Solving a biological mystery
Harvard scientists have solved the long-standing mystery of how some insects form germ cells, the precursors to the eggs and sperm necessary for sexual reproduction. The answer is shedding light on the evolutionary origins of a gene that has been long viewed as critical to the process. As described in a paper published Dec. 4 in Current Biology, a team of researchers led by Cassandra Extavour, associate professor of organismic and evolutionary biology, discovered that a cricket, a so-called lower insect, possesses a variation of a gene — called oskar — that has been shown to be critical to the production of germ cells in “higher” insects, particularly fruit flies. That discovery, Extavour said, suggests that the oskar gene emerged far earlier in insect evolution than researchers previously believed. “The prevailing hypothesis was that, since only higher insects appeared to possess the oskar gene, that it must have emerged after the two...