Its head looks like a turkey, its body resembles a chicken – now scientists can explain why one of the poultry（家禽） world's most curious specimens has developed such a distinctive look in next week's issue of the online, open access journal PLoS Biology. The Transylvanian naked neck chicken – once dubbed a Churkey or a Turken because of its hybrid（混合的，杂种的） appearance – has developed its defining feature because of a complex genetic mutation. Transylvanian naked necks, which are thought to have originated from the north of Romania, have been around for hundreds of years and were introduced to Britain in the 1920s. Researchers at The Roslin Institute at The University of Edinburgh analysed DNA samples from naked neck chickens in Mexico, France and Hungary, and they found that a vitamin A-derived substance produced around the bird's neck sensitised the neck skin to the effects of the genetic mutation. The mutation causes enhanced production bodywide of an inhibitory（禁止的） protein called BMP12 and the combination of these two signals caused the bird to have an outstanding bald（秃顶的） neck. Skin samples from embryonic chickens were also analysed using complex mathematical modelling to identify the effects of these signals on feather patterning. The discovery has implications for understanding how birds – including vultures（秃鹰） – evolved to have featherless necks due to their metabolism of vitamin A selectively in neck skin.

Dr. Denis Headon, who led the research at The Roslin Institute, said: "Not only does this help our understanding of developmental biology and give insight into how different breeds have evolved but it could have practical implications for helping poultry production in hot countries including those in the developing world." Chickens with naked necks are much better equipped to withstand the heat.