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

January 14, 2010

The Newly Published Soybean Genome and Fractionation

Here’s the key statistic: The maize genome paper estimated that roughly a quarter of maize genes are currently retained as duplicate pairs from maize’s whole genome duplication, while the soybean paper estimates just over half of soybean genes are similarly retained after soybean’s (apparently slightly older) duplication. <– had it buried at the end of this, but figured it’d be more fun to start out with something cool.

But first of all, let’s do this the right way this time. Here’s the paper in Nature describing the soybean genome. Here’s one of the places you can download the entire sequence from. Hopefully that establishes, beyond a reasonable doubt, that the soybean genome has, in fact, been published. (more…)

January 12, 2010

Strawberry Genome Sequenced (Correction included)

Filed under: biology,Genetics,Plants — Tags: , — James @ 3:10 pm

After already needing to correct this post, I must now invalidate the whole thing. Seems I’ve been taken in by a premature press release that was turned into reliable sounding articles on news sites and was then picked up by blogs like mine that took the those sites to be credible sources. It’s a big mess. ::sigh::

Among the many things I’m currently missing at the Plant and Animal Genome conference, in addition to an update on the banana genome I’ve just learned (thanks to Mary over at OpenHelix) that the sequencing of the woodland strawberry genome has been completed!

I don’t know yet if the sequence has been released to the public yet. Either way I can’t find the sequence so I can’t yet comment on the quality of the sequence, or any ancient duplications in the lineage (though we already know it must share the ancient hexaploidy of the rosids, possible all eudicots).

Wild diploid strawberry (left) and domesticated octoploid strawberry (right)

What we do know is that modern domesticated strawberries are octoploid, the result of two recent whole genome duplications, but the woodland strawberry doesn’t have any duplications modern enough to be obvious from cytogenetics, visually looking at chromosomes.

Sequencing a genome is a complicated process but it started out with the work of Janet Slovin, a USDA scientist who created the inbred line* used in sequencing and seems to be the front woman from the project (Janet was kind enough to comment and point out the original article was misleading on this point, check out the link she included as well!), she’s quoted in the linked article.
And if you know how I can get my hands on the sequence please PLEASE, drop me a line at jcs98 (at) jamesandthegiantcorn (dot) com.

January 3, 2010

More Details on Transmissible Cancer of the Tasmanian Devils

Filed under: Genetics — Tags: , , — James @ 8:23 pm

Tasmanian Devil photo: Debbi Long, flickr (click to see photo in original context)

I’ve previously mentioned the disease striking the Tasmanian Devils in a post on genetic bottlenecks:

Even less fortunate are the tasmanian devils who have so little genetic diversity that they are being decimated by a transmissible cancer. After fighting with an infected devil, which has tumors on its face and neck, tiny bits of the cancer will get into an uninfected devil’s wounds, and since the immune system can’t distinguish the foreign cancer cells from the devil’s own cells, the cancer cells reproduce unchecked, the trait that makes normal cancers, produced by mutated versions of our own cells, so deadly. And the solution mentioned in the article, to save the species by protecting 200 individuals, while better than letting them all die, will sacrifice even more genetic variability by subjecting the already inbred devils to a new population (and genetic) bottleneck.

Well now we know even more about the original of the cancer cells responsible for “Devil Facial Tumor Disease” (A truly frightening name). By studying the expression patterns of normal genes and microRNAs, a group of researchers have confirmed once and for all that the cancer cells really are being transmitted from one devil to another because the genes they looked at were identical in sequence in cancer cells taken from 25 different devils. The researchers place the original of the cancer as a more regular (mutation induced) cancer that arose in Tasmanian Devil living approximately two decades ago and even believe that they can identify that first mutated cell as a Schwann cell*. (more…)

January 1, 2010

Feeding birds on a large scale can lead to speciation?

Filed under: biology,evolution,Genetics — Tags: , , — James @ 7:14 pm

From The Hindu:

Humans are inadvertently manipulating bird genetics by innocently providing birds with feeders in winter, according to findings by German researchers. Over less than 30 generations, birds visiting British and European gardens in winter have evolved different-shaped wings and beaks, the scientists say.

In time, they could eventually become a distinct species. The birds breed side-by-side in the same Central European forests, but began to follow different winter migration routes after some discovered rich pickings from humans in Britain.

Eventually they divided into two reproductively separate groups. One continued to fly south for the winter, migrating to Spain to forage for olives and other fruits. The other got into the habit of flying a shorter distance north-west to Britain, where bird-lovers fed them.

If you’re interested and with journal access, here is the scientific paper the story is based on (from current biology).

December 30, 2009

Why I’m so Excited About the Banana Genome

Filed under: biology,evolution,Genetics,Plants — Tags: , , , , — James @ 12:01 pm

The single most consumed fruit in America, yet in the tropics this bananas starchy relatives play an even more vital role in feeding whole nations.

