Abstract

The Inverdale gene (FecX) is extraordinary. Located on the X- chromosome, it increases ovulation rate in the heterozygous state, but in the homozygote the ewe has undeveloped or "streak" gonads and is sterile. The phenotype is almost certainly due to the action of the gene in early embryonic/foetal development. The Inverdale may be valuable model for investigation of similar phenotypes in other species, especially the human female. Identification of the gene itself will enable substantial progress in understanding mechanisms of ovarian and follicle development. However, even without knowledge of the specific gene function, there are the areas where the phenotype itself may be of real value. Two such areas are the "tumour-like" structures in the homozygote as a model for ovarian tumours and the "steroid-free" environment of the homozygote as a model for investigating the regulation of seasonality in sheep.

PF, Fennessy

Proceedings of the New Zealand Society of Animal Production, Volume 55, , 310-311, 1995