Saturday, September 13, 2008

Lethal Alleles and Cool Animals They Create

A lot of you (well, a lot of the few people who are bored enough to read this) are familiar with the Manx cat example of lethal alleles: in feline genetics, having one copy of the gene gives you no tail, having two copies means you have no cat. The picture shows another example, which I had not previously heard of: the Chinese crested dog. Again, one copy of the bald and ugly gene will result in an ugly dog. Two copies of the bald and ugly gene will result in an ugly expired dog fetus. That being said, here's a genetics problem I adapted from a classic probability problem:

Two Manx cats have 4 babies, of which dies at birth due to combination of fatal alleles. The 3 surviving kittens are placed into boxes by the owner, who noted whether each kitten had a tail or not. You really like cats with tails. In fact, Manx cats freak you out. The owner allows you to select one unopened box, and he selects another box that he knows contains a Manx cat. He opens the box and shows you the cat. Should you open the box you selected, or select another box?

Saturday, September 6, 2008

Shirt Idea

So, I'm planning on distributing shirts at the Activities Fair and I need some help! The design is mostly plagiarized off of other shirts on the internet. So, PLEASE feel free to comment on the following:

Yea or Nay?
STAPH, Biology Students Association, or nothing on the back?
Color: should I go another color? Do we have too many purple n' white shirts? Maybe invert the colors?

What would you pay for the shirt on the range of $5-10? (Answer on the poll!)

What ratio of S, M, L, XL (XXL??) should I get?

Is this even a good idea?

Tuesday, September 2, 2008

Obama/McCain Science Policies

For those folk who happen to be both politically- and scientifically-minded, here's a pretty thorough and even-handed look at McCain and Obama's records, plans, and opinions on science policy:


For European viewers, the map above shows how genetic markers can be used to find your ancestors' countries of origin. The accompanying article:

Monday, September 1, 2008

One Heart, One Ho, Two Dead Husbands, and Major Histocompatibility Complexes

Between painting benches and going to the paint store three times (I managed to get the wrong spray paint three times), I ran across an interesting article on CNN:

For those of you too busy enjoying your lonely summer to check out this wild story of heart transplants, high expectations, and suicidal love (but not too busy to read this post), here’s a short, gritty summary:

Girl wants money. Girl meets boy. Girl marries boy. Boy can’t get her enough money. Boy off’s himself. Boy’s heart goes to old dude. Old dude meets girl. Old dude marries girl. Old dude can’t take it either. Bang!

So, what’s this have to do with biology? Well, there’s this segment of the genome found in all people that codes for proteins that identify self and non-self. Known as the Major Histocompatibility Complex, this gene family codes for proteins that play a big role in immunity. Interestingly enough, these genes also influence mate selection: having a different MHC is a huge turn-on for most animals. The evolutionary reasons behind this are pretty straightforward, as mixing up MHCs can result in offspring with tougher immune systems, similar to the way having a horse breed with a donkey results in a mule (who will be smarter, stronger, and less of a burden on daddy’s banking account—no need to buy mule condoms…which are probably huge and not biodegradable—I digress).

Anyways, due to its role in determining self and nonself, a donor and receiver’s degree of MHC similarity is also important for successful matching of transplant organs. Similar MHC’s correlate positively with high success rates. Since the transplant was a remarkably good match (Suicidal Spouse #2 survived for over a decade), we can guess that Suicidal Spouse #1 and #2 had similar MHC’s. A little math can show the rest of the story:

Let the MHC’s of Suicidal Spouse #1 and #2 = α and β, respectively.
Let Twice-Widowed Chick = ♀

By Law of Organ Transplant Success: α = β
By Law of Attraction: α ≠ ♀
Transitive Property: β ≠ ♀
Observed: α + ♀ = Death
Therefore: β + ♀ = Death

So, the moral of the story is: be careful.