Geneetilise muutlikkuse hindamine inbriidingukoefitsiendi alusel: põlvnemisandmed versus genoomiinfo
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Kuupäev
2025
Kättesaadav alates
04.09.2025
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Piimaveiste aretuses on aina aktuaalsemaks teemaks paratamatu sugulusaretus ehk inbriiding. Selle mõjusid on hakatud rohkem uurima ja otsima, kuidas vältida loomade geneetilise mitmekesisuse vähenemist. Inbriidingu hindamiseks on erinevaid meetodeid, mida uuritakse ka antud töös. Käesoleva bakalaureusetöö eesmärgiks oli uurida genoomiinfo ja sugupuuandmetel leitud inbriidingukoefitsientide vahelisi seoseid ja mõju jõudlus- ja funktsionaalsetele tunnustele.
Töös analüüsiti 42 juba karjast lahkunud Eerika Farm OÜ eesti holsteini tõugu lehma andmeid. Tulemused näitasid, et keskmine inbriidsus genoomiandmetel (Froh) oli kõrgem kui põlvnemisandmete alusel (Fpk), kuid Froh ja Fpk vahelised seosed olid väga nõrgad. Antud töös saadi viie põlvkonna andmete põhjal keskmiseks inbriidingukoefitsiendiks Fpk5=0,0167 ning genoomiandmetega Froh>1Mb=0,0918. Genoomiinfo võimaldas kirjeldada üleüldist olukorda ning seoseid tunnustega sugulusaretuse taustal mitmekesisemalt.
Uurimuse käigus selgus ka, et erineva pikkusega homosügootsete segmentide alusel leitud inbriidingu ja rea aretustunnuste vahel on erineva suunaga seosed, näiteks lühemad ROHid (Runs of Homozygosity) korreleerusid pigem positiivselt loomade funktsionaalsete tunnustega ning negatiivselt toodangu tunnustega ja vastupidi pikkade ROHide puhul.
In dairy cattle breeding, the increasingly relevant topic is inevitable inbreeding. Its effects have started to receive more attention, and efforts are being made to find ways to prevent the loss of genetic diversity in animals. There are various methods for evaluating inbreeding, which are also explored in this study. The aim of this bachelor's thesis was to investigate the relationships between inbreeding coefficients derived from genomic information and pedigree data, as well as their effects on performance and functional traits. The data of 42 Estonian Holstein cows from Eerika Farm OÜ, which had already been culled from the herd, were analyzed. The results showed that the average inbreeding coefficient based on genomic data (Froh) was higher than that based on pedigree data (Fpk), but the correlations between Froh and Fpk were very weak. Based on five generations of pedigree data, the average inbreeding coefficient was found to be Fpk5= 0,0167, while from genomic data it was Froh>1Mb= 0,0918. Genomic information provided a more comprehensive overview of the overall situation and associations with traits in the context of inbreeding. The study also revealed that inbreeding based on homozygous segments of different lengths (Runs of Homozygosity, ROH) showed associations in different directions with breeding traits. For example, shorter ROHs tended to correlate positively with animals’ functional traits and negatively with production traits, whereas the opposite was true for longer ROHs.
In dairy cattle breeding, the increasingly relevant topic is inevitable inbreeding. Its effects have started to receive more attention, and efforts are being made to find ways to prevent the loss of genetic diversity in animals. There are various methods for evaluating inbreeding, which are also explored in this study. The aim of this bachelor's thesis was to investigate the relationships between inbreeding coefficients derived from genomic information and pedigree data, as well as their effects on performance and functional traits. The data of 42 Estonian Holstein cows from Eerika Farm OÜ, which had already been culled from the herd, were analyzed. The results showed that the average inbreeding coefficient based on genomic data (Froh) was higher than that based on pedigree data (Fpk), but the correlations between Froh and Fpk were very weak. Based on five generations of pedigree data, the average inbreeding coefficient was found to be Fpk5= 0,0167, while from genomic data it was Froh>1Mb= 0,0918. Genomic information provided a more comprehensive overview of the overall situation and associations with traits in the context of inbreeding. The study also revealed that inbreeding based on homozygous segments of different lengths (Runs of Homozygosity, ROH) showed associations in different directions with breeding traits. For example, shorter ROHs tended to correlate positively with animals’ functional traits and negatively with production traits, whereas the opposite was true for longer ROHs.
Kirjeldus
Bakalaureusetöö
Loomakasvatuse õppekaval
Märksõnad
bakalaureusetööd, piimalehmad, aretus, homosügootsed segmendid, SNPd