Molecular genetics of cattle muscularity.
| dc.contributor.advisor | Bottema, Cynthia Denise Klemme | en |
| dc.contributor.advisor | Pitchford, Wayne Scott | en |
| dc.contributor.author | Novianti, Irida | en |
| dc.contributor.school | School of Animal and Veterinary Sciences | en |
| dc.date.issued | 2011 | en |
| dc.description.abstract | Genetic improvement is a goal of most livestock industries and molecular information can contribute to the accuracy of selection and hence rate of genetic improvement. The aim of this study was to obtain molecular information that can be used to assist selection for muscularity in cattle. Quantitative trait loci (QTL) mapping for traits related to muscularity (but not growth), candidate gene identification and association studies between the candidate genes and the muscularity related traits were conducted. Interactions between the candidate genes and myostatin, a gene known to have a major role on muscularity in cattle, were also examined. Genotype and phenotype data from the JS Davies cattle gene mapping project were used for this study. QTL for muscularity related traits across 3 sire families were mapped in 366 double back cross progeny from pure Limousin (carrying the myostatin F94L variant) and Jersey cows. Cohort and breed were fitted in the model. A model that included the myostatin F94L genotype was also fitted to identify chromosomal regions in which gene(s) that may be epistatic with myostatin reside. Covariates were used to obtain QTL for carcass traits related to muscularity and not related to growth. In total, all the QTL mapped to 15 regions on 11 chromosomes (BTA 1, 2, 3, 4, 5, 8, 9, 11, 13, 14 and 17). In terms of the traits that best define muscularity, the QTL on cattle chromosomes 2, 3 and 17 were of greatest interest. Fitting the myostatin F94L genotype in the model indicated that the QTL on chromosome 17 are likely to be epistatic with myostatin. Six candidate genes were selected based on the QTL results of the study herein and previous studies on the same population. The genes were activin receptor type 1 (ACVR1), smad nuclear interacting protein 1 (SNIP1), similar to follistatin-like 5 (FSTL5), transforming growth factor β receptor 3 (TGFBR3), insulin like growth factor 1 (IGF1) and follistatin (FST). DNA variants of FSTL5 were associated with the traits of interest but there was no interaction with myostatin. DNA variants in TGFBR3 and SNIP1 had no direct effect on muscularity traits but there were significant interactions with myostatin. For IGF1 and FST, their DNA variants had direct effects on muscularity related traits and there were significant interactions with myostatin. FST SNP7 and the interaction between IGF1 SNP2 and myostatin had the most significant effects on muscularity related traits (P<0.01). The results of this study showed that there are genes affecting muscularity not related to growth and some of these interact epistatically with myostatin. Furthermore, potential markers for muscularity have been discovered (eg. FST). Further studies in larger cattle populations need to be undertaken to confirm the results herein before these markers can be utilised commercially. | en |
| dc.description.dissertation | Thesis (M.Ag.Sc.) -- University of Adelaide, School of Animal and Veterinary Sciences, 2011 | en |
| dc.identifier.uri | http://hdl.handle.net/2440/69482 | |
| dc.provenance | Copyright material removed from digital thesis. See print copy in University of Adelaide Library for full text. | en |
| dc.subject | cattle; muscularity; genetics; retail yield; myostatin; follistatin | en |
| dc.title | Molecular genetics of cattle muscularity. | en |
| dc.type | Thesis | en |