Exercising one leg for a few months led to changes in over 5,000 sites on the genome of muscle cells in the exercised leg and none in the unexercised one. ah methylation A NY Times piece offers more detail.
But the changes within the muscle cells’ DNA were more intriguing. Using sophisticated genomic analysis, the researchers determined that more than 5,000 sites on the genome of muscle cells from the exercised leg now featured new methylation patterns. Some showed more methyl groups; some fewer. But the changes were significant and not found in the unexercised leg.
Interestingly, many of the methylation changes were on portions of the genome known as enhancers that can amplify the expression of proteins by genes. And gene expression was noticeably increased or changed in thousands of the muscle-cell genes that the researchers studied.
Most of the genes in question are known to play a role in energy metabolism, insulin response and inflammation within muscles. In other words, they affect how healthy and fit our muscles — and bodies — become.
They were not changed in the unexercised leg.
The upshot is that scientists now better understand one more step in the complicated, multifaceted processes that make exercise so good for us.