A fly tier's wet dream

[VERN-O 0]

http://news.bbc.co.uk/2/hi/uk_news/scotlan...ast/8561814.stm

 

Half-cock chicken mystery solved

 

By Huw Williams

BBC Scotland reporter

Researchers say they've solved the mystery of why some chickens hatch out half-male and half-female.

 

About one in every 10,000 chickens is gynandromorphous, to use the technical term.

 

In medieval times, they might have been burned at the stake, as witches' familiars.

 

But now these chickens are shedding important new light on how birds, and perhaps reptiles, develop.

 

It used to be thought that hormones instructed cells to develop in male or female-specific ways.

 

That's what happens in mammals, including humans, and it leads to secondary sexual characteristics like facial hair for men or breasts for women.

 

But scientists at the Roslin Institute and the University of Edinburgh say they have discovered that bird cells don't need to be programmed by hormones.

 

Instead they are inherently male or female, and remain so even if they end up mixed together in the same chicken.

 

It means a half-and-half chicken will have totally different plumage, body shape, and muscle structure on the two halves of its body.

 

It even affects the wattles on the bird's head, and the spurs on its legs. They will be larger on the cockerel half, and smaller on the hen half, of the same bird.

 

Practical uses

 

Dr Michael Clinton of the Roslin Institute led the research, which has just been published in the scientific journal Nature.

 

He said the findings were a surprise.

 

Dr Clinton explained: "We looked at these birds initially expecting them not to be half-male and half-female. We thought there'd be a mutation on one side of the body.

 

"But we found that they were half-male and half-female and that's what actually showed us that the system was different in birds and mammals."

 

And researchers tested their theory with delicate and demanding experiments.

 

"If you put female cells into a male body they'll develop into the normal tissues, but they'll behave as female cells," Dr Clinton said.

 

The hope is that these findings might have immediate practical uses for the poultry industry.

 

Dr Clinton said: "If we can understand what the differences between the male and female identities are, then we can imagine making female birds with the same growth characteristics as males. That would increase productivity, and food security."

 

But if there are vestiges of the same mechanism in mammals, inherited from our reptilian evolutionary ancestors, then the research could help to answer long-standing mysteries of human health.

 

Like, for example, why women live longer than men, or why men are more at risk of heart attacks.

 

"But that will require much more investigation," Dr Clinton insisted.

[Dart 0]

It'd be neat for capes/saddles, but I don't see how the cost would necessarily be less than buying a separate hen/rooster half saddle and cape now.

 

Besides, it kinds creeps me out when scientists talk about "engineering" my food. It sounds like their reasoning to do this wouldn't be for plumage, but to make the hens larger. Or did I miss something?

[neoFLYte 0]

Instead they are inherently male or female, and remain so even if they end up mixed together in the same chicken.

It means a half-and-half chicken will have totally different plumage, body shape, and muscle structure on the two halves of its body.

 

Ehh... it don't work that way. I spent the first 15 years of my adult life doing physiology research. There is a physiological principle among chordates - creatures with a spinal cord, which includes vertebrates (creatures with a vertebral column/backbone) - called bilateral symmetry. The very best you could hope for - although incredibly unlikely - would be a mix of cock feathers and hen feathers on the saddle/cape/etc. on the "half-and-half" chicken. Much more likely, you would find the whole bird covered with "not-quite male" and "not quite female" feather structures. Not to say that the resultant saddle and cape feathers would not be useful... or maybe even fantastic for tying. But the idea of "left side male" and "right side female", or even "front half female" and "back half male" just ain't gonna happen - at least within the known spectrum of genetic expression.

 

[DrVette 0]

Instead they are inherently male or female, and remain so even if they end up mixed together in the same chicken.

It means a half-and-half chicken will have totally different plumage, body shape, and muscle structure on the two halves of its body.

 

Ehh... it don't work that way. I spent the first 15 years of my adult life doing physiology research. There is a physiological principle among chordates - creatures with a spinal cord, which includes vertebrates (creatures with a vertebral column/backbone) - called bilateral symmetry. The very best you could hope for - although incredibly unlikely - would be a mix of cock feathers and hen feathers on the saddle/cape/etc. on the "half-and-half" chicken. Much more likely, you would find the whole bird covered with "not-quite male" and "not quite female" feather structures. Not to say that the resultant saddle and cape feathers would not be useful... or maybe even fantastic for tying. But the idea of "left side male" and "right side female", or even "front half female" and "back half male" just ain't gonna happen - at least within the known spectrum of genetic expression.

I learned some getics and physiology while in school also...I was taught the same thing as you.

Now look closely at the pics and the text...It apears they have stumbled onto a mech. that defies the symetry we learned in comperative phys.. That is more than a little spooky when you think about it. I have to admit that i never played with 10-20K chickens to ever see this. I would realy like to see some comparative genetic tests on that single chicken...it does boggle the noodle.

[JSzymczyk 0]

gynandromorph adult butterflies are VERY highly prized by collectors, and very rare. Some species which have distinct sexual dimorphism (females and males are different colors, for example) look like two creatures were split down the middle and glued together. Very odd, but it happens.