‘Junk?’ Not so fast
Ever since the Human Genome Project decoded the genome, the prevailing scientific view has been that only the 2 percent that makes proteins — the building blocks of cells — was important. The rest was deemed not functional, or “junk.” But from his days in graduate school, through his postdoctoral fellowship, and now as a Harvard Stem Cell scientist, John Rinn has been digging through the genome, challenging that prevailing belief. Now, Rinn and his Harvard Stem Cell Institute colleagues, including neurobiologist Paola Arlotta, have carried out an elegant and important experiment in which they have demonstrated that much of what had been dismissed in fact plays as vital a role as protein-coding genes. Rinn and his colleagues have generated 18 strains of mutant mice, removing from each a different piece of “junk” genome, or so-called long intergenic noncoding RNAs (lincRNAs). If the lincRNA truly had been “junk,” nothing should have happened. What...