2017/06/13

Environmental genomic memories can be passed on for 14 generations

Over 100,000,000 histone modifications maintain stable epigenetic inheritance

Excerpt: "In multicellular organisms, specificity of cell types is maintained by mitotically heritable differences in gene expression, which are in part regulated by epigenetic mechanisms. These include RNA-based mechanisms, histone modifications, and DNA methylation. The full range of epigenetic marks is currently unknown but is potentially enormous, considering that the diploid human epigenome contains >108 Cytosines (of which >107 are CpGs) and >108 histone tails that can all potentially vary.

DNA methylation is one of the best understood epigenetic modification and has an important role in several biological processes such as genome imprinting, defence against viral sequences, inhibition of recombination, as well as assembly of heterochromatin.

Aberrant DNA methylation patterns have been linked to genomic instability and increased mutation rates. The role of DNA methylation has been mainly explored in the context of cancer. Findings from these studies have extensively demonstrated that cancer development is associated with gain of DNA methylation at CpG islands, loss-of-imprinting and epigenetic remodeling of repeat elements. Interestingly, altered DNA methylation seems to be involved in the pathogenesis of other age-related diseases, such as cardiovascular, neurological and metabolic disorders, and autoimmune diseases."

My comment: 108 histone tails, a biological bar-coding mechanism, can all potentially vary with several other epigenetic mechanisms in our cells. They all are affected by foods, stress, climate and other environmental factors. This is why we can only observe variation within created kinds but no evolution from a bacterium into something other form of life.

Aberrant methylation patterns have been linked to genomic instability and increased mutation rates. This means that poor nutrition, alcohol consumption, smoking, toxins etc. expose us to genetic errors. Genetic mutations never result in adaptation or evolution. There are no mechanisms for large scale evolution. That's why creation and design. Don't get misled.

https://www.sciencedaily.com/releases/2017/04/170420141753.htm