Search

Abstract Background To enhance and extend the knowledge about the global historical and phylogenetic relationships between Merino and Merino-derived breeds, 19 populations were genotyped with the OvineSNP50 BeadChip specifically for this study, while an additional 23 populations from the publicly available genotypes were retrieved. Three complementary statistical tests, Rsb (extended haplotype homozygosity between-populations), XP-EHH (cross-population extended haplotype homozygosity), and runs of homozygosity (ROH) islands were applied to identify genomic variants with potential impact on the adaptability of Merino genetic type in two contrasting climate zones. Results The results indicate that a large part of the Merino’s genetic relatedness and admixture patterns are explained by their genetic background and/or geographic origin, followed by local admixture. Multi-dimensional scaling, Neighbor-Net, Admixture, and TREEMIX analyses consistently provided evidence of the role of Australian, Rambouillet and German strains in the extensive gene introgression into the other Merino and Merino-derived breeds. The close relationship between Iberian Merinos and other South-western European breeds is consistent with the Iberian origin of the Merino genetic type, with traces from previous contributions of other Mediterranean stocks. Using Rsb and XP-EHH approaches, signatures of selection were detected spanning four genomic regions located on Ovis aries chromosomes (OAR) 1, 6 and 16, whereas two genomic regions on OAR6, that partially overlapped with the previous ones, were highlighted by ROH islands. Overall, the three approaches identified 106 candidate genes putatively under selection. Among them, genes related to immune response were identified via the gene interaction network. In addition, several candidate genes were found, such as LEKR1, LCORL, GHR, RBPJ, BMPR1B, PPARGC1A, and PRKAA1, related to morphological, growth and reproductive traits, adaptive thermogenesis, and hypoxia responses. Conclusions To the best of our knowledge, this is the first comprehensive dataset that includes most of the Merino and Merino-derived sheep breeds raised in different regions of the world. The results provide an in-depth picture of the genetic makeup of the current Merino and Merino-derived breeds, highlighting the possible selection pressures associated with the combined effect of anthropic and environmental factors. The study underlines the importance of Merino genetic types as invaluable resources of possible adaptive diversity in the context of the occurring climate changes.

The aim of the study was to investigate the distribution of prion protein PRNP alleles in flocks of Polish Merino and Suffolk sheep. The research was conducted in 2012-2017 on ewes and rams kept in the Golina Wielka sheepfold (Greater Poland Voivodeship, Poland). All animals (264 ♀ and 64 ♂ Polish Merino; 98 ♀ and 73 ♂ Suffolk) were up to one year old. PRNP gene polymorphism was identified in the sheep. The frequency of scrapie alleles and genotypes was found to be highly significantly influenced by the breed and significantly influenced by the year in the case of Polish Merino sheep. Five alleles (ALRR, ALRQ, ALHQ, AFRQ and VLRQ) were detected in Polish Merino sheep, leading to the identification of 10 PRNP genotypes. In the Suffolk breed, three alleles (ALRR, ALRQ and ALHQ) and three genotypes were identified. In the Polish Merino breed, the frequency of the ALRR/ALRQ genotype was high and was the highest among all genotypes, followed by ALRR/ALRR. The level of genotypes containing valine at codon 136 was very low. In the Suffolk breed, the frequency of the ALRR/ALRR genotype was very high, and there were no alleles with valine at codon 136. In addition, in Polish Merino sheep, phenylalanine at codon 141 was detected only in the AFRQ allele, which appeared in two genotypes (in combination with ALRR and ALRQ).

The aim of the study was to compare two mating systems and their impact on reproductive parameters in sheep of the synthetic WROBER line and to evaluate the profitability of lamb meat production. Sheep were raised at the Agricultural Experimental Station in Żelazna (Warsaw University of Life Sciences) in a traditional system with mating once a year and at the Werbkowice Experimental Farm (Institute of Soil Science and Plant Cultivation – National Research Institute) in an intensified system with a shortened lambing interval. The study confirmed the suitability of the WROBER line for intensive production of slaughter lambs. In this system, 0.5 more lambs were obtained per ewe (in all seasons) than in the traditional system. Due to the increased number of lambs produced, the WROBER line can become more profitable.