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Bloggers on the Maize Genome

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)

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Maize: The Genome Sequence Itself

The corn genome is ~2.4 gigabases (2.4 billion As, Ts, Cs, and Gs) divided among ten chromosomes. The genome of sorghum, the most closely related species with a sequences genome to maize, is also divided into ten chromosomes, but it’s only less than 800 megabases long, approximately a third the size of maize.

What accounts for the size different? Well since their divergence, maize went through a whole genome duplication, doubling it’s genome to twenty chromosomes (which have since been reduced to ten again, as pieces of chromosomes broke apart and stuck to each other*). Since then a bunch of deletions have also occurred, so only sometimes like 20-30% of the genes from the ancestor of maize and sorghum can still be found in both duplicated regions. Clearly the genome duplication of maize is not responsibly (or at least not solely responsible) for the the enormous size of the maize genome.

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About the Maize Genome Paper

Looking at the maize genome paper in isolation it’d be easy to wonder what all the fuss was about. The paper itself is only four pages long with (plus a page of citations), with two figures, and as awesome as figure 1 is (and it really is very, VERY awesome), it doesn’t seem like an lot for a project that represents the work of more than 150 authors over four years. But the real fruits of the maize genome project are the sequences that can be found on either or and additional exciting research it is already enabling. And as the result of a quirk the way genome sequence is released to the research community, we can already get a sense of some of that other research.

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The Family Tree Of Corn

Branches not to scale. Tree designed in Mesquite.
Branches lengths not remotely to scale. Tree designed in Mesquite.
This family tree shows the relationship of a few of the species in the grass family tree that I think people might be most familiar with. Genomes that were published before today are marked in green (there were only two, sorghum and rice), the maize genome which was just published today is marked in yellow, and brachypodium (which you shouldn’t feel at ALL bad if you haven’t heard of) is marked in grey as its genome project is in the final stages (a draft assembly was released to the public last winter) so it’ll probably be the next grass genome to be published. After that I’m less sure, I know there’s a foxtail millet genome project, but I don’t have any idea how far along the process of genome sequencing, assembly and annotation the genome project is.
What’s important to know about the relationship of the sequenced grasses?

Genetics Plants

Patrick Schnable on the Maize Genome

Let me know if you have any trouble with the embedded video. The embedding code from ISU doesn’t seem to play well with wordpress.

I’ve got several posts on the maize genome coming out scheduled to go up later today. Living on the west coast (not to mention having a circadian clock that seems convinced I should actually be living on Honolulu time) it’s the only way to get information up in time for morning readers in most of the US.

Anyway, hopefully some of what I’ve written makes sense (I’ll be running a lot of long computational jobs at work so I’ll have plenty of time to answer questions in the comment sections about all the stuff I’ve written that doubtless makes no sense at all). But to start us off this morning, how about a short (<4 minutes) video from Patrick Schnable one of the two lead authors on the maize genome paper. After four years of talking about the corn genome project as well as it’s challenges and benefits, one gets very good at it.*

[flowplayer src=]

See the video in it’s original context here. I’m assuming since ISU provides embedding code they’re ok with me showing it here.

*Fair disclosure, there are important reasons I may be biased in my evaluation.