Identification of sequence variation in the oocyte-derived bone morphogenetic protein 15 (BMP15) gene (BMP15) associated with litter size in New Zealand sheep (Ovis aries) breeds.

Advances in the study of reproductive traits indicate that functional variation in fertility genes may be useful for improving sheep fertility. The aim of this study was to search for variation in the bone morphogenetic protein 15 gene (BMP15) and ascertain any association with litter size in purebred Finnish Landrace sheep (n = 148), Finnish Landrace × Texel-cross sheep (n = 45), and composite sheep (of varying breed background; n = 58) from New Zealand (NZ). A 482 bp and 312 bp fragment of exon 1 and 2, respectively, of BMP15 were analysed using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). The additive and dominance effect of BMP15 variation on litter size were estimated using animal and sire models. Two variants (A and B) were detected in exon 1; no sequence variation was detected in exon 2. Variant A had the nucleotide sequence CTT between positions c.31 and c.33, while variant B had a deletion (c.31_33del). The observed frequency for variant A in the Finnish Landrace sheep, Finnish Landrace × Texel-cross sheep and the composite sheep, was 0.77, 0.92, and 0.68, respectively while the frequency of variant B (c.31_33del) was 0.23, 0.08, and 0.32, respectively. An association between litter size and c.31_33del (P < 0.001) was observed in composite sheep. Analysis of more sheep will be required to confirm these results. Litter size did not differ significantly between sheep breeds regardless of the presence/absence of c.31_33del. Results suggested that c.31_33del might be a genetic marker for improving fecundity in some NZ sheep.

Microsatellite Analysis of Genetic Diversity and Population Structure of the Iranian Kurdish Horse.

Native breeds are essential for national stocks and genetic reservoir; therefore, the preservation of indigenous breeds is a key policy priority for countries around the world. Many conservationists would assert that genetic diversity is a prerequisite for adaptive evolution, and preserving genetic diversity will need conservation efforts for the long-term survival of domestic species. This study intended to evaluate the genetic diversity of the Iranian Kurdish horse population based on microsatellite indicators, which can partially prevent it from becoming extinct. Fifty-eight tail hair and blood samples were randomly collected from Kurdistan, Kermanshah, Ilam, West Azerbaijan, Isfahan, Kerman, Hamadan, and Tehran. Genomic DNA extraction was performed by a modified salting out method. The polymerase chain reaction amplification conditions were also separately undertaken for each marker. All microsatellite loci revealed polymorphisms in the studied population. Genetic variation was examined using 12 microsatellite loci (HMS7, HMS3, HMS2, HMS6, ASB2, ASB23, VHL20, HTG10, LEX33, ASB17, AHT4, and AHT5). We found that the means of the observed and effective number of alleles were 7.58 and 4.95, with the minimum and maximum values for each of these indices associated with the loci of HMS2 and ASB17, respectively. Moreover, the mean of observed and expected heterozygosity, polymorphism information content, and Shannon's Information Index of the Iranian Kurdish population were 0.77, 0.78, 0.75, and 1.67, respectively, indicating a high degree of genetic diversity in the entire studied population. More specifically, we acquired a range of new alleles in the Iranian Kurdish horse breed that differed in their genetic structure to those of other Iranian breeds in other studies. This study provides an exciting opportunity to improve our knowledge of genetic information which will be beneficial as a base to identify purebred Kurdish horses for a further Iranian Kurdish horse genetic and breeding program.