Dear SP,

human LINE-1 polymorphisms present in the population are well known by now, see for example Ewing (2011) [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3106331/]

Somatic transpositions have also been observed, for example in cancer cells [http://www.ncbi.nlm.nih.gov/pubmed/22745252], but more interestingly, in the human brain [http://www.ncbi.nlm.nih.gov/pubmed/23101622].

As for genomic stability, I believe it is a "chicken and egg" problem right now, at lease as far as cancer development is involved. Opinions there differ. The elements are, however, considered as drivers of evolutionary change [see e.g.: http://www.ncbi.nlm.nih.gov/pubmed/23101622 ; http://www.ncbi.nlm.nih.gov/pubmed/15969349 ; http://www.ncbi.nlm.nih.gov/pubmed/12176313]

Dear SP,

human LINE-1 polymorphisms present in the population are well known by now, see for example Ewing (2011) [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3106331/]

Somatic transpositions have also been observed, for example in cancer cells [http://www.ncbi.nlm.nih.gov/pubmed/22745252], but more interestingly, in the human brain [http://www.ncbi.nlm.nih.gov/pubmed/23101622].

As for genomic stability, I believe it is a "chicken and egg" problem right now, at lease as far as cancer development is involved. Opinions there differ. The elements are, however, considered as drivers of evolutionary change [see e.g.: http://www.ncbi.nlm.nih.gov/pubmed/23101622 ; http://www.ncbi.nlm.nih.gov/pubmed/15969349 ; http://www.ncbi.nlm.nih.gov/pubmed/12176313]

I agree on whote ML wrote. Transposon activity does not present a significant threat to genome stability provided that epigenetic regulators are working normally. However, epigenetic systems might be compromised, e.g. under stress conditions. For example, insufficient DNA methylation may release trancription block of silent transposons that may eventuelly intergate into novel chromosomal positions, and hence destabilise the genome. These reintegration events are, however, rare and may be limited to highly plastic genomes, such as the plants.

Dear ML,

Thank you for the article links regarding the novel activity of L1. I was going through this theme as a hypothesis that may lead to toxic results. In accordance to what AK has mention in the subsequent comment, that is exactly what I am trying to prove with my field of interest. I am working on epigenetic deregulation by toxic stress in humans, specially with arsenic. I am asking AM, if there can be any relevant article that pose danger to the integrity of the genome upon epigenetic deregulation? If so, then the links would be very useful.

Thanks to all for this guidance.

Somnath.

Dear Somnath,

There is relatively abundant literature on epigenetic responses to stress factors. Below, please find some links and PDF attached.

Your project seems to be interesting. Just let me a small technical note. You may need to distinguish the genome damage induced by action of transposon elements from the genome damage caused by apoptotic processes/nucleosomal fragmentation of DNA/. Apoptosis is often triggered in cells exposed to heavy metals (see Fojtova et al, attached)

http://www.ncbi.nlm.nih.gov/pubmed/22740325

http://www.ncbi.nlm.nih.gov/pubmed/24752783

http://www.ncbi.nlm.nih.gov/pubmed/24497839

http://www.ncbi.nlm.nih.gov/pubmed/24254230

http://www.ncbi.nlm.nih.gov/pubmed/23528182

http://www.ncbi.nlm.nih.gov/pubmed/20090938

http://www.ncbi.nlm.nih.gov/pubmed/20040583

Best,

Ales

Dear Ales, 

Thank you for the links and the attachments.

Thank you all.

I would like to thank you all for your valuable discussion and would like to share with you my latest publication in this topic 

Article Environmental Stress Activation of Plant LTR-Retrotransposons

 I also think that this article is very important and useful in this topic. I hope this helps.  Good luck

Article Epigenetic activation of genomic retrotransposons