Findings published today in the International Journal of Epidemiology suggest that socio-economic status and living standards early in life may actually cause changes in the DNA that is carried in life, regardless of how one's living conditions change along the way. Some adult diseases--type 2 diabetes, coronary heart disease, etc.--have been linked to socio-economic disadvantages in early life, but it is not really well known on why or how.
The study group's sample size is admittedly small, but what they found was significant. In 40 research patients in the UK that are participating in an ongoing study that has documented many aspects of their lives, researchers looked at differences in gene methylation. Methylation is an epigenetic modification to one’s DNA that changes a gene’s activity, generally reducing that activity within the genome. Various factors can influence methylation, including environmental conditions.
In their sample, the researchers looked at DNA taken from the subjects at age 45. They chose subjects that had come from either very high or very low standards of living, and they looked at differences in DNA methylation across some 20,000 genes. They found that 1,252 methylation differences were associated with socio-economic circumstances in early life while just 545 were associated with socio-economic circumstances in adulthood, suggesting that where you come from really does make an impact on the very fiber of your biological being.
Moreover, the methylation patterns were clustered together in large swaths of DNA, suggesting an epigenetic pattern linked to humans’ early environments. If some diseases are linked to a person’s early upbringing, and we can see where there are changes happening in the DNA during early life, then we can narrow the window on where in the genome things like coronary heart disease and diabetes take root. Future research could peg where certain methylation differences are associated with specific diseases, then target those areas with drugs or other treatments.
Source:
http://scienceblog.com/48584/your-dna-may-carry-a-%E2%80%98memory%E2%80%99-of-your-living-conditions-in-childhood/
Are there any methods of manipulating epigenetics at the moment? For instance, are there drugs or pathogens which are capable of demethylating DNA?
ReplyDeleteIncidentally, there was a documentary on epigenetics on SBS last night! It was first discovered by comparing two rare human diseases which are caused by epigenetics and a nucleotide deletion on chromosome 15.
James:
ReplyDeleteThere are methods of directly manipulating epigenetics: dsRNAi. Double-stranded RNA interference stimulates methylation (essentially) in order to silence the gene that gave rise to the double-stranded segment. I'm not sure how you can stimulate demethylation, however.... A pity I missed that documentary, too.
Wayne:
Did the researchers comment on the relative occurence of epigenetic modifications in low and high socio-economic test subjects? Also, technically methylation isn't changing the genetic sequence... :). That's what retroviruses are for! I suppose that it is quite sensible that epigenetic modifications are more common in one's youth, since one would expect to live in a similar situation throughout one's life. Also, perhaps the amounts reflect the additional vulnerability of youth compared with adults? It would be interesting to see if the modifications also affect psychological aspects (e.g. hormone levels, neural pathways, memory formation) as well. Finally, could these epigenetic modifications manifest themselves in differences between adopted children and non-adopted children (and are they reversed during later life, if necessary)?
Josh H