Duke Scientists Map 'Silenced Genes'

palegray.net writes "Wired reports on new research into the phenomenon of 'silenced genes', genetic constructs that have no 'partner' in case one goes wrong over the course of your lifetime. Scientists at Duke University have mapped some 200 genes that may 'play a profound role' in the health of the average human. 'Many of the newly found imprinted genes are in regions of chromosomes already linked to the development of obesity, diabetes, cancer and some other major diseases, the researchers reported ... Scientists had thought imprinted genes would account for about 1 percent of the human genome. While scientists must double-check that the newly identified ones are truly silenced, the new map matches that tally.'"

Comments

slashdot summary is terrible.....

[tloh]

From the article, a bit more pertinent background:

Usually, people inherit a copy of each gene from each parent and both copies are active, programmed to do their jobs whenever needed. If one copy of a gene becomes mutated and quits working properly, often the other copy can compensate.

Genetic imprinting knocks out that backup. It means that for some genes, people inherit an active copy only from the mother or only from the father. Molecular signals tell, or "imprint," the copy from the other parent to be silent.

Re:With

[Anonymous Coward]

I believe that understanding epigenetics will have a huge impact on human medicine. If we learn how to turn different genes on and off we could do all sorts of amazing things. It's already clear that a number of health problems are related to having a gene in the wrong state.

machine learning

[Takichi]

On the Duke news site they give more information about how they came to their findings. They mention that they fed data about the sequences of genes known to be imprinted, and likely to be non-imprinted genes into a computer to check for differences. Based on that, they searched for other sequences that resembled the imprinted ones. That's why the results are just good guesses and more research need to be done to determine if they are true positives.

Re:With

[tloh]

As you said, you are not a biologist. Leukemia is a type of cancer, and I specifically excluded cancer in my post. This research may be relevant to cancer (ONLY, in my opinion). However it's not the Holy Grail it is presented as.

If this leads to advancement in the treatment of cancer (even if only cancer), I think many would consider it to be a holy grail enough. But then, to the credit of the article's author, no where in the article did they allude to this research result being a Panacea for all of humanity's ills. I may not have a biology degree (yet) but I don't have to in order to understand the article. However, I'm a bit confused by your comprehension of the article. You seem to be under the impression that an imprinted gene leads to a single affected cell being damaged/killed and that is of no consequence. That's not what the article is talking about at all. Genomic imprinting happens during the formation of gametes which means the entire organism which develops is affected. What is relevant to the article is that the *consequences* of genomic imprinting for an organism which has no insurance policy to handle the environmental influences on it's development. If environmental factors *are* of consequence, you can bet that the effect is not going to be felt by just a single cell or affect just a single gene. In other worlds, if, for example, you diet is to be considered a risk factor, every cell (all containing the same allele of the imprinted genome) in you entire body is going to be subjected to what you eat. But since most diseases are not caused or controlled by a single gene, we can only speak of raised or lowered risk due to the nature of exposure. The article specifically mention that "imprinted genes are in regions of chromosomes already *linked* to the development of obesity, diabetes, cancer and some other major diseases". They never said such are the definitive causes of such diseases.

There are many stem cells in the bone marrow and wiping one of those cells out will not lead to aplasia. And we're talking about millions of cells getting the exact same gene damaged - in theory. Now what are the odds of THAT?

Are we talking about the same stem cells? If a damaged progenitor cell gives rise to mature lineage cells of the circulatory system, it seems certain that the odds of those decedents all having the same gene damage are 100%. If environmental exposure can cause one cell to acquire genetic damage, the odds are that is not an isolated occurrence and you will end up with defective cells from far more than just one mutated stem cell. Health hazards would not called that if they affect only one or two cells would they?

....and becomes less functional, but this has nothing to do with malfunctioning genes.

In another post, you made mention of being "able to identify non-desirable traits that are more likely to be passed on to offspring" and "inherited a non-functional gene for the GLUT-2 glucose transporter". If this is your notion of gene imprinting, you don't really understand the process at all. Imprinting is an epigentic process (as someone else has already mentioned). It is a non-sequential manipulation of gene expression that doesn't alter the gene itself. The affected gene is turned on/off through methylation but is otherwise completely intact and functional. In fact, in each generation, the old imprints are "erased" in the gamete-producing cells and the chromosomes of developing gametes are newly imprinted according to the sex of the individual. For a given species, the imprinting pattern always follow a consistent maternal/paternal line generation after generation. But nowhere does the process of imprinting destroy or damage the gene itself.