06. December 2020
Biological age is a measure of lifestyle, habits, and innate factors that cause us to age. How an individual’s biological age should be measured and what factors should be included and weighted to calculate a biological age continues to be of great interest to researchers. Today, it is understood that individuals experience different rates of aging resulting from progressive deterioration, occurring simultaneously at the molecular, cellular, tissue, organ, and functional levels. This is...
06. December 2020
Tobacco use remains one of the most important risk factors for developing serious conditions such as heart disease, lung disease, and cancer. Due to its influence on health, underwriting places significant value on identifying tobacco exposure among life insurance applicants. Accordingly, the life insurance industry widely screens for tobacco use by testing with the biomarker cotinine, a metabolite of nicotine, in an applicant’s clinical chemistry panel. The challenge with measuring cotinine...
03. December 2020
As we have seen from the roundworm example, epigenetic effects (in this case extended lifespan) can sometimes be passed from one generation to the next, although the effects only seem to last for a few generations. Are there examples where epigenetic effects carry over to subsequent generations in humans or other mammals? There is some evidence that the effects of the Dutch Hunger Winter affected grandchildren of women who were pregnant during the famine. Similarly, in a study of a 19th century...
03. December 2020
Angelmann and Prader-Willi syndromes are two distinct genetic conditions with different symptoms, both caused by loss of a part of chromosome 15. Children who inherit one copy of this faulty chromosome develop either Angelmann or Prader-Willi syndrome, despite having a normal copy of the chromosome from their other parent. So how does the same mutation (loss of part of chromosome 15) lead to these two different conditions? The answer lies in the discovery that this particular piece of...
03. December 2020
Whereas the term “genome” refers to the entire DNA sequence of an organism (three billion letters of it for humans), the epigenome refers to the entire pattern of epigenetic modifications across all genes, including methyl DNA tags, methyl histone tags, acetyl histone tags and other chemical tags that we have not mentioned, in each cell type of an organism. This represents an almost unimaginable amount of information, dwarfing even the human genome project. Nevertheless, knowledge of the...
03. December 2020
So far we have described some specific cases of epigenetic regulation, but we now know that epigenetics in its broad sense, (how genes are expressed and used, rather than the DNA sequence of the genes themselves) is central to how a fertilised egg can eventually give rise to a whole organism and how cells of, let’s say your skin, remain skin cells and are different from your brain cells, despite containing exactly the same genes. Shortly after fertilisation, a developing human embryo consists...