Tuesday, November 11, 2008

A Great Time for Genetics

This is a great time to be involved in genetics because there is so much change happening in all areas of genetics from real basic stuff such as the nature of the gene to how genes figure into evolution.

There is a great series of articles in the New York Times science section that you ought to look at to get some sense of the excitement today in genetics.

The first article by Carl Zimmer looks at the genome, all the DNA found in our chromosomes. The article focuses not so much on the classical protein coding genes that every one thinks about the rather the 99% of the DNA in our cells, that is not well understood. The article also delves in to what do we mean by a gene any way? The concept started with Mendel who not knowing about DNA called genes factors. During most of the 20th century we taught that genes code for proteins but now we understand that genes are a lot weirder than the cut and dry protein coding segments of DNA we thought they were.

The next article by Andrew Pollack looks at RNA and the many roles of this molecule in genetics. We used to think that there were three types of RNA, ribosomal, transcript and messenger but now we understand that there are other types of RNA that are involved in the regulation of genes and their expression. Some of these RNA’s may revolutionize the way we treat certain diseases.

The next article in the series by Benedict Carey looks at new hypothesis about mental illness which says that certain types of mental illness might result in the conflict of genes from a person’s parents.

The notion that genes may be in conflict with one another may seem odd, but here is an example. We know that there are genetic elements that make extra copies of themselves in the genome or bias the results of meiosis so that more of them get passed on to the offspring even at the expense of the fitness of the individual organism. It turns out that in response to these sorts of “selfish elements”, other genes suppress the activity of the “selfish genes” . Gene conflict also plays out in the male parent’s vs the female parent’s genes during development and the article discusses an interesting example of that.

The notion of gene conflict in an evolutionary sense is well established for certain type of genes but if this idea is true it would mean that certain types of mental illness are not so much due to what genes you have but which genes “win” the gene conflict and are expressed.

These articles may seem quite different but they all have a couple of common threads. First of all they illustrate the dynamic nature of science and how scientists rather than wanting to defend simplistic views of science are constantly challenging established science as new empirical evidence becomes available. Second these articles each in their own way get at the limitations of basic concepts and levels of analysis used in science. In the first article, the gene concept, which started out with a gene as an indivisible factor like a bead on a string, has morphed into a series of somewhat different concepts to the point where you can’t always tell where one gene begins and another end.

The second article lays waste to the idea that everything in the cell is controlled somehow by the DNA working with proteins. RNA’s also are involved in determining which genes are expressed and which are not. So here our original understanding of RNA again has been altered due to some very interesting discoveries, some of which were quite accidental.

The 3rd article takes the role of genes in mental illness and for that matter lots of other situations a step beyond what genes are present as being important, but to a view point that within an individual genes may be in “conflict”, so our notions of genotype (typically defined as the specific combination of genes an individual has) turn out to be way too simplified. Not only that the notion of gene conflict introduces a whole shadow world with in an individual organism so that the individual become like a house divided…divided by an evolutionary conflict between the organism’s own genes.

So check these articles out and let me know what you think.
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