In this section:
Molecular biology
Research and development seeks knowledge of the underlying genetic control of trait performance at a gene/DNA level, with a view to supplementation of the conventional tools available for livestock improvement based on quantitative genetics. Outcomes and services fall into one or more of the following categories:
Gene function – Analysis of the function of genes in relevant tissue samples (e.g. muscle, skin) from animals in both research and commercial flocks / herds. Information is delivered via analysis of the function of single “candidate” genes likely to have causative roles in establishment of phenotype, using advanced quantitative Reverse Transcription – Polymerase Chain Reaction (qRT-PCR) technology.
Gene discovery - Analysis of global gene function to establish involvement of known gene pathways or to discover new genes with previously uncharacterised roles in development of phenotype. Delivery is via interrogation of available DNA microarrays with samples prepared from whole tissue.
Linkage of gene function with phenotype - Analysis of gene function in available mutants and in genotypic (EBV) or phenotypic extremes selected from highly characterised research flocks enables linkage of specific genetics with particular phenotypic outcomes. Use of both single gene analysis and global gene function profiling is employed to deliver this outcome and will assist development of gene marker tests that select commercially valuable genetics.
Development of gene analysis tools - Improvement of gene analysis protocols and approaches, development of new systems enabling high throughput sample analysis and bioinformatics tools to facilitate more accurate data analysis all enhance delivery of the services described.
To improve livestock production, classical genetic analysis seeks to identify quality trait loci (QTLs) which may be positively selected using specific breeding strategies. A significant advance has been provided by Molecular Biology, being the ability to identify, isolate and study the role of individual genes responsible for QTL-related phenotypes. Moreover, this has enabled identification of DNA sequence markers (eg microsatellites and single nucleotide polymorphisms - SNPs) associated with specific loci and has augmented DNA marker assisted selection (MAS) strategies. Indeed, parentage at specific genetic loci can readily be followed during breeding regimes. Microsatellite analysis has recently been used to confirm the clonal origin of the cloned lamb Matilda, produced by SARDI at Turretfield Research Centre.
In addition to the study of normal gene function in specific body locations, the effect of environmental factors (weather, nutrition, other factors related to husbandry practises etc) upon gene function may also be determined. Testing of gene expression patterns in the ovine skin and wool follicle and bovine skeletal muscle in response to various nutritional treatments exemplify experiments on-going in the Molecular Biology Laboratory.
For further information, please contact:
Dr. C. Simon Bawden
Molecular Biology Group
SARDI Livestock Systems
