Identical Twins Aren't Identical?

Now here's an interesting topic; one that I have wanted to write a post about and now have the lovely time to do it!

For those who don't already know, a report was published in the February issue of
the American Journal of Human Genetics (AJHG) concerning genetic differences between identical (i.e. monozygotic - arriving from one fertilized egg) twins. Weird. Identical twins are supposed to be identical through and through, right? Isn't that why they're called identical? Well, maybe not. I suppose that is pushing it a little.

Anyway, Carl Bruder, a geneticist from the University of Alabama at Birmingham, and colleagues compared the genomes of 19 sets of adult identical twins. What they found was that these people differed subtly from their twin in what's called, copy number variation (CNV) of their genes.

As Wikipedia states, CNV's refer to:

"differences in the number of copies of a particular gene present in the genome of an individual . . . Some people have deletions of some genes on only one chromosome while other people have multiple copies of some genes."

People typically have two copies of each gene within their genome, because they inherit one copy from each parent. Yet at various genome sites copy number variation occurs. One would expect that monzygotic twins would resemble each other in the amount of CNV's that occur in their genomes. Since the "identical" twins from the above study differed in genetic copy number variants, they aren't 100 % identical!

It's all very interesting. And I think such findings may trigger important implications to consider for further psychological research. In fact, I learned about this study through class discussion in a personality research class and am frankly surprised that it hasn't received as much attention as I thought it would through the various media outlets.

What's one of the major issues most everyone will learn about in any psychology course? Well how about the battle between nature and nurture? Everything's a nature/nurture problem. And the common way to decide the influence of nature on a psychological attribute is to conduct a twin study. The logic behind a twin study is that identical twins should be most related to each other, as compared to dizygotic twins, non-twin siblings and strangers. Therefore differences between monozygotic twins on, say, a personality variable (and we do occasionally find these types of differences) aught to be attributed to environmental influences. But if identical twins are not really genetically identical, then how do we know that a personality difference isn't genetic? Now the AJHG report does not completely destroy the picture created by twin study results. Monozygotic twins are still highly similar; again, the differences in CNV's are subtle. Yet the paper does add the implication that an observed personality difference cannot automatically be attributed to the environment.

Oh well, if you want to read more about it, there is a Scientific American article about it, as well you can visit the AJHG site are read the original article. Go check it out! Very cool stuff!

Happy Birthday to me!

picture by explodingdog

Graduation and other stuff . . .

Well graduation was this past Sunday for the College of William & Mary. As you can see, I decided to attend, and I brought my wife along. It was nice and short. And though there was some celebration, it ain't over yet! All my class requirements are completed, but there's still that little thing we call a thesis that needs to be defended. I have until July 18th to defend my thesis, which is plenty of time so I don't expect to run into any problems. But until then I suppose I can't officially consider myself an MA. My wife on the other hand has completed everything, including her thesis, and her graduation from VCU is this Saturday. Fun stuff.

So now we basically have about two months before we move to Lexington, KY and start our doctoral programs at the University of Kentucky. This is an exciting time for us. Of course, we don't have much to do right now. I do have thesis work to complete, as well I'm still working on a few other side research projects. Yet I still feel that I have a lot of free time on my hands. Part of this free time I plan to spend writing (both blog and academic writing). As well, I have started a writing schedule (under the advice of my future grad advisor) and I hope to use these two months to get used to scheduled writing. Hopefully then I will break my binge writing habits, haha.

As for the blog, I'm making myself the goal of at least three posts a week, though it'll be great if I can get to posting daliy. I let myself slack too much this past semester, so I need to make up for it. Anyways, more on that later! Congratulations to all my friends and colleagues who are now fellow graduates! Yea!

On another note, here's a collection of links to keep you busy. Each has to do with psychological science in some way or another:

* Firstly, here's a newly launched website called Personality and Social Psychology Comments. As you can guess from the title, it's an online database of comments on published papers in the areas of personality and social psychology. Here's a brief description of PSPC:

"In order to advance as a scientific field, we argue that personality and social psychology should be characterized by cumulative knowledge as well as a constant questioning and discussion about what has been previously established. To incorporate such an ideal, previous data and unpublished research should be far more accessible than it is today.

We believe that there is a great deal of well-conducted research such as replications, extensions of previous studies, and null findings that never reach the stage of publication. Thus, valuable information never gets accessible to the scientific community.

Most of all, however, we believe that scientific enterprise should be open and critical and there should be a space to express criticism and other viewpoints. PSPC is meant to provide a forum for these issues and hopefully function as a resource for researchers conducting reviews and meta-analyses as well."

PSPC seems like it could be a pretty useful tool, but no one has bothered to submit any comments yet. I'm not sure whether it's because the word just hasn't gotten out yet or what. But if it starts to garner some popularity, I imagine it's usefulness will become more apparent . . . especially those comments focusing on null findings.

* The second item concerns a society called, Psychologists for Social Responsibility. This is the first time that I have heard about them, though the group was founded 25 years ago. I found out about them through a social psychology listserv. It's basically a group that uses psychological knowledge to promote peace and social justice. I took a gander at their website. I suppose that if you are into peace or political psychology, this might be an interesting group to look at/consider.

* Finally, my last item concerns a new essay that Steven Pinker has just written in the New Republic. It concerns the concept of dignity, its uselessness in terms of bioethics, and how it's being used to stall the progress of basic scientific and medical research. It's a good essay, brief and to the point. Go check it out!

Roll up to the Magical Memory Tour?

Now here's something cool that I read about in the April edition of Observer. Psychologists from the Leeds Memory Group, at the University of Leeds, are conducting an online survey that aims to create the "biggest database of 'autobiographical memories' ever attempted."

How are they doing this? Interestingly, they are asking people to blog about their memories of the Beatles! And anyone who has a memory related to the Beatles can participate. You can find their online study here at the Magical Memory Tour.

On their website, you can blog about your own memories of the Beatles, as well as check out the memories of other people. You can even find out which albums or songs evoke the most positive or negative memories. You can even check out the top ten most viewed Beatles associations (so far, number one is John Lennon - In Memoriam).

The researchers hope to explore "how experiences from our lives might be associated with music, personality, and the public perception of the Beatles." Seems like a pretty cool project to me! Check it out!