Direct Evidence on the Contribution of a Missense Mutation in GDF9 to Variation in Ovulation Rate of Finnsheep

peer-reviewedThe Finnish Landrace (Finnsheep) is a well known high-prolificacy sheep breed and has been used in many countries as a source of genetic material to increase fecundity of local breeds. Analyses to date have indicated that mutations with a large effect on ovulation rate are not responsible for the exceptional prolificacy of Finnsheep. The objectives of this study were to ascertain if: 1) any of 12 known mutations with large effects on ovulation rate in sheep, or 2) any other DNA sequence variants within the candidate genes GDF9 and BMP15 are implicated in the high prolificacy of the Finnish Landrace breed; using material from lines developed by divergent selection on ovulation rate. Genotyping results showed that none of 12 known mutations (FecBB, FecXB, FecXG, FecXGR, FecXH, FecXI, FecXL, FecXO, FecXR, FecGE, FecGH, or FecGT) were present in a sample of 108 Finnsheep and, thus, do not contribute to the exceptional prolificacy of the breed. However, DNA sequence analysis of GDF9 identified a previously known mutation, V371M, whose frequency differed significantly (P<0.001) between High and Low ovulation rate lines. While analysis of ovulation rate data for Finnsheep failed to establish a significant association between this trait and V371M, analysis of data on Belclare sheep revealed a significant association between V371M and ovulation rate (P<0.01). Ewes that were heterozygous for V371M exhibited increased ovulation rate (+0.17, s.e. 0.080; P<0.05) compared to wild type and the effect was non-additive (ovulation rate of heterozygotes was significantly lower (P<0.01) than the mean of the homozygotes). This finding brings to 13 the number of mutations that have large effects on ovulation rate in sheep and to 5, including FecBB, FecGE, FecXO and FecXGR, the number of mutations within the TGFβ superfamily with a positive effect on prolificacy in the homozygous state

Fertility Care Services

The Catholic Church calls married couples to responsible parenthood; this includes both openness to new human life and the avoidance of pregnancy when serious reasons present themselves. Natural methods of family planning respect the dignity of the person and the integrity of the sexual act. They treat fertility as a natural process rather than a disease. Natural family planning (NFP) works with a woman’s menstrual cycle; it uses awareness of fertile and infertile times to achieve or avoid pregnancy and allows married couples, through their awareness, to respect and maintain both the unitive and the procreative aspects of the sexual act. In this chapter, Dr. Fehring points out that the benefits of using NFP are “a better understanding of fertility, increased communication, self- mastery of sexual desires, greater generosity toward new human life, and openness to God’s will.” He also explores the history of fertility awareness methods, their scientific basis, and their efficacy. He discusses some medical side benefits of tracking fertility: it can reveal abnormalities and is an aid in the assessment and treatment of infertility. Daily discussion of fertility enhances communication between spouses. Periods of abstinence, while difficult at times, also provide opportunities for the couple to develop nonsexual expressions of intimacy, thereby enhancing mutual respect and married life. The teaching and use of NFP is an effective way of promoting the culture of life.—Editors

Studies on the sperm reservoir of the pig oviduct

During sperm transport in the female pig a proportion of spermatozoa are arrested, often for 24 h or more, in a particular segment of the utero-tubal junction (UTJ) and the adjacent tubal isthmus, where a sperm reservoir (SR) is built up. The SR maintains, via its lining epithelium and the fluid it produces, sperm viability pre-ovulation. It also controls the release of potentially fertilising spermatozoa so that only a small sub-population reaches the site of fertilisation, thus diminishing the risk of polyspermy. In vitro research has focused on sperm binding as the main mechanism of sperm storage, sperm release and modulation of capacitation, but little attention has hitherto been paid to the isthmic oviductal fluid (IOF), its composition and the control of capacitation in vivo. This thesis aimed to study the intra-luminal milieu of the SR in sexually cycling gilts and sows, its contents of glycosaminoglycans (GAGs) — particularly of the non-sulphated hyaluronan (HA) — and the presence and expression of the specific HA receptor CD44 and of HA synthases. Both non-inseminated (controls) and inseminated animals were studied during specific moments of oestrus, in relation to spontaneous ovulation. Ultimately, the study aimed to determine the capacitation status of SR-stored spermatozoa and the effect of IOF and HA on capacitation of the SR-stored spermatozoa. The results showed that SR-stored spermatozoa are entrapped in a mucus-like IOF pre-ovulation. This IOF contains fluctuating levels of sulphated GAGs and HA. Hyaluronan is synthesised in the lining epithelium by HA synthase 3 (has3). Both the ligand and the specific HA-receptor CD44 were particularly present in the deep furrows of the SR, where most spermatozoa are trapped. Massive sperm capacitation does not occur in vivo in the porcine SR under spontaneous standing oestrus, particularly during pre- and peri-ovulation, but SR spermatozoa capacitate if exposed to the effector bicarbonate. Exposure of SR spermatozoa to IOF (or its component HA) in vitro was seen to reverse the bicarbonate influence during pre- and peri-ovulation but to potentiate capacitation post-ovulation, suggesting an active role for the intra-tubal fluid and/or HA in modulating sperm capacitation in pigs. The findings support the concept that the oviductal SR keeps the potentially fertile spermatozoa viable and uncapacitated during their pre-ovulatory arrest. The findings may help improve sperm preparation protocols for porcine in vitro fertilisation (IVF) and preservation of boar semen