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Epigenetics: A Turning Point in Our Understanding of Heredity
from Scientific American
In a study published in late 2011 in Nature, Stanford University geneticist Anne Brunet and colleagues described a series of experiments that caused nematodes raised under the same environmental conditions to experience dramatically different lifespans. Some individuals were exceptionally long-lived, and their descendants, through three generations, also enjoyed long lives. Clearly, the longevity advantage was inherited. And yet, the worms, both short- and long-lived, were genetically identical.
This type of finding--an inherited difference that cannot be explained by variations in genes themselves--has become increasingly common, in part because scientists now know that genes are not the only authors of inheritance. There are ghostwriters, too. At first glance, these scribes seem quite ordinary--methyl, acetyl and phosphoryl groups, clinging to proteins associated with DNA, or sometimes even to DNA itself, looking like freeloaders at best.
Their form is far from the elegant tendrils of DNA that make up genes, and they are fleeting, in a sense, erasable, very unlike genes, which have been passed down through generations for millions of years. But they do lurk, and silently, they exert their power, modifying DNA and controlling genes, influencing the chaos of nucleic and amino acids. And it is for this reason that many scientists consider the discovery of these entities in the late 20th century as a turning point in our understanding of heredity, as possibly one of the greatest revolutions in modern biology--the rise of epigenetics.
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