Parasite international open-access, peer-reviewed, online journal publishing high quality papers on all aspects of human and animal parasitology

The aim of this study was to analyze the relationship between polymorphism of the MHC-DRB1/DQB1 gene and its resistance to Cystic Echinococcosis (C.E), as well as to screen out the molecular genetic marker of antiechinococcosis in Chinese Merino sheep. The MHCII-DRB1/DQB1 exon 2 was amplified by polymerase chain reaction (PCR) from DNA samples of healthy and hydatidosis sheep. PCR products were characterized by restriction fragment length polymorphism (RFLP) technique. Five restriction enzymes (Mval, HaeIII, SacI, SacII, and Hin1I) were employed to cut DRB1, while seven restriction enzymes (MroxI, ScaI, SacII, NciI, TaqI, Mval, and HaeIII) were employed to cut DQB1.Results showed that frequencies of patterns Mvalbb (P<0.01), SacIab in DRB1 exon 2 (P<0.05), and TaqIaa, HaeIIInn (P<0.01) in DQB1 exon 2 were significantly higher in the healthy group compared with the C.E individuals, which implied that there was a strong association between these genotypes and hydatidosis resistance or susceptibility. Chi-square test showed that individuals with the genic haplotype DRB1-SacIab/DRB1-Mvalbb/DQB1-TaqIaa/DQB1-HaeIIInn (P<0.01) were relatively resistant to C.E, while individuals with the genic haplotypes DRB1-Mvalbc/DQB1-Mvalyy/DQB1-TaqIab/DQB1-HaeIIImn (P<0.01) and DRB1-Mvalbb/DQB1-Mvalcc/DQB1-TaqIab/DQB1-HaeIIImn (P<0.01) were more susceptible to C.E. In addition, to confirm these results, a fielding experiment was performed with Chinese Merino sheep which were artificially infected withE.g. The result was in accordance with the results of the first study. In conclusion, MHC-DRB1/DQB1 exon 2 plays an important role as resistant to C.E in Chinese Merino sheep. In addition, the molecular genetic marker of antiechinococcosis (DRB1-SacIab/DRB1-Mvalbb/DQB1-TaqIaa/DQB1-HaeIIInn) was screened out in Chinese Merino sheep.

Semi-quantitative RT-PCR was applied to investigate the developmental patterns of GH-R, IGF-1 and IGF-IR mRNA expression in skin of two sheep breeds. One breed was the first filial generation (F1) of Romilly Hillys x Merino of China (Xinjiang Agricultural Reclamation line) wool sheep, and the other was Kazak hair sheep. 18S rRNA was used as the internal standard. Sheep were weighed and wool and skin samples were collected at different times. Results showed that body weight increased rapidly during 30-135 days but slowed during 135-255 days. Wool growth increased gradually during 30-135 days, degreased till 180 days of age, but rebounded thereafter. Overall, body weight and developmental patterns of wool growth was not significant different between hair and wool sheep. GH-R mRNA expression in the skin of hair sheep increased significantly during 30-90 days, peaked at 90 days of age (P<0.05), then declined signifi cantly (P<0.05). GH-R mRNA expression in the skin of wool sheep increased significantly until 135 days of age (P<0.01) and then decreased significantly (P<0.01). The peak level was higher in the wool sheep than the hair sheep. The expression of cantly IGF-1 mRNA and IGF-IR mRNA in the skin of hair sheep increased during 30-90 days, then declined significantly (P<0.01). The expression of IGF-1 mRNA and IGF-IR mRNA in the skin of wool sheep were high at birth and then reduced gradually. The IGF-1 mRNA expression in the skin of hair sheep reached its peak at 90 days of age, and was significant higher than that of wool sheep. The expression of GH-R, IGF-1 and IGF-IR mRNA in skin of hair sheep was higher than that of wool sheep before 90 days of age, but was lower after that. The results suggest that GH-R, IGF-1 and IGF-IR mRNA expression in the skin of sheep follows specific developmental patterns, and different patterns exist between the two breeds.

The mammalian Y chromosome plays a critical role in spermatogenesis. However, the exact functions of each gene on the Y chromosome have not been completely elucidated, due, in part, to difficulties in gene targeting analysis of the Y chromosome. The zinc finger protein, Y-linked (ZFY) gene was first proposed to be a sex determination factor, although its function in spermatogenesis has recently been elucidated. Nevertheless, ZFY gene targeting analysis has not been performed to date. In the present study, RNA interference (RNAi) was used to generate ZFY-interrupted Hu sheep by injecting short hairpin RNA (shRNA) into round spermatids. The resulting spermatozoa exhibited abnormal sperm morphology, including spermatozoa without tails and others with head and tail abnormalities. Quantitative real-time polymerase chain reaction analysis showed that ZFY mRNA expression was decreased significantly in Hu sheep with interrupted ZFY compared with wild-type Hu sheep. The sex ratio of lambs also exhibited a bias towards females. Together, the experimental strategy and findings of the present study reveal that ZFY also functions in spermatogenesis in Hu sheep and facilitate the use of RNAi in the control of sex in Hu sheep.