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."
No, the Syrian civil war is not over. But it might be soon. Time for a recap
- The War in Syria has dropped off the radar, but it's not over (yet)
- This 1-minute video shows how the fronts have moved – and stabilised – over the past 22 months
- Watching this video may leave you both better informed, and slightly queasy: does war need a generic rock soundtrack?
Sarco assisted suicide pods come in three different styles, and allow you to die quickly and painlessly. They're even quite beautiful to look at.
Death: it happens to everyone (except, apparently, Keanu Reeves). But while the impoverished and lower-class people of the world die in the same ol' ways—cancer, heart disease, and so forth—the upper classes can choose hip and cool new ways to die. Now, there's an assisted-suicide pod so chic and so stylin' that peeps (young people still say peeps, right?) are calling it the "Tesla" of death... it's called... the Sarco!
Entrepreneur and author Andrew Horn shares his rules for becoming an assured conversationalist.
- To avoid basing action on external validation, you need to find your "authentic voice" and use it.
- Finding your voice requires asking the right questions of yourself.
- There are 3-5 questions that you would generally want to ask people you are talking to.
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