Hermaphrochickens

Chickens don’t follow the mammalian model in the way that gender is assigned to them before birth according to discoveries by scientists at the University of Edinburgh.

"Chicken sex doesn’t work like ours. No, not that sex — but the process by which an embryo becomes a recognizably male or female animal. Unlike mammals, it’s not hormones that dictate a chicken’s sex. It’s a fundamental property of the cells themselves. But this only became apparent when biologists investigated several odd chickens that were half male and half female, as if a line were drawn down the center of their bodies. ‘We assumed this was caused by one side of the body having some kind of sex chromosome anomaly,’ said Michael Clinton, a University of Edinburgh developmental biologist and co-author of the study, described March 10 in Nature. ‘But when we looked at them closely, they were composed of entirely normal cells. We realized that birds don’t follow the mammalian model.’ In mammals, there are two types of sex-determining chromosomes, X and Y. Each cell in an embryo has a pair of chromosomes, either XX or XY, but the cells are otherwise identical. Then, early in development, in response to some environmental cue, a group of cells that will someday become ovaries or testes start to produce hormones that cause other cells to develop in male- or female-specific ways. It’s the hormones that matter: Exposed to lots of testosterone and deprived of estrogen, cells with female chromosomes will form masculine tissues, and vice versa."

LinkedIn meets Tinder in this mindful networking app

Swipe right to make the connections that could change your career.

Getty Images
Sponsored
Swipe right. Match. Meet over coffee or set up a call.

No, we aren't talking about Tinder. Introducing Shapr, a free app that helps people with synergistic professional goals and skill sets easily meet and collaborate.

Keep reading Show less

Think you’re bad at math? You may suffer from ‘math trauma’

Even some teachers suffer from anxiety about math.

Image credit: Getty Images
Mind & Brain

I teach people how to teach math, and I've been working in this field for 30 years. Across those decades, I've met many people who suffer from varying degrees of math trauma – a form of debilitating mental shutdown when it comes to doing mathematics.

Keep reading Show less

A world map of Virgin Mary apparitions

She met mere mortals with and without the Vatican's approval.

Strange Maps
  • For centuries, the Virgin Mary has appeared to the faithful, requesting devotion and promising comfort.
  • These maps show the geography of Marian apparitions – the handful approved by the Vatican, and many others.
  • Historically, Europe is where most apparitions have been reported, but the U.S. is pretty fertile ground too.
Keep reading Show less

How KGB founder Iron Felix justified terror and mass executions

The legacy of Felix Dzerzhinsky, who led Soviet secret police in the "Red Terror," still confounds Russia.

Getty Images
Politics & Current Affairs
  • Felix Dzerzhinsky led the Cheka, Soviet Union's first secret police.
  • The Cheka was infamous for executing thousands during the Red Terror of 1918.
  • The Cheka later became the KGB, the spy organization where Russia's President Putin served for years.
Keep reading Show less