At the Plant and Animal Genome Conference next month (which I really wish I was going to), there will be a workshop on banana genomics, but from the abstract submitted by Carine Charron (h/t to Jeremy at the Agricultural Biodiversity Weblog) I learned that:

The sequencing phase will be completed in early 2010 and automatic annotation will take place during the first semester of 2010.

Why is sequencing the banana genome important? Three reasons: (more…)

December 13, 2009

Panda Genome

Filed under: biology,Genetics — Tags: , , , , — James @ 5:11 pm
Can you imagine how much easier it would be to get funding if you too worked on panda biology?

Can you imagine how much easier it would be to get funding if you too worked on panda biology?

Nature just released a pre-publication copy of a paper detailing the sequencing of the panda genome. The genome was sequenced and assembled using entirely 2nd generation sequencing technologies (specifically the Illumina sequencer) which produced reads that averaged only 53 basepairs long.*

The panda they chose was a three year old female, and they got such resolution (the average individual base pair was sequenced 73 times!) they were even able to identify individual changes in sequence between her two copies of each chromosome.** From this they were able to estimate a difference in the DNA sequence (called a SNP***) occur once every 740 bases which is almost twice the rate of humans. (more…)

December 11, 2009

Stalling

Filed under: evolution,Genetics,Link Posts — James @ 7:48 pm

It was a very long day at work and I have nothing interesting to tell you.

Go check out MAT Kinase and John Hawks‘s posts on how human evolution has been driven by the dietary changes of our relatively recent ancestors, farmers and herders rather than hunter-gatherers. (At least in many cases, it’s quite possible someone reading this blog can trace their ancestry back to human populations that remained hunter-gatherers into the 20th century.)

November 26, 2009

The Cost of the Turkey Genome

Filed under: Genetics,Link Posts — Tags: , , — James @ 6:52 pm

Just to give you a sense of how fast technology is advancing:

Sequencing the maize genome took four years and 30 million dollars. Today Virginia Tech announced the University of Minnesota and themselves had received a $908,000 grant to sequence the Turkey genome in two years. I don’t know how big or complex the turkey genome is, but the idea of sequencing a whole new species for less than a million dollars is still pretty cool.

h/t to 538 they’ve got more cool turkey statistics over there.

November 24, 2009

Summary of the Coverage of the Maize Genome here at J+TGC

Filed under: Genetics,Link Posts,Site Business — Tags: , , — James @ 10:47 am

Summarizing a couple of Virginia Walbot’s ten reasons you should care about the maize genome

Hear one of the lead authors of the maize genome paper explain how and why it was done in under four minutes.

Reviewing the quality of the genome sequence itself.

We can already see research made possible by the maize genome.

How maize fits in the family tree of grasses/grains

Read about how the maize genome project is helping researchers find more genes selected for during the domestication of maize.

Plants have more genes than people, why is this still news

Other people on the web react to the maize genome (also why different colors of corn are not different species)

Corn vs Maize

Filed under: Genetics,research stories,Site Business — Tags: , , — James @ 10:46 am

I use the words basically interchangeably on this site. I know it’s confusing and I at least attempt to pick one and use it all the way through a post (often without success, which I’ll catch, and wince at, days later). The problem is that naturally I use one word or the other depending on context.

The plant in question is studied internationally and while in America “corn” means those cool looking plants that you see me standing in front of one third of the time when you visit this blog, in british english the same word means any grain. I’ve never heard it explicitly said, but I assume the reason the geneticists who study the plant originally called it maize was to avoid confusion from those mixed definitions. It’s also possible “corn” was still considered a slang term back then, and not the sort of name a well educated scientist should be using regardless.

As a result of growing up in the midwest surrounded by corn and getting interested in comparative genomics by way of maize genetics, terms like “corn geneticist” and “corn genome” don’t sound right to my ear and ones like “maize plant” or “maize is selling for $5 a bushel” sound even worse. On the other hand, the sentence “Sequencing the maize genome is going to provide even more powerful tools to corn breeders” sounds fine, but I realize it can be confusing to people whose life experiences are different from my own.*

*An even weirder one: Back when I was still doing science that required writing with pen and paper instead of doing everything on the computer, without thinking about it I’d either cross my sevens or not depending on whether I was writing a number in a scientific context.

A crossed 7. Theoretically this is easier to distinguish from a 1, especially on tassel bags and row stakes that are going to be outside, exposed to the elements for months.

A crossed 7.

Theoretically a crossed 7 is easier to distinguish from a 1, especially on tassel bags and row stakes that are going to be outside, exposed to the elements for months. (And where a mistake has the potential to ruin a year or years of work. It’s not like maize geneticists can run down to Walmart and buy more seeds carrying the genotypes they’ve spent years putting together.)

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