James and the Giant Corn Genetics: Studying the Source Code of Nature

Update: PolITiGenomics just posted a piece on the corn genome as well.

You know I could keep talking about the maize genome all day (and I may very well do just that), but what are other bloggers saying about the most complicated plant genome ever published, of second most important single species for feeding people around the world? (Clearly I’m not at all excited)

Mary over at Openhelix is excited about the study of differences in the number of copies of genomes between different maize plants, including genes that are found in some corn, but completely missing in others, as well as the fact 85% of the corn genome is made up of transposons (selfish dna).

A lot of bloggers seem to be surprised that corn has more genes than humans, which means they must have missed the original shock when arabidopsis, one of the smaller, least exciting (at least to non-biologists) plants out there, was the first plant to have its genome sequenced and beat out humans for number of genes ~27,000 to ~23,000.  Shhh… nobody tell those people that rice has over 40,000 genes or they’ll REALLY develop an inferiority complex. Plant genomes are excitingly complicated. It’s one of the reasons I love studying them so much.

I’ve also found some people who seem to think different colors of corn are from different species:

blue and dark/black corn are the original ones and the more nutrius , i belive yellow is the domisticated one and favourd by farmers for its “easy” growth

I’m pretty sure people like that are not reading my blog, but I thought I’d warn the people who do read that this meme is alive and multiplying in the wild*

But the most refreshing views I’ve come across in my search for reactions to the publication of the maize genome are exemplified in this title from Corn Commentary: “Let’s Hear a Cheer for the Guys in Lab Coats!” Since I personally had nothing to do with the sequencing of the maize genome, I hope no one will take it as self congratulation to say: I completely agree! (As if you couldn’t tell my views on the subject from the wave of posts I’m putting up today.)

*For the record, color of corn is controlled by a handful of genes, and often the change of even a single gene can result is drastically different colors. Most of the corn grown in the US today is yellow as a result of a gene that promotes the accumulation of beta-carotene in the kernals themselves. Breeders introgressed that version of the gene into most of the corn grown in the US which makes corn marginally more nutritious. It’s basically a much less concentrated version of what happens in golden rice. While normal yellow corn doesn’t make that much difference, breeders are currently developing lines of corn with so much beta carotene they’re bright orange (some of the credit for this work goes to Cornell). If the decades plant breeders spent searching for similiar natural variation in rice had payed off, golden rice would be saving lives right now around the world instead of still being tied up by the incredible scrutiny given to any crop developed using genetic engineering.

A single maize ear with kernals of two colors resulted from different versions of a single gene (c1). Photo credit: MaizeGDB

Yellow and white corn kernals on the same ear. The difference is controlled by a gene named y1.

The fact that these genes have have single letter appreviations followed by the number 1 should give you a sense of just how long ago maize geneticists started studying them. If I go out and discover a cool new phenotype in maize tomorrow, it’d probably end up with a name like rgd17 (my apologies if there already is an rgd17 gene).