Conservation and Selection of Genes Related to Environmental Adaptation in Native Small Ruminant Breeds: A Review

Abstract

Environmental stressors have, over generations, influenced the morphology, anatomy, behaviour, physiology, and genetic structure of small ruminants. The widespread dispersal of small ruminants over vast geographical areas occurred along with human migration, thereby promoting the adaptative process to different environmental conditions mainly through natural selection. Ongoing global warming prompted scientific efforts to deepen the knowledge and understanding of adaptation traits in small ruminants. Compared to other ruminants, sheep and goats seem to have a better adaptation ability to environmental stressors, as evident by their presence across different geographic areas on a global level. Adaptation to a specific environment leads to variations in precise genomic regions, allowing for the identification and selection of animals with a high capacity of adaptation to environmental stressors. Rapid development in sequencing technologies, together with bioinformatics tools, make it possible to analyse the genomic regions related to environmental adaptation. Hence, the aims of this review were (i) to outline the main steps of the evolution process in sheep and goat species, (ii) to summarise candidate genes related to environmental adaptation, and (iii) to evaluate both selection and conservation possibilities of these genes in native small ruminant breeds for future challenges to better face the global warming.

Genetic Diversity and Selection Signatures in Economically Important Traits of Ethiopian Indigenous Cattle Breed as a Base for Dairy Cattle Genetic Improvement: A Review

“…Genetic diversity is the total genomic information in a certain species, including all breeds, subpopulations and varieties that fall within that particular species (Demir et al, 2022). Before domestication, the major sources of genetic variation were natural selection, mutation, migration, gene flow and genetic drift; while artificial selection based on the breeders preference (Bahbahani et al, 2018a;Yirsaw, 2021;Demir et al, 2022) is the currently sources of genetic variation.…”

“…However, currently genomic selection provides an answer to both parties and avoids the problems of the past. Selection signatures for production (Singh et al, 2014;Bahbahani et al, 2018a;2018b;Nanaei et al, 2020;Yirsaw, 2021;Saravanan et al, 2021), fitness (Kim et al, 2017;Saravanan et al, 2021;Yirsaw, 2021), environmental adaptation (Kim et al, 2017;Taye et al, 2018;Saravanan et al, 2021;Yirsaw, 2021;Demir et al, 2022) and adaptation to higher and lower altitudes (Terefe et al, 2022) was reported in Ethiopian and other Bos indicus cattle breeds.…”

“…Climate is the single most important ecological factor that determines the growth, development and productivity of domestic animals (Demir et al, 2022). The continuing steady ambient temperature increment is becoming a big challenge that lowers the productivity, even death of animals and causes a significant reduction in biodiversity (Alemayehu and Molla, 2018;Taye et al, 2018).…”

“…The presence of genes responsible for climatic resistance with a varying diversity in the Ethiopian cattle benefits the country in potential use of them for future generation under the continuously changed climatic condition. Demir et al (2022) indicated that the conservation of genomic variants in adaptation will allow animals to adapt to future challenges, benefit farms for sustainable use of local breeds and these animals will be the only answers in the ongoing global warming.…”

Pırlak Koyun Irkında Bir Batında Doğan Yavru Sayısı ile Ilişkili PRL ve BHR Genlerindeki inDel Varyasyonlar

“…Variations in the genomic regions related to litter size allow farmers to improve selection strategies in which animals with desired genotype are used for mating programs (Demir et al, 2022). Also known as Marker Assisted Selection (MAS), this kind of selection is of possibility to increase the frequency of the desired genotype by which litter size are increased from one generation to another.…”