Presence of SNPs in GDF9 mRNA of Iranian Afshari sheep

Background: Multiple births occur frequently in some Iranian sheep breeds, while infertility scarcely occurs. Mutation detection in major fecundity genes has been explored in most of Iranian sheep flocks over the last decade. However, previously reported single nucleotide polymorphisms [SNPs] for bone morphogenetic protein receptor-[BMPR]-1B and growth differentiation factor] GDF9[known to affect fertility have not been detected. This study was conducted to assess whether any significant mutations in GDF9 were extracted from slaughtered ewe ovaries of Iranian Afshari sheep breed

Materials and Methods: Ovaries defined as poor, fair, and excellent quality based on external visual appearance of follicles were used for histology and RNA extraction processes. High quality RNAs underwent reverse transcriptase-polymerase chain reaction [RT-PCR] from GDF9 mRNA, and the products sequenced

Results: No streak ovaries, which are considered indicators of infertility due to homozygocity for some mutations in GDF9 and BMP15, were found. Sequencing results from GDF9 cDNA showed that G2 [C471T], G3 [G477A], and G4 [G721A] mutations were observed from 1, 4, and 1 out of 12 ewes, respectively. Though all 3 mutations were previously reported, this is the first report on their presence in Iranian breeds. The first and second mutations do not alter the amino acids, while G4 is a non-conservative mutation leading to E241K in the prohormone

Conclusion: As the G4 mutation was observed only in ovaries defined superficially as top quality, it could be considered as one of reasons for higher ovulation rate in some sheep. Furthermore since multiple mutations were observed in some cases, it might be possible that combinations of minor mutations in GDF9 and BMP15 interact to affect fecundity in some Iranian sheep breeds

Effect of ovarian cyclic status on in vitro embryo production in cattle

The relationship between cyclic status of cattle ovaries on in vitro embryo development up to the blastocyst stage was investigated. Cattle ovaries were collected immediately after slaughter and divided into three categories based on their cyclic status, which included: 1. the presence of a large follicle [LF], 2. the presence of a corpus luteum [CL] and 3. ovaries without LF or CL [WLCF]. Oocytes of these ovaries were obtained and used for in vitro maturation and fertilization. Presumptive zygotes were then cultured up to the blastocyst stage in synthetic oviductal fluid culture medium. There were no significant differences between cleavage rates of the three groups. The rate of embryos in the compact morula stage for the CL group was 48.2% which was significantly higher than the related rate of the LF group [36.6%], but non-significantly higher than that of the ST group [45.7%]. The highest blastocyst rate belonged to the CL group [54.6%] which was significantly greater than the WLCF group [32.9%] and non-significantly higher than the LF group [52.4%]. There was no significant difference in blastocyst rates in the CL and LF groups. Preselection of oocyte donor ovaries containing a CL or LF can be used as a feasible and noninvasive criterion to obtain the most competent oocytes capable of development to the blastocyst stage