A whimsical attempt to establish a herd of mouflon for sport hunting on a remote island in the Indian Ocean 50 years ago has inadvertently created a laboratory for genetic researchers and led to a surprising discovery.

"Regressive evolution," or the reduction of traits over time, is the result of either natural selection or genetic drift, according to a study on cavefish by researchers at New York University's Department of Biology, the University of California at Berkeley's Department of Integrative Biology, and the Harvard Medical School.

Some breaking news, just in time for Valentine's Day: Researchers have identified something called "sperm competition" that they think has evolved to ensure a genetic future. In sexual reproduction, natural selection is generally thought of as something that happens prior to - and in fact leads to -- the Big Event.

Darwin explained how beneficial traits accumulate in natural populations, but how do costly traits evolve? In the past, two theories have addressed this problem. The theory of hitchhiking suggests that genes that confer a cost to their bearer can become common in natural populations when they "hitch a ride" with fitter genes that are being favored by natural selection.