Teosintes are a puzzlebox of genes

Teosinte is a so-called primitive version of corn. Basically it’s corn’s version of our monkey, but corn and teosinte can still interbreed. To a corn breeder, teosinte is a puzzle box of genes that have been lost from maize cultivars. What secrets wait for us to discover? We could find disease resistance, drought resistance, improved nutrients… we only have to find the genes.

To date, there haven’t been many studies on what useful traits hide in teosintes. There have been studies in Mexico on their local corn varieties, and on Native American varieties, but fewer than you would think. This week, I’m embarking on an exciting study that, to my knowledge, no one has done before. I’m going to measure the storage proteins in 55 varieties of the genus Zea. Some are teosintes, some are modern cultivars, some are found only in small plots in places like Mexico.
I’m hoping that some of the varieties have storage proteins that are really different from the ones found in modern corn. Modern corn has been bred for yield (and yield it does) but has pretty much no nutritional value. Hopefully some of these varieties will have lots of amino acids that are essential for humans, cattle, pigs, and chickens. I can find the responsible genes, then use them to improve modern lines. Then, instead of growing for quantity, we can grow for quality!
The anti-GM crowd has brought up the issue of gene flow. They say that genes like BT could spread via pollen to non-transgenic crops, including rare cultivars and even wild teosintes. It’s true, it has happened, but very little. The irony is that modern varieties contain many mutations that aren’t found in nature. Modern non-GM corn is just as strange and different as GM corn, and its pollen is just as likely to drift on a breeze. It doesn’t matter much, because a hybrid plant is much more likely to loose a new gene over subsequent generations than to keep it, unless selective pressure is involved. Even if the transgene is retained, it doesn’t turn the plant into something new, as the gene can just be bred back out again if desired.
While I’m on the subject of new genes, I’d like to share two interesting articles that talk about plant breeding via radiation. It’s been done for decades now, but strangely, hasn’t met any resistance. This is surprising, because genetic engineering is confined to one or a few genes, while radiation could change anything, so is inherently riskier. Check out “Useful Mutants, Bred with Radiation” from the NY Times, and “GMOs: Making the Earth Say Beans,” by an awesome female geneticist working on improving stress resistance in crops. She worked with Barbara McClintock!
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  1. Just wanted to share a neat article on the domestication of teosinte: http://sfmatheson.blogspot.com/2007/10/they-selected-teosinteand-got-corn.html“ rel=”nofollow”>They selected teosinte…and got corn. Excellent! The author uses teosinte and maize as an example of evolution, and provides many links to how teosinte has changed in response to selection.

    via the new blog http://clashingculture.wordpress.com/2008/06/01/how-can-you-tell-if-a-scientist-is-a-christian/“ rel=”nofollow”>Clashing Cultures

  2. […] a problem I’m hoping to help alleviate. I’m screening two relatives of maize, the grasses teosinte and tripsicum, for interesting seed storage proteins. My studies so far have shown that the […]

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