Thursday, April 10, 2008

Evolution Class

I am a biology major. I believe in evolution. I think it's an amazingly beautiful and elegant concept. It's also very mysterious because we know very little about it. I will write a separate post on the amazing-ness that is evolution, but this one is dedicated to one of my professors.

I'm taking a class this semester on genetics, development, and evolution, and how these three things tie together. My professor for that class is so cute! She's so accomplished and established in her field - she knows all the big shots in the evolution-development (henceforth called evo-devo) field. She's also a great human being - in fact, many of the girls in my class aspire to be like her. That says something.

After class she sometimes randomly emails us things. Like this:
I can't help but wonder, how did we got here from speciation again? Nonetheless . . .

7 legged, hermaphrodite lamb

"Bhagat, they discovered, had one of the world's most bizarre medical conditions - fetus in fetu"
Or this other time:
Walking back from class, I finally thought of a good example:

Given the name "phenotype" we discussed, possible "genotypes" are Sean and Shawn. If a mutation is a change of one letter, it is much easier to get to a new phenotype of "Dean" if you start at Sean rather than Shawn.

Have a nice weekend!
Okay, this email requires a bit of background. Genotype is what our genes actually are, and phenotypes is what's actually expressed or seen. The two don't always go hand-in-hand per se. For example, you may have the genes for blue eyes but actually have brown eyes. Your genotype includes the genes for blue eyes, but your phenotype is brown eyes.

Now, this email refers to a phenomenon called "developmental systems drift" (or DSD for short). Way back in the 1990s, people thought that similar developmental pathways used the same genes. For example, the development of the complex eye from a handful of cells only used a certain set of genetic mechanisms. But under DSD, a developmental pathway could result from 2 or more different genetic mechanisms.

So in her example, the names Sean and Shawn are pronounced the same. The pronunciation of these words is the phenotype, while the actual spelling of the names is the genotype. We were talking about how DSD could lead to phenotypic variation. So, a new phenotype would result when a mutation caused both the spelling and pronunciation to change, such as when Sean changed into Dean and the pronunciation along with it.

So that's that. It's a really cool concept, because it's totally contrary to logic and makes you go "wtf" when talking about evolution. Oh! She went to a "fly meeting" in San Diego last week (She studies the fruit fly Drosophila melanogaster, btw). Anyway, she met the person who created PLoS (or the Public Library of Science), and she got a T-shirt from him that says "Drosophila loves PLoS." She was like, "I wasn't thinking of ever wearing this outside my house . . ." We making her wear that to class on Tuesday. Apparently, this guy rented a beach house for his lab during the meeting. And someone there was from Austria and knew how to make sausages from scratch.

That's all for now. One of the next posts will be on evolution. And how sweet it is.

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