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IntroductionTurkey's proximity to domestication centers, along with its climate, topographical pattern, and agricultural structure that is formed according to plant cover, has created an appropriate environment for sheep breeding. Therefore, there are many sheep breeds in various regions and territories (1,2). Although there are many varieties and crossbred populations of sheep breeds in Turkey, 20 sheep breeds have been officially registered by the Ministry of Food, Agriculture, and Livestock (3). Even though Gökçeada (GA), Kıvırcık (KIV), Karacabey Merino (KM), and Sakız (SZ) sheep breeds, which are raised in the western Anatolian and Marmara regions, have a low percentage of native sheep population, each breed has certain significant characteristics. SZ sheep, known for their high fertility and milk production, and GA sheep, known for their milk production and high lamb survival rate, are raised along the coastline of the Aegean region. KIV and KM sheep breeds are known for their meat quality, wool, and meat production and are raised in western Turkey. For the purpose of improving the meat quality and fertility of the sheep population in western Turkey, the SZ and KIV breeds are commonly used in crossbreeding (4).Molecular genetic methods for identifying genetic structure and diversity in farm animals have shown a rapid development in recent years and have become widely used. Various molecular genetic methods have been developed for this purpose. Microsatellites that are specific to DNA regions are more widely used than other methods (5).This study aims to determine the genetic structure of GA and SZ sheep breeds, which are bred on the coastline of the Aegean region, and that of the KIV and KM sheep breeds, which are commonly bred in the Aegean and Marmara regions, by means of microsatellites. The information obtained from this study is based on microsatellite markers and will clarify the genetic relationships between these sheep breeds. It will also be helpful for determining current and future breeding programs and breed management and conservation strategies. Materials and methods Animal resources and DNA isolationThe animal material of the study consisted of a total of 250 animals belonging to GA, KIV, KM, and SZ sheep populations bred in the Aegean and Marmara regions. The origins and sample sizes of these 4 breeds are presented in Table 1. A DNA isolation kit (Applied Biological Materials Inc., Canada) was used for DNA extraction from blood samples.

Scrapie is a lethal neurodegenerative disease of sheep and goats caused by the misfolding of the prion protein. Variants such as M142, D145, S146, H154, Q211, and K222 were experimentally found to increase resistance or extend scrapie incubation period in goats. We aimed to identify polymorphisms in the Afar and Arsi-Bale goat breeds of Ethiopia and computationally assess the effect of variants on prion protein stability. In the present study, four non-synonymous novel polymorphisms G67S, W68R, G69D, and R159H in the first octapeptide repeat and the highly conserved C-terminus globular domain of goat PrP were detected. The resistant genotype, S146, was detected in >50% of the present population. The current study population showed a genetic diversity in Ethiopian goat breeds. In the insilico analysis, the R68 variant was predicted to increase stability while S67, D69, and H159 decrease the stability of prion protein. The new variants in the octapeptide repeat motif were predicted to decrease amyloidogenicity but H159 increased the hotspot sequence amyloidogenic propensity. These novel variants could be the source of conformational flexibility that may trigger the gain or loss of function by prion protein. Further experimental study is required to depict the actual effects of variants on prion protein stability. Prion diseases are lethal neurodegenerative disease of humans and animals caused by the misfolding of prion protein 1. Despite being rare, the diseases are lethal and have resulted in huge animal loss over a course of time in several countries 2. The oldest prion disease is scrapie that affects small ruminants 3,4. Though the exact pathomechanism is not yet known, predisposing genetic variants have been documented in different species 5. A wide range of polymorphisms have been identified in goats either as protective or susceptible alleles. A recent review reported the presence of more than 50 polymorphisms in goat prion protein-coding gene (PRNP) 6. Among the variants, G127S, M142I, H143R, N146S, R154H, Q222K, and S240P are the most common substitutions worldwide 7,8. Similarly, R139S in Algeria 9 , A116V in Tanzania 10 , G134E and Q163P in Turkey 11 and G127A and T193I in Ethiopia 12 were novel (at the time of the report) substitutions discovered in the respective area of study. Alleles such as M142, D145, S146, H154, Q211, and K222 were experimentally found to either extend scrapie incubation period or increase resistance 8,13-16. Experimental studies reported the link between sequence variation in the functional domains of prion protein and scrapie disease development 17,18. Substitutions in the palindrome and glycine-rich motifs were identified to affect amyloid fibril formation 19. Although the C terminal globular domain is often involved in the PrP c to PrP Sc conversion process, octapeptide repeat regions are also known to influence the structural dynamics of prion protein. Insertion or deletion of octapeptide repeat for example, induce disease phenotypes 20. According to the FAOSTAT 2017 report, 3...

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The calpastatin (CAST) gene has a major effect on muscle growth and meat tenderness after slaughter; it is located on the fifth chromosome in sheep. Blood samples were collected from 720 animals in total from Kıvırcık (KIV), Sakız (SZ), Karacabey Merino (KM), and Gökçeada (GA) sheep populations raised in West Anatolia. The PCR products were digested by the restriction endonuclease MspI. Allele frequencies for M and N alleles of the gene were found to be 0.85 and 0.15 in KIV, 0.80 and 0.20 in KM, 0.99 and 0.01 in GA, and 0.34 and 0.66 in SZ sheep, respectively. It was determined that NN genotype frequency was quite lower in KIV (0.04) and KM (0.07) populations than in the SZ breed (0.40). On the other hand, the NN genotype was not observed in the GA population. Populations other than KM were found to be in Hardy-Weinberg equilibrium. In general, allele and genotype frequencies of CAST were similar to those in other studies on different sheep populations. This research is a beginning step for finding candidate genes' effects on meat quantity and quality.