Month: April 2020

Enlarge / A red-eared slider. (credit: Greg Hume/Wikimedia Commons)

There's a global pandemic happening on a scale that hasn't been seen in roughly a century. So we decided it would be the perfect time to talk about turtle sex. Not turtles having sex, which is undoubtedly an interesting geometry problem, but rather the process by which turtles develop as male or female.

That process is interesting because it seems, at least from our XY chromosomal perspective, to be a bit haphazard: turtles and many other reptiles determine their sex based on ambient temperature. In elevated temperatures, most of the eggs will develop as female; at lower temperatures, most of the eggs will develop as males. We don't really know how they register the temperature and somehow translate it to a complex program of anatomical development. But a new paper in Science fills in some of our gaps.

Sex, of the less interesting sort

If pressed, most of us could remember that human sex determination involves the X and Y chromosomes. But it's often overlooked how things get very complicated downstream of this simple signal. A gene on the Y chromosome turns out to be critical to registering which chromosome combination someone has. A specific tissue interprets the presence or absence of that gene to start a cascade of hormones that reshape how tissues develop and continue to influence things throughout a person's life.

Enlarge / View of IS-901 satellite from Mission Extension Vehicle-1’s “near hold” position. (credit: Northrop Grumman)

In a triumph for the nascent industry of "satellite servicing," an aging communications satellite has returned to service in geostationary orbit.

Northrop Grumman announced Friday that its Mission Extension Vehicle-1, or MEV-1, has restored the Intelsat 901 satellite and relocated it into a position to resume operations.

"We see increased demand for our connectivity services around the world, and preserving our customers’ experience using innovative technology such as MEV-1 is helping us meet that need,” Intelsat Chief Services Officer Mike DeMarco said in a news release.