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A New Chip Identifies Important Bovine Genomic Traits

published: March 17th 2009
source: University of Missouri News Service

With help from a new genetic device recently unveiled by a team of animal science researchers, animal breeders may soon be building betters cows that produce more and better beef and tastier profits.

The new genetic tool is called the SNP Chip (pronounced snip chip).

A team of scientists in Missouri, Nebraska and Maryland developed the device to identify DNA markers for economically important traits in livestock, including disease susceptibility, milk production, reproduction and growth. It allows scientists to examine an animal's entire genome to detect variations that cause trait variation in a more efficient and economical way.

Jerry Taylor, professor and Wurdack endowed chair in animal science at the University of Missouri College of Agriculture, Food and Natural Resources, and colleague Curtis Van Tassell at the Agricultural Research Service's Beltsville Agricultural Research Center in Maryland, were members of the team that developed the new genetic identification tool for cattle, formally called the Illumina BovineSNP50 Bead Chip.

Funding for the project came from USDA's Cooperative State Research, Education and Extension Service, Agricultural Research Service and industry partners.

All living organisms contain DNA, the blueprint of life, Taylor said. Within the DNA are chromosomes that house neatly packaged genes. Each gene encodes a protein that performs functions necessary to support life. The genome of an organism is the complete assemblage of all of the chromosomes found in that organism.

Variations within a gene and in elements that control the expression of a gene produce differences in agriculturally important traits, such as the ability to produce more or less milk per day. Like farmers who mix and match the traits of plants to produce larger and more flavorful fruit, animal breeders for centuries have tried to minimize bad traits and maximize good ones through selective breeding. Though breeders have made tremendous strides, without a precise and definitive genetic road map, the process has been somewhat hit or miss.

These genetic variations can be monitored by other differences that lie close by on the same chromosome. Single nucleotide polymorphisms (SNPs) are very useful for this purpose because hundreds of thousands of them can be packaged into a single assay, Taylor said. A SNP is a change in a single location in the DNA structure. Each SNP provides an indirect measure of the nearby genetic variants.

The new bovine assay easily and quickly identifies regions within the bovine genome that harbor variants that cause animals to differ in the outward expression of important traits, allowing scientists to predict an animal's total genetic merit from its SNP profile.