Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2004
Publication Date: 7/25/2004
Citation: Spiller, S.F., Ericsson, S.A., Realivasquez, R., Campbell, W.T., Sterns, K.L., Purdy, P.H., Blackburn, H.D., Dzakuma, J.M. 2004. INHA microsatellite polymorphisms in angora bucks. American Society of Animal Science/American Society of Dairy Science/Poultry Science Association Annual Meeting, July 25-29, 2004, St. Louis, Missouri. Journal of Animal Science 2004. 82(Suppl 1):378.
Interpretive Summary: Genetic mediation and variability of sperm production has been hypothesized, but heritability estimates are low, which makes selection for semen characteristics difficult. This study determined if INHA microsatellite polymorphisms (inhibin) is present in Angora buck DNA. Inhibins exert a negative feedback on the pituitary release of FSH and inhibit spermatogenesis. Variation in the microsatellite polymorphisms was observed across the Angora bucks. The presence of these INHA polymorphisms suggests a range of genetic variation that could be used in selection strategies, although further work is required to identify specific associations between the markers and semen characteristics.
Technical Abstract: Genetic mediation and variability of sperm production has been hypothesized, however previous heritability estimates have always been low, therefore making selection for semen characteristics difficult. The objective of this study was to determine if alpha-inhibin (INHA) microsatellite polymorphisms, a dimeric subunit playing a pivotal inhibitory role in the regulation of spermatogenesis, were present in the DNA of Angora bucks. Inhibins are dimeric molecules composed of an alpha and one of two ß subunits (ßA or ßB) that exert a negative feedback system on the pituitary release of FSH. Using a primer set originally developed to amplify ovine INHA microsatellite polymorphisms, purified DNA from 24 mature Angora bucks was amplified and examined using polymerase chain reaction and electrophoresis. The INHA primer set (forward primer AGCGTGTGAAGCTGGAGAT and reverse primer ACGTGATCACTACCACAGT-ACGGA) produced multiple homozygous and heterozygous banding patterns with varying numbers of base pairs (bp). Homozygous bands were detected at 195 bp (1 hd) and 200 bp (3 hd). The following heterozygous banding patterns (bp) were identified: 185, 215 (2 hd); 195, 200 (1 hd); 195, 225 (1 hd); 195, 240 (1 hd); 200, 225 (4 hd); 200, 230 (1 hd); 205, 220 (1 hd); and 205, 225 (1 hd). No banding was observed in 8 goats. These data demonstrate significant deviations of genotype counts from Hardy-Weinberg equilibrium. The presence of these INHA polymorphisms suggests a range of genetic variation that could be utilized in selection strategies, with further work required to identify specific associations between potential markers and semen characteristics. Key words: Angora, inhibin, activin