Yamburgan Shorthorns - Genestar & Breedplan Information

GeneSTAR Marbling is a DNA diagnostic test for a major gene associated with marbling. It is the first gene marker for a production trait in beef cattle. The test enables cattle breeders to select individuals that carry one or two copies of the favorable allele.

What is GeneSTAR Marbling ?

GeneSTAR Marbling is a DNA-based diagnostic test for a major gene associated with marbling in beef cattle.
The test distinguishes between alleles of the Thyroglobulin gene. Thyroglobulin is involved in the pathway that creates fat cells within muscle fibres as energy storages. The gene exists in a variety of forms and one of these forms has been shown in CSIRO research, with funding from Meat and Livestock Australia (MLA), to be associated with increased marbling in cattle on lot-fed (200 days) feeding programs. These studies showed an association both within families and across breeds without reference to pedigree information. An association was demonstrated in Angus, Shorthorn and Wagyu cattle.
Recent studies examined the frequency of the favourable allele in elite sires from a range of breeds. The frequency of the gene was higher in those breeds known for marbling compared with those where marbling is not a high priority trait.

How is the test done ?

The laboratory analysis tests for a specific gene sequence and is based on a restriction site that occurs within the gene sequence. The test is a PCR-based (Polymerase Chain Reaction) RFLP (Restriction Fragment Length Polymorphism) test. In its current format the test separation of alleles occurs on a gel with the result visualized by staining with ethidium bromide.
GeneStar Marbling tests for the presence of one copy or two copies of the favourable form of the Thyroglobulin gene.

Was there a difference in the effect in other studies?

The difference between zero-stars and two-star animals has been consistent in all studies with a significant increase in marbling score and quality grade.

"The Genestar marbling gene is largely hidden in the total (polygenic) expression of marbling or IMF% from all the marbling genes". Does this mean that it has no correlation or is 'disconnected' from all the other genes that affect marbling?

This statement was made after the initial results were published by CSIRO which showed that the effect was only significant in two-star animals. More recent results have shown that there is also a significant effect of one star. It is not possible to make assumptions about the relationship between this gene and other genes affecting marbling at this stage.

It means that it should be possible to construct matings that take advantage of both the benefits of GeneSTAR marbling and EPDs.

How many genes or alleles affect marbling?

There are many genes that effect marbling, however, there is a small number (less than 10) that have significant enough effects to be individually distinguished. A number of studies have shown 2-5 major genes effecting marbling.

Do your studies show any correlation between rib fat, rump fat, internal fat, and marbling?

Three of the studies have examined correlated effects of GeneSTAR marbling on other carcass traits, the fourth study is yet to report on this. The studies so far have all shown no effect on any trait other that marbling score and quality grade. The carcass traits examined include carcass weight, rib fat, rump fat, rib eye area.

The correlations between the traits themselves have not been reported but there is numerous literature estimates of these associations.

The GeneSTAR technology is in its earliest applications, however, it is the future of genetic improvement in the beef industry. There will be more of these tests available in the future. Indeed Genetic Solutions expects to release another gene marker before the end of the year. We have an active R&D program that is developing more of these tests and we are negotiating with R&D groups to evaluate their markers for their commercial utility. The focus of our company is to determine what gene markers have value at the commercial level and make these tests available to the broader industry in a cost:effective manner.

About GeneSTAR Tenderness

GeneSTAR Tenderness is a DNA-based test for variants of the bovine calpastatin gene. The test detects two different forms of the gene- one is associated with increased tenderness and the other with increased toughness. Calpastatin is a naturally occurring enzyme that inhibits the normal tenderizing of meat during post mortem aging.

This test was introduced to the beef cattle industry internationally in November 2002.

GeneSTAR® Tenderness was developed from gene marker research conducted by the Cattle and Beef Quality Cooperative Research Centre (CRC), CSIRO Livestock Industries and Meat and Livestock Australia. The team that made the breakthrough was led by Dr Bill Barendse who also led the team that discovered the gene marker behind GeneSTAR® Marbling, the first ever commercial DNA marker test for a production trait.

There are large differences in genotype frequencies between the breeds. Angus, Hereford, Shorthorn and Murray Grey breeds have relatively high frequencies of 2-STAR animals, the tender genotype. The Brahman breed shows a lower frequency of the 2-STAR with less than half the frequency of the British breeds and also a higher level of 1-STARs.

However the fact that there were 0-STAR (the tough genotype) animals in each British breed tested indicates that all breeds can make use of this test.

The test has application at the seedstock and commercial level though initially the priority for application is the seedstock sector. By selecting for a higher frequency of 2-STAR animals, inconsistency and variation in tenderness due to genetics can be reduced over time and eventually eliminated.

BREEDPLAN is a modern genetic evaluation system for beef cattle breeders. It is based in Australia, with clients worldwide. BREEDPLAN offers bull breeders the potential to accelerate genetic progress in their herds, and to provide objective information on stock they sell to commercial breeders.

BREEDPLAN calculates Estimated Breeding Values (EBVs)+ for a range of traits including:

Weight	Fertility	Carcase
Birth weight	Scrotal Size	Carcase weight
200-day milk	Days to Calving	Eye Muscle area
200, 400 and 600-day weight	Gestation length	Fat thickness
Mature cow weight	Calving Ease	Meat Yield %
		Marbling
+(Note: EPDs are calculated for North American clients)

Included in the calculation of EBVs are the animal’s own performance, the performance of known relatives, the heritability of each trait and the relationship between the different traits ie. a world class genetic evaluation model, combining all traits in one analysis.

All breeds of beef cattle in Australia use BREEDPLAN. For most, the BREEDPLAN genetic evaluation system has been integrated with the respective breed association’s pedigree system. Substantial genetic improvement for traits of commercial importance have been demonstrated.

The BREEDPLAN technology is kept at the leading edge by continuous research. The Animal Genetics & Breeding Unit (AGBU) is located on the campus of the University of New England and undertakes the research into the genetic evaluation system. Its budget for this is about $1.5M per annum. (AGBU recently hosted the 6th World Congress in Animal Genetics.) In addition the Beef Quality Co-operative Research Centre at the University of New England undertakes detailed research and field trialing to determine the relationship between genetics and beef quality. This is also used by AGBU to update the BREEDPLAN system, particularly in the carcase area.

Armidale has become a centre for excellence in beef breeding technology. As a result breed societies representing 18 beef breeds have now established their national headquarters in Armidale to be part of this exciting program of beef improvement.

The BREEDPLAN technology is highly regarded in a number of overseas countries where it is made available under licence. It has been adopted as the national beef recording scheme in Australia, New Zealand and Thailand and is also used in the Philippines, USA, Canada, Argentina and the United Kingdom.

Genetic databases for particular breeds in these countries are now being merged to conduct international genetic evaluations. The rationale for this is simple - the larger the population of cattle being evaluated the higher the chance of finding elite genetic material which can then be rapidly disseminated using modern artificial breeding techniques. This will improve the competitiveness of beef production in all co-operating countries.

You can visit www.breedplan.une.edu.au to find out more information. You can also search for individual Santa Gertrudis animals at the Santa Animal EBV enquiry search engine.