Genetic markers significantly associated with growth, leanness and meat quality are now available to all U.S. pork producers.

The Iowa State University Research Foundation has signed a licensing agreement with GeneSeek of Lincoln, Neb., that licenses the use of DNA markers in four genes. All of these markers have been previously tested and have been commercially validated by a large pig breeding company.

The first gene marker is MC4R and it controls growth and leanness. Producers and breeders can choose from a "fast" growth form of the gene or a "lean/efficient growth" form of the gene. Effects translate into three less days to to market weight, on average, for animals carrying two identical forms of the growth genetic trait, or allele, compared to those carrying identical forms of the lean allele. 

Pigs homozygous for the lean allele have 8 percent less backfat and eat significantly less feed. This technology will allow breeders to choose the characteristic, growth or leanness that they consider best for their program. These results have been well validated and are effective in all breeds tested to date, except the Hampshire breed.

The second gene marker is PRKAG3. Producers and breeders can select animals having the high pH and better meat color form of the gene. Animals having this beneficial genotype have a pH of nearly 0.1 higher in their loin and ham samples than those animals that are homozygous for the non-beneficial allele. Effects are seen in all major breeds.

The third gene marker is CAST, a gene that affects tenderness and meat quality.  Producers can test and select those animals that are likely to produce more tender meat and improved meat quality.

The fourth gene marker is HMGA1, which is highly associated with backfat and lean growth. Producers can test and select animals which are likely to be leaner and produce offspring that are leaner.

The effect of these genes is additive and these genes can be maximized by using them in combination. Using all four would be beneficial for overall line development to reduce days to market, improve leanness and meat quality. A combination of MC4R (growth allele) and HMGA1 could be used for growth and backfat improvement only, or MC4R (lean allele) and HMGA1 could be used together for significant leanness in breeding stock. Finally, PRKAG3 and CAST could be used in combination to improve meat quality. The opportunities are there for breeders and producers to develop the best multi-gene combination for their lines.
 
"More DNA markers and DNA marker technology are not too far down the road," says Mark Boggess, director of animal science for the National Pork Board. 

NPB was instrumental in the international effort to sequence the swine genome and is sponsoring research to develop additional genomic technologies for the pork industry. "The four markers made available by Iowa State University precede the current effort to sequence the swine genome, but they are an indication of how this research can be applicable on the farm," says Boggess. "Included in our research priorities is a groundbreaking study pigs' ability resist or better tolerate disease agents, specifically porcine reproductive and respiratory syndrome virus." 

Source: National Pork Board