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...without dramatic changes in warmth and brightness that might have prevented the emergence and evolution of life - and Kepler now reports that two-thirds of the sunlike stars it's monitoring are no more active than the sun at its most turbulent. Lots of stable suns could mean at least a handful of promising Earths - and those, in turn, could mean living company for our own still lonely world...
...many other scientists working separately over the past 20 years - have given birth to a new science called epigenetics. At its most basic, epigenetics is the study of changes in gene activity that do not involve alterations to the genetic code but still get passed down to at least one successive generation. These patterns of gene expression are governed by the cellular material - the epigenome - that sits on top of the genome, just outside it (hence the prefix epi-, which means above). It is these epigenetic "marks" that tell your genes to switch on or off, to speak loudly...
Since 2004, the FDA has approved three other epigenetic drugs that are thought to work at least in part by stimulating tumor-suppressor genes that disease has silenced. The great hope for ongoing epigenetic research is that with the flick of a biochemical switch, we could tell genes that play a role in many diseases - including cancer, schizophrenia, autism, Alzheimer's, diabetes and many others - to lie dormant. We could, at long last, have a trump card to play against Darwin...
...funny thing is, scientists have known about epigenetic marks since at least the 1970s. But until the late '90s, epigenetic phenomena were regarded as a sideshow to the main event, DNA. To be sure, epigenetic marks were always understood to be important: after all, a cell in your brain and a cell in your kidney contain the exact same DNA, and scientists have long known that nascent cells can differentiate only when crucial epigenetic processes turn on or turn off the right genes in utero...
...Make a Better Mouse As momentous as epigenetics sounds, the chemistry of at least one of its mechanisms is fairly simple. Darwin taught us that it takes many generations for a genome to evolve, but researchers have found that it takes only the addition of a methyl group to change an epigenome. A methyl group is a basic unit in organic chemistry: one carbon atom attached to three hydrogen atoms. When a methyl group attaches to a specific spot on a gene - a process called DNA methylation - it can change the gene's expression, turning it off or on, dampening...