Manx Loaghtan is a rare sheep breed indigenous to Isle of Man. Regarding Japanese population, since a small number of founders were introduced, and has been maintained in a small population size, inbreeding depression due to excessive inbreeding is highly concerned.  In order to evaluate the genetic diversities and characterizations of Manx Loaghtan kept in Japan, the population genetic analyses based on 36 microsatellite loci and the statistical genetic analyses based on pedigree information were performed.  The genetic diversity of Japanese Manx Loaghtan population is typically low compared with other sheep breeds.  It seems to be the bottle neck effect caused by the small population size of Japanese Manx Loaghtan population after their introduction.  Moreover, the phylogenetic distinctiveness of this breed in a comparison with the other common sheep breeds in Japan was also shown.  Although Manx Loaghtan as well as the other common breeds are originated in Europe, Manx Loaghtan is belonging to the Northern short-tailed sheep group.  It is possible the result of this study indicates the propagation route of the Northern short-tailed sheep group from their domestication origin to Europe was distinctive from other Western breeds.  Our population genetics and statistical genetic analyses demonstrated that the inbreeding of Japanese population is effectively suppressed by the aggressive outbreeding.  On the other hand, it is also shown that all of the coefficient of inbreeding, coefficient of relationship, and coancestry are increasing year by year.  In order to preserve and maintain Manx Loaghtan in Japan, it is prerequisite to suppress the accumulation of inbreeding coefficient as much as possible.  Therefore, it is important to design the breeding program taking account of genotype information in addition to the current breeding scheme.  Moreover, we suggest the effective utilization of frozen semen domestically stored for maintain the genetic diversity and characteristics through the time.

To clarify the origin and derivation of the Lanping black-bone sheep and Shangri-La sheep (called tentatively in this case) raised in the Yunnan Heights of China, estimation of Nei’s genetic similarity and genetic distance, clustering analysis using the neighbor-joining (NJ) method, the unweighted pair-group method using arithmetic averages (UPGMA) and principal component analysis (PCA) were conducted on the basis of allele frequency data at five loci (TF, ES, HB-β, XP and KE) encoding blood protein and non-protein systems. Different electrophoretic and iondensitometric techniques were used to identify polymorphisms. In this study, 26 local sheep breeds kept in East and South Asia studied up to the present were included for comparison. An unusual frequency distribution of two combined alleles such as the X and P alleles at the HB-βand XP loci, or the B and L alleles at the HB-β and KE loci, which demonstrate the characteristics of the northern Asian sheep group, was observed, clearly verifying that both local sheep belong to a group of northern Asian sheep. Average heterozygosity at five loci of the Lanping blackbone sheep and Shangri-La sheep were estimated to be 0.3346 and 0.4407, respectively. Genetic variability induced from these values corresponded with those of Asian local sheep breeds and populations. Nei’s genetic similarity and genetic distance among different local sheep breeds and populations in East and South Asia showed that the Lanping black-bone sheep were mostly related to the Ninglang black sheep of the Himalayan lineage, and the Shangri-La sheep were comparatively close with the Tong sheep and had genetically high similarity to the MongolChinese lineage. Unrooted and rooted dendrograms deduced from Nei’s genetic distance matrix by the NJ and UPGMA methods and the PCA revealed that the Lanping black-bone sheep were in the same group as the Ninglang black sheep and diverged within the Himalayan lineage. However, the NJ and UPGMA showed that the Shangri-La sheep diverged near the MongolChinese lineage sheep and formed a cluster with them, respectively. The PCA revealed that the sheep were plotted between the Mongol-Chinese and Tibetan lineages. These findings suggest that the Lanping black-bone sheep are akin to the Ninglang black sheep and the Shangri-La sheep consist chiefly of the Mongolian lineage, and the Tibetan lineage participates in them, corresponding to a hybrid population of sheep from the both lineages.