A comprehensive analysis of the genetic diversity and environmental adaptability in worldwide Merino and Merino-derived sheep breeds

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 demographic history and adaptation of Canarian goat breeds to environmental conditions through the use of genome-wide SNP data

“…In this context, it is well-known that body size is strongly related to warm climate responses and might impose severe constraints on adaptive variation [ 52 , 53 ]. Moreover, this genomic region also overlapped with previously reported ROH islands in southern Italian goats [ 18 , 54 , 55 ] and in Merino and Merino-derived sheep breeds reared in different climatic zones [ 56 ]. One last genomic region shared between the two approaches was detected on CHI6 (16.4–18.2 Mb) in both the PAL-TIS window-based F ST comparisons and in the Palmera ROH islands.…”

Whole genome sequencing identified genomic diversity and candidated genes associated with economic traits in Northeasern Merino in China

“…FTO , which has been reported to be associated with a variety of fat-related traits in animals ( Chang et al, 2018 ), especially, is linked with tail fat deposition in Hu sheep ( Zhao et al, 2022a ). CTNNBL1 ( Yin et al, 2012 ), and SLIT2 ( Mastrangelo et al, 2019 ; Ceccobelli et al, 2023 ) are also involved in fat deposition. YARS2 was related to mitochondrial protein synthesis and mitochondrial respiration, the results of a genome-wide association analysis of Yorkshire pigs suggest that it might be associated with the feed conversion rate ( Miao et al, 2021 ).…”

Situación genética de las principales líneas puras del merino español

“…Genetic distances of Nei (1972) between the animals of the different strains present in the study. Tascón et al, 2000;Ceccobelli et al, 2023).…”

“…Por otro lado, las diferencias observadas entre las líneas de Merino se han mantenido en niveles similares a los que se pueden observar en las líneas genéticas reconocidas en otras razas como el Merino Australiano (líneas Merino industrial y Merino de lana) (Ceccobelli et al, 2023).…”