epigenetics

hotspur

I'm not a biologist and I literally only tonight came across the area of epigenetics. I was wondering if any of you biologists could speak to the profundity or otherwise of the emerging findings?

From an outsider's perspective I didn't expect when I woke up this morning to be going to bed with Lamarckianism having been established in my mind as a possibility. Also, if you will excuse the ignorance of my imposing my own discipline on you (psychology), I am interested in any applicability to humans, especially in addiction.

2Scoops

We've known about 'epigenetics' for decades, only under different terminology (x-inactivation, herterochromatin/euchromatin etc.). Essentially involves a higher order of control of gene transcription and DNA structure/integrity via chromatin modifications. Btw, epigenetic modifications are not heritable in the same way as DNA, so Lamarckism is still a non-runner. :pac:

It is quite applicable to humans. I think it would be very likely that substance abuse could result in epigenetic changes that associate with behaviour or phenotype. Not aware of any direct evidence in humans but there is bound to be some animal work performed in this area.

Capt'n Midnight

hotspur wrote: »

when I woke up this morning to be going to bed with Lamarckianism having been established in my mind as a possibility. Also, if you will excuse the ignorance of my imposing my own discipline on you (psychology), I am interested in any applicability to humans, especially in addiction.

When some bacteria are starved they don't have enough energy or nutrients to be able to properly repair their DNA from normal wear and tear (from things like sunlight). This means that they temporarily have a higher than normal mutation rate. They evolve faster if you like.

There is a tiny chance that one of the mutations is beneficial, it might allow they to survive longer with food or maybe it allows them to use a new type of food instead of whatever was in short supply.

If this mutation is then inherited it looks like they evolved in direct response to the stress, when all that happened is that random mutation rate went up temporarily.


Unlike insects, humans have the same DNA in all our cells, what makes an amoeba like white blood cell different to a nerve cell that runs from the brain to the base of your spine or a bone cell is the DNA is expressed differently. How this is done and how to control it are important in stem cell research. In the past stem cell research was done only on undifferentiated embryo cells but now stem cells can be generated from other tissue, apart from bypassing many ethical issues it means a patient could be treated with cells containing their own DNA.

I can't remember offhand but there were effects seen in the grandchildren of Dutch women who starved during pregnancy in 1945.

As for addiction , many things can pass the placenta into an unborn child

Kevster

Out of sheer curiosity, where did you read about this? Was it that BBC article about the experiment performed on mice exposed to varying levels of stress in their youth?

Kevin

Source: http://news.bbc.co.uk/1/hi/sci/tech/8346715.stm

josey_whale

All,

Very interesting paper on the subject published today in Science...

The abstract... "The organized societies of ants include short-lived worker castes displaying specialized behavior and morphology and long-lived queens dedicated to reproduction. We sequenced and compared the genomes of two socially divergent ant species: Camponotus floridanus and Harpegnathos saltator. Both genomes contained high amounts of CpG, despite the presence of DNA methylation, which in non-Hymenoptera correlates with CpG depletion. Comparison of gene expression in different castes identified up-regulation of telomerase and sirtuin deacetylases in longer-lived H. saltator reproductives, caste-specific expression of microRNAs and SMYD histone methyltransferases, and differential regulation of genes implicated in neuronal function and chemical communication. Our findings provide clues on the molecular differences between castes in these two ants and establish a new experimental model to study epigenetics in aging and behavior"

Nature has a report on the paper here

CramCycle

Capt'n Midnight wrote: »

I can't remember offhand but there were effects seen in the grandchildren of Dutch women who starved during pregnancy in 1945.

Suzanne Ozanne from Cambridge gave a talk in UCD 2 years ago and mentioned this study. I don't think it was hers but if I remember correctly both the immediate offspring and the grandchildren were overweight/obese and had a far greater chance of T2DM