Category Archives: News

The humble fruitfly sheds light on another genetic question


The humble fruitfly sheds light on another genetic question

November 20, 2008

Drosophila pseudoobscura  male

J. T. Patterson, FlyBase

Drosophila pseudoobscura male fly.

It is unknown why females mate with multiple males when mating is frequently costly and a single copulation often provides enough sperm to fertilize all a female’s eggs. One possibility is that remating increases the fitness of offspring, because fertilization success is biased toward the sperm of high-fitness males. We show that female Drosophila pseudoobscura evolved increased remating rates when exposed to the risk of mating with males carrying a deleterious sex ratio–distorting gene that also reduces sperm competitive ability. Because selfish genetic elements that reduce sperm competitive ability are generally associated with low genetic fitness, they may represent a common driver of the evolution of polyandry.

Read more at Science – Selfish Genetic Elements Promote Polyandry in a Fly.

NASA’s Mars Reconnaissance Orbiter Discovers Tucked-in Glaciers


NASA’s Mars Reconnaissance Orbiter Discovers Tucked-in Glaciers

November 20, 2008

Martian Glacier

Image credit: NASA/JPL  

Artist concept of glacier on Mars.

NASA scientists believe they have a solution to how the gently sloping areas that occur at the bases of taller geographical features formed. These aprons consist of blankets of rocky debris protecting massive glaciers of water ice.

John W. Holt of the University of Texas at Austin, who is lead author of the report said, “altogether, these glaciers almost certainly represent the largest reservoir of water ice on Mars that is not in the polar caps. Just one of the features we examined is three times larger than the city of Los Angeles and up to one-half-mile thick. And there are many more. In addition to their scientific value, they could be a source of water to support future exploration of Mars.”

Read more at NASA’s Mars Reconnaissance Orbiter “NASA Space Craft Detects Buried Glaciers on Mars.”