Wednesday, November 11, 2009

Building a tastier cow.....Or why beef researchers have all the fun

So, this blog claims to have a science aspect, so I thought I'd throw one out there. I have been doing a lot of reading of the scientific literature in the last few weeks, to get a baseline of information on genetic linkage maps in non-model species. Wow, big words right off the bat. Let me explain. In genetics one can build what are called linkage maps. What these are are sets of "markers" which move around together between individuals, that is, when you breed two individuals together, they exchange genetic material, and this is reflected in their offspring. A linkage group is a set of "markers" (usually genes) from one parent that all move together (i.e. A B and C are all from mom (they are linked), then d and E are from dad). Using this information, scientists can build maps of the genome, and subsequently they can use these maps link specific traits (i.e., brown hair) to specific locations on the genome.

Agriculture scientists are really interested in these maps for their animals. By linking specific traits to specific genes, they can do more selective breeding and "build a better animal". Here is where a big disclaimer comes in:
Let me explain. A GMO is an organism, which has DNA (genes) from a DIFFERENT organism, inserted into it's genome (i.e., fish DNA in a tomato). This is a controversial subject and not one I'm going to go into at this time. The process I am talking about is just selective breeding, what humans have been carrying out with livestock etc for thousands of years. Having a genetic map just allows breeding selection to be more targeted, but the end result, in this case, is still cows with only cow DNA.

Moving on to the fun part. So I have been reading all this agriculture literature, and a lot has been pretty generic (i.e., We have built the first map for Animal X) but then I found this gem...
"Association of selected SNP with carcass and taste panel assessed meat quality traits in a commercial population of Aberdeen Angus-sired beef cattle"
what caught my eye was the "taste panel." Really, taste panel, is that a quantitative trait? Apparently it is. I won't reproduce sections of the article here (it is actually an Open Access Journal, so if you are interested, just Google the title). The short of it is, this group selectively bred some cattle with known meat traits. They then scored the meat quality. Some of the scores used an instrument called a tenderometer...I don't know what that is but it sounds cool. But here is the best part. Part of the research was assembling a panel of taste testers, cooking up the steaks, and having the testers score them on flavor, likablity, best odor etc, in an attempt to link some known genetic markers to these traits. Clearly, beef researchers have all the fun. They didn't just do this once, they had "49 taste panel sittings. Taste panel members participated in one to 37 panels with an average of eight sittings per panelist" So they averaged eight steaks a piece, with at least one lucky guy got 37 STEAKS.

In summary, I actually really like this study, a lot. I like the concept of using genetic tools to simply breed a better organism, rather than resorting to GMO processes. But I have three remaining questions: (1) Is taste really a quantitative trait? What if I don't like beef, or just that cut of beef? (2)Nothing ruins a good steak faster than poor cooking. I know they had a "method" but really, how much did the cooking process play in the results. Should they have recruited Gordon Ramsey to be a study member? and finally (3) Wow Beef researchers have all the fun, how can incorporate a "taste panel" into my research?!?

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