Genetic relationships among six Iranian indigenous sheep populations based on microsatellite analysis

Genetic structure of Iranian indigenous sheep breeds: insights for conservation

Genetic structure and genetic diversity levels of indigenous Iranian sheep breeds are not clear, despite the interest this region has in itself as an important center for domestication of livestock. Early population genetic studies have reported high levels of diversity among Iranian sheep breeds until recently, when high admixture levels and genetic homogeneity have been detected. The rapid reduction of diversity observed in Iranian breeds might be due to an increasing trend of intensive crossbreeding practices or even total replacement of native breeds by highly specialized and productive ones. From a conservative perspective, this situation is highly concerning; thus, it might be wise to consider a conservation program in Iran to preserve the original genetic diversity in native sheep breeds. In this study, a total of 1065 animals with the purest morphological features representing 24 Iranian indigenous sheep breeds were sampled, corresponding to ancestral breed diversity. These samples were genotyped for 17 microsatellite loci in order to (1) determine the native ancestral diversity of Iranian breeds, (2) define the degree of genetic relationship among studied breeds, and (3) assess conservation priorities among defined groups. Our results showed no recent loss of diversity, but high genetic diversity levels for indigenous sheep breeds in Iran. Indeed, the analysis of conservation priorities pointed out the importance of 8 breeds for maintaining Iranian sheep breeds' maximum genetic diversity. Thus, under a genetic perspective, these 8 breeds should be the ones included into conservation programs for restocking endangered areas.

PCR-SSCP Variation of IGF1 and PIT1 Genes and Their Association with Estimated Breeding Values of Growth Traits in Makooei Sheep

Molecular biology techniques genetic improvement by facilitating identification, mapping and analysis of polymorphism of genes by encoding proteins that act on metabolic pathways involved in economically interesting traits. This use of genetic markers can aid identification of those animals with the highest breeding values in sheep. On the basis of sheep genome mapping, information was examined on the ovine IGF1 and PIT1 genes as a possible genetic marker for growth traits in sheep. The current study was designed to estimate the frequencies of putative IGF-1 and PIT-1 genes SNPs and investigate associations with calculated EBVs of growth traits in Makooei sheep. PCR-SSCP analysis of the exon1 of IGF-I gene and include a part of intron2, exon3 and a part of intron3 and PIT-1 gene revealed the following banding patterns; three (AA, AG, GG) and four AA (p1), AB (p2), CC (p3), CD (p4), banding patterns respectively. Results from this study demonstrated higher performance of AA animals in BW and GBW, and AG animal in WW and W6 that may be related to the role of IGF-1 at the pre-puberty and puberty stages. Also higher performance of p3 animals in W9, YW and GSN, and p1 animal in GNY may be related to the PIT-1 role in post-puberty.

Molecular characterization of Ethiopian indigenous goat populations

Six Ethiopian indigenous goat populations viz. Gumuz, Agew, Begia-Medir, Bati, Abergelle, and Central Abergelle were genotyped for 15 microsatellite markers recommended by Food and Agriculture Organization of the United Nations and International Society for Animal Genetics. A total of 158 individual goats were tested to assess genetic variations within and between the goat populations in the Amhara Region of Ethiopia. The markers revealed 100% polymorphism across six goat populations indicating the presence of genetic diversity, which is an important variable to measure genetic variability within and between populations. The mean observed and expected heterozygosity values ranged from 0.56 (Central Abergelle) to 0.68 (Bati) and 0.59 (Abergelle) to 0.69 (Agew goat), respectively. The lowest genetic distance was observed between Begia-Medir and Central Abergelle (0.039), and the largest distances between Agew and Abergelle (0.140) and Gumuz and Abergelle (0.169). Neighbor-joining and the unweighted pair group method with arithmetic mean methods with bootstrap value of 1,000 was used which grouped the six goat populations into two major groups viz. the Abergelle goat cluster as one group and the Agew, Gumuz, Bati, Begia-Medir, and Central Abergelle goats as the second group. In our study, the obtained higher total variation within the goat populations (95%) confirms a close relatedness of the studied goat ecotypes, which might have happened due to the existence of uncontrolled animal breeding strategies resulting from uncontrolled movement of animals through various market routes and agricultural extension systems. The study contributed to the genetic characterization of Ethiopian indigenous goat populations and demonstrated the usefulness of the 15 microsatellite makers for biodiversity studies in goats.