Tag Archives: Methylation

Epigenetic study confirms: Tobacco addiction during pregnancy

Courtesy of FreeDigitalPhotos.netIn the morning paper I found a very interesting article from Kathrin Zinkant about smoking during pregnancy (Sueddeutsche Zeitung, Wissen, July 31 2014). It is long known that smoking during pregnancy is taboo. However, estimated 5% – 10% of pregnant women in Germany still smoke, many of them because they are not aware of the pregnancy in the first trimester. Tobacco toxins can harm significantly. Known consequences are reduced weight at birth, damaged lung function and unusual behavior.

In the world’s largest study of the consequences of smoking during the first trimester of pregnancy the DNA methylation status of almost 900 new born babies was studied and compared with the DNA methylation of babies whose mothers did not smoke. It could clearly be shown that the methylation status between the two groups differed. Methylation can alter the activity of genes up to complete silencing. There is evidence that such methylation patterns can be inherited to later generations.

Affected genes belong to known developmental genes and also genes that are involved in tobacco addiction. This confirms the suspicion that tobacco addiction may already be induced during pregnancy. Despite the fact that women should quit smoking before they become pregnant (or better do not smoke at all) it has also to be considered that second-hand smoking is a permanent danger for unborn, child and adult health.

Epigenetic Studies by direct Single-Molecule Sequencing?

Next generation sequencing allows researchers to generate high resolution maps of epigenetic modifications for whole genomes (epigenome). Whole genome methylation pattern has been determined e.g. for A. thaliana by sequencing bisulfite treated DNA with Illumina technology (Lister et al., 2008 and Cokus et al., 2008).

In the near future epigenetic studies may be possible without bisulfite treatment by single-molecule real-time sequencing (SMRT). The first proof of concept study promises direct detection of modified nucleotides as well as discrimination between different types of modifications (Flusberg et al., 2010).