Perhaps an explanation is in order. Nicholas Wade writes in the NY Times that germ cells (egg and sperm) are, so to speak, immortal. "A little piece of the germline’s immortality, it now seems, can be acquired by the ordinary cells of the body, and used to give the organism extra longevity."
Researchers know that manipulating the insulin-signaling pathway can affect lifespan, similar to the way exercise and a low fat diet can. They also know that genomic instability in somatic (non-germline) cells "increases with age, and this decline in somatic maintenance might be regulated to facilitate resource reallocation towards reproduction at the expense of cellular senescence," the authors write in the Nature article.
So, the researchers looked at C. elegans mutants and noticed that the "somatic tissues of insulin-like mutants are more germline-like and protected from genotoxic stress." In the experiment, the master regulator gene - daf-16 in C. elegans, FOXO in mammals - can switch on two genes in the somatic cells that are usually active only in the germline cells and are kept permanently switched off in the somatic cells.
And sadly, every time I see "fox" in a word, I immediately think of this.