No abstract

The genetic diversity and phylogenetic relationships of 108 individual sheep from three Turkish sheep breeds (Kivircik, Gökçeada, and Sakiz) were studied using RAPD analysis. Polymorphisms within and between populations were assayed using 15 random primers, and 82 loci were amplified ranging from 250 to 2,500 bp. The percentage of polymorphic loci was found to be 80.49, 78.05, and 73.17%, for Kivircik, Gökçeada, and Sakiz sheep breeds, respectively. Total genetic diversity was 0.2265, and the average coefficient of genetic differentiation was 0.1181. Genetically, the Gökçeada breed was more closely related to the Sakiz breed than to the Kivircik breed.

The genetic polymorphism of the beta-lactoglobulin gene was investigated in three native Turkish sheep breeds. The study was carried out on 108 sheep (29 Kivircik, 38 Gökçeada, and 41 Sakiz) by means of PCR-RFLP methods. Two genetic variants (A and B) and three genotypes (AA, AB, and BB) of beta-lactoglobulin have been identified. The gene frequencies of beta-LG A and B were 0.7759 and 0.2241 in Kivircik, 0.7632 and 0.2368 in Gökçeada, and 0.9756 and 0.0244 in Sakiz breeds, respectively. The populations were in Hardy-Weinberg equilibrium in all samples from the three breeds.

Milk samples from 203 Holstein cows were phenotyped for genetic variants αs1‐casein, β‐casein, κ‐casein and β‐lactoglobulin using starch‐gel electrophoresis. All of the four milk protein loci exhibited polymorphism with allele frequencies of 0.862 ± 0.017 for αs1‐casein B, 0.966 ± 0.0009 for β‐casein A, 0.712 ± 0.0224 for κ‐casein A and 0.567 ± 0.0245 for β‐lactoglobulin B. The mean heterozygosity estimated over all the four milk protein loci was 0.3015. Genetic equilibrium was observed among all of the loci investigated, except κ‐casein. Chi‐squared tests revealed that there was no significant linkage among studied milk protein phenotypes.

A total of 135 unrelated sheep from nine Turkish native sheep breeds (Daglıc, Kivircik, Imroz, Chios, Morkaraman, Ivesi, Hemsin, Karayaka and Akkaraman) were investigated to determinate the maternal genetic diversity using a sequence of a 531-bp segment of the mtDNA control region. Analysis of the mtDNA control region sequence revealed 63 haplotypes and 53 polymorphic sites. Haplotype diversity, nucleotide diversity and the average number of nucleotide differences were estimated to be 0.9496 ± 0.011, 0.01407 ± 0.00060 and 7.456, respectively. The sequence analysis also revealed high level of genetic diversity among the native Turkish breeds. These breeds were grouped into three major maternal haplogroups: A, B and C, with one animal belonging from the Akkaraman breed to the rare haplogroup E. Irregular shape of mismatch distribution of haplogroup C could be an indicator that haplogroup C may represent different haplogroups. Contrarily to previous studies carried out on Turkish native breeds, majority of animals grouped in haplogroup A in the present study. This result and the irregular shape of mismatch curve of haplogroup C indicate that genetic structure of Turkish native sheep breeds could be more complicated than it is thought.