (TPD), daily feed intake (DFI), time spent feeding per visit (TPV), feed intake per visit (FPV), feeding rate (FR), average daily gain (ADG), back fat thickness (BF) and feed conversion ratio (FCR). Feeding behavior traits were divided into 5 periods. Heritability estimates of feeding behavior traits were moderate. The heritability estimates were 0,22-0,29 for NVD, 0,33-0,47 for TPD, 0,16-0,25 for DFI, 0,22-0,31 for TPV, 0,28-0,36 for FPV, 0,35-0,38 for FR, 0,27 for ADG, 0,22 for BF, and 0,24 for FCR. Compared to other published results heritabilities of TPD and FR were similar. However, heritabilities of other feeding behavior traits were quite low compared to published results. In addition, heritability of BF was unexpectedly low. The genetic correlations of feeding behavior traits were similar at different test periods. The highest positive genetic correlations were between traits TPV – FPV, FPV – FR, and NVD – TPD. The highest negative genetic correlations were between traits NVD – FPV, TPD – FR, and NVD – TPV. Genetic correlations between feeding behavior traits and production traits were low. Only between DFI – ADG, DFI – FCR, and FPV – FCR the genetic correlations were significant (and positive). In conclusion, heritabilities of feeding behavior traits were moderate. Because the only strong genetic correlation between feeding behavior and production traits was obtained between DFI and ADG, including feeding behavior traits in breeding programs is not necessary. However, feeding behavior data are easy to collect from the electronic feeders and the observations are reliable, thus daily feeding records can be used for monitoring animal’s health and welfare.

Canine uveal melanoma (UM) usually manifests as a slowly developing, darker pigmented and well distinguishable mass in the iris. Less than a third of them are considered malignant, which is much less than with other melanocytic cancers. In contrast, in humans, 90% of UM occurs in the choroid and half of the patients eventually develop aggressive and often lethal metastases. Understanding the disease process and genetic background in dogs might also help us further the knowledge and improve the treatment options of humans. There is a hereditary component to the oncogenesis of the UM: the disease is more common in a Caucasian race and is also found in certain families. It is also more prevalent in certain dog breeds; Labrador Retrievers seem to be overrepresented. Several susceptibility genes have been identified in humans. One with the strongest association with UM is a tumor suppressor gene BAP1, which is dysfunctional or missing in nearly half of the human uveal melanomas. This gene is a so-called secondary driver of the UM and mutations in it spark the metastasizing process. There is a germline mutation of BAP1 in fourth of Finnish UM families and these mutations are also connected to various other cancers. Moreover, BAP1 shows over 98% protein product homology and almost 80% mRNA homology between dogs and humans, making it an appealing study target also for canines. Should a single variant account for high UM risk, a DNA test could be developed to be used in breeding and veterinary diagnostics. In this work, I mapped the BAP1 germline mutations of seven Labrador Retrievers with diagnosed uveal melanomas or melanocytomas. It was found that four dogs shared the same set of five heterozygous single nucleotide variants (SNV). One of the SNVs within exon 17 was synonymous, g.37,363,076G>A, p.(Ser721Ser), while the other four SNVs were intronic, residing close to exons 4, 10, 11 and 14. In the future, variant comparisons with healthy Labradors are needed to study the role of the identified variants for the development of UM, as the SNVs now found could also just be a part of a common variation in the Labrador Retriever gene pool. To grasp a bigger picture of the UM tumor development, the tumors themselves should also be analyzed for somatic mutations. Moreover, when we know that the disease is likely affected by over a hundred genes, studying just one gene is unnecessarily self-restricting. Modern full genome sequencing techniques should be used for catching all the predisposing genes simultaneously.