JOPLIN, Mo. (Aug. 31, 2011) — Differences drive genetic selection. Turns out, it’s also differences that are enabling the industry to harness the power of genomics before knowing what all of the genes are or what they do.
“There are at least 22,000 genes in the bovine genome, and we don’t know what most of them do,” explained Jerry Taylor at the Applied Reproductive Strategies for Beef Cattle (ARSBC) conference in Joplin, Mo. Taylor is professor and Wurdack Chair in Animal Genomics at the University of Missouri (MU).
For instance, contrary to popular dogma just a few years ago, Taylor explained, “There are hundreds and thousands of marbling genes, not just one or two.” The same goes for other traits.
“What we do know is that they’re full of differences,” Taylor said. “Every genome is different than every other genome.” Think of the genome being all of the different genes and gene combinations that comprise an individual.
One way to identify the differences between genomes is by identifying what are known as single nucleotide polymorphisms (SNPs). These differences can be used within a breed population to estimate the breeding value of animals.
Think of it this way: If you try to guess the exact weight of each steer in a pen, you’ll likely be wrong most of the time. Estimate the average weight of steers in the pen and you’ll likely be closer to being correct.
Likewise, in broad unscientific terms, averaging across SNPs, predicting the genetic merit for a specific trait, is more accurate than depending on a couple of genes known to be associated with the trait.
These genomic differences identified with SNPs are used today to estimate what is termed the molecular breeding value (MBV) for various traits in an individual animal within a breed population. The MBV added to current expected progeny differences (EPDs) increases their accuracy. Young animals with no progeny can have EPD accuracies similar to if they’d had already produced progeny.
This is powerful stuff, though a far cry from the original notion that by this time in history every cattle gene and gene interaction would be known. Ultimately, that may be the case. In the meantime, though, Taylor explained that the use of SNPs for predicting breeding value — and the technology allowing fast and accurate assays of them — are leading producers out of what he terms the trough of disillusion.
All new technologies tend to follow the course of something known as Gartner’s Hype Cycle, Taylor said. Introduction of new technology is followed by a rapid rise of inflated expectations, followed by a rapid decline into the trough of disillusionment as it becomes obvious that achieving the promise will take longer and be more complicated than initially thought. That’s followed by the slope of enlightenment where new opportunities are found on the way to fulfilling the promise. That’s the point where Taylor said cattle genomics is at today.
There’s more current opportunity, too.
“The only thing stopping us from having MBVs for production, carcass, feed efficiency and heifer pregnancy rate right now is the cost of the 50K assay,” Taylor said. The assay he refers to is the technology that allows evaluation a DNA sample for 50,000 or so SNPs fast and accurately. “The technology exists today, but I don’t think we can sell it to you for the right price.”
Taylor spoke during Wednesday's ARSBC session focused on the genomic and economic considerations of producing high-quality cattle. For more information, visit the Newsroom at www.appliedreprostrategies.com to view the PowerPoint slides submitted by Taylor to accompany his presentation. Audio of the presentation will be available soon.
Complete coverage of the symposium will be available online at www.appliedreprostrategies.com. Compiled by Angus Productions Inc. (API), the site is made possible through sponsorship by the Beef Reproductive Task Force, SEK Genetics, and liveauctions.tv. Coverage includes summaries of the speaker presentations, PowerPoints, proceedings and audio.
Editor's Note: This article was written under contract or by staff of Angus Productions Inc. (API), which claims copyright to this article. It may not be published or redistributed without the express permission of API, publisher of the Angus Journal, Angus Beef Bulletin, Angus e-List and Angus Beef Bulletin EXTRA. To request reprint permission and guidelines, contact Shauna Rose Hermel, editor, at 816-383-5270.