Hemant has a summary of the Atheist Alliance International Convention 2007. I should have been there! Maybe next year I’ll be invited to speak — it sounds like maybe some people would like me to speak…
As soon as the picture of PZ was up, there were cheers from the crowd. (PZ, you had fans at the convention!)
Vox populi!
All of us mammals have pretty much the same set of genes, yet obviously there have to be some significant differences to differentiate a man from a mouse. What we currently think is a major source of morphological diversity is in the cis regulatory regions; that is, stretches of DNA outside the actual coding region of the gene that are responsible for switching the gene on and off. We might all have hair, but where we differ is when and where mice and men grow it on their bodies, and that is under the control of these regulatory elements.
A new paper by Fondon and Garner suggests that there is another source of variation between individuals: tandem repeats. Tandem repeats are short lengths of DNA that are repeated multiple times within a gene, anywhere from a handful of copies to more than a hundred. They are also called VNTRs, or variable number tandem repeats, because different individuals within a population may have different numbers of repeats. These VNTRs are relatively easy to detect with molecular tools, and we know that populations (humans included) may carry a large reservoir of different numbers of repeats, but what exactly the differences do has never been clear. One person might carry 3 tandem repeats in a particular gene, while her neighbor might bear 15, with no obvious differences between them that can be traced to that particular gene. So the question is what, if anything, does having a different number of tandem repeats do to an organism?
Like these.
Here’s a strategy to make money from your expertise!
There is some bad news, though.
Here’s a website of mutating pictures, a collection of images made with a splatter of scattered triangles. Your job is to browse through them and score them for how much they resemble a face — which isn’t easy. If I stare at any random pile of symmetrical shadings, they all start to look like faces to me.
Anyway, pictures that get higher scores produce more progeny, with slight mutations, in the next round of picture generation. You can see where this is going…
Casey Luskin has to be a bit of an embarrassment to the IDists…at least, he would be, if the IDists had anyone competent with whom to compare him. I tore down a previous example of Luskin’s incompetence at genetics, and now he’s gone and done it again. He complains about an article by Richard Dawkins that explains how gene duplication and divergence are processes that lead to the evolution of new information in the genome. Luskin, who I suspect has never taken a single biology class in his life, thinks he can rebut the story. He fails miserably in everything except revealing his own ignorance.
It’s quite a long-winded piece of blithering nonsense, so I’m going to focus on just three objections.
Cosma has to go and show off with a magisterial demonstration of why he is the smartest man on the internet: he’s written an exceptionally thorough description of heritability and IQ. It’s not a light read (statistics and genetics!), but it’s probably the most informative thing I’ve read in a month or more.
I’m sure I’m going to have to read it a few more times before I’ve absorbed it all.
The neurobiology of intelligence
Where do people get the idea that intelligence has a biological basis? Oh yeah, from those geneticists, whose research has shown that intelligence levels can be inherited. One fairly new development for researching intelligence is through the conduction of brain imaging studies.
Recently, two neuroscientists by the names of Richard Haier of the University of California, Irvine and Rex Jung of the University of New Mexico, compiled a review of 37 such intelligence imaging studies. With this data, and current neurobiology studies that indicate intelligence is a measure of how well information travels through the brain, Haier and Jung formulated what they call the Parieto-Frontal Integration Theory (P-FIT). This theory identifies the stations of the brain, chiefly found in the frontal and parietal lobes, that network to produce intelligent information processing. So, whether you are smart or stupid depends, in part, on differences in connections between, and composition of, specific areas of the brain.
Haier and Jung have made many contributions to intelligence research. They discovered that it is unlikely that a single “intelligence center” exists, as the regions of the brain related to general intelligence are dispersed throughout the brain. In another study, general intelligence levels between the sexes were determined to have essentially no disparity, and yet their neural structures are different, with women having more white matter and men having more gray. This indicates that intelligence levels are independent of brain design.
Of course, can all of this just be taken with a grain of salt, because how does one really measure intelligence?
Chris Clarke callously infected me with a meme. I’m supposed to answer these five questions.
An interesting animal I had
An interesting animal I ate
An interesting animal in the Museum
An interesting thing I did with or to an animal
An interesting animal in its natural habitat
My first thought was, “Dude! These are awfully personal questions. Why are you asking for these intimate details of my sex life?” But then I noticed that he brought up my little friend Snowball (you may not want to read that), and all of his stories were about non-human animals. Oh. Never mind. That’s completely different.
Or maybe not so different…
It’s been quite busy last week. Despite the Neurobiology class didn’t meet that week, my other classes kept my hands full. I blame it on two exams and a paper due during the week of Homecoming.
Since I don’t have any new thoughts on Neurobiology, let’s see what can be dug up from my Biochemistry class. For the lab, I wrote my paper of Desulforedoxen. Its job is reducing sulfates. You can look it up at JMol using “1DHG” as the code.
I found this protein very interesting. In class, we had learned about the driving forces for tertiary structure in proteins: H-bonding, hydrophobic/Vanderwal’s, salt bridges, and disulfide bonds between Cystine residues. Upon examining Desulforedoxen, I learned that Cystines were capable of more than just S-S bonding. With four Cystines clustered nearby each other in the tertiary structure, an iron atom sits tetrahedrally bonded to the four sulfurs. While I bet it is a major player in tertiary structure, it just reeks of active site. Since the transition metal, and its neighboring sulfurs, have ‘D’ orbitals, this looks like it’s capable of something that can’t easily be performed in a test tube.
I’ll be a lot of you already know that this can happen in proteins. For me, it was learning it by observation instead of in lecture, that was fun. Moments like that have made it well worth it to go into biology. It’s also cool how such lesser-used amino acids have more than one purpose that they can serve in cells.
Note: the article I read about this protein said that it had iron bonded to the sulfur. When I looked it up in JMol, it was instead bonded to mercury. Weird. An abstract of the article I used can be found here. Anyways, just washing my hands so I don’t fall victim to the inconsistencies-lynch-mob. Have a nice day.
