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Video transcript: The development game

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July 2011

Dr Denis Headon, Group Leader, The Roslin Institute
My group studies skin development particular the growth of feathers and hairs and recently we were looking in particular at a chicken for study. Further development and sheep are studying hair development. Now these features, hairs and feathers, are important production traits.

Video shows wooly sheep in a herd

For example, sheep have been bred for many centuries to produce wool, to retain the hair fibre so that they produce so that people can use those fibres to make clothes. More recently, synthetic fibres have been started to depress the wool price and, at the moment, it is more economical for farmers to have sheep that shed their wool rather than to shear the sheep and sell the fleece on.

Video shows black and white photographs of the old days of sheep sheering by hand

So, for many centuries of course, Britain's wealth has been built on the wool industry but this interest in essentially getting rid of wool or having it shed in the fields so that it ends up in birds nests has become more pressing and so we are interested in understanding how tropical sheep shed their wool and asking whether we could introduce those genes into British sheep.

From studies done by some farmers so far it seems that this shedding of the wool is not a particular problem.

Video shows a field of sheep, with varying thicknesses of fleece

During winter for example the animals are perfectly capable to surviving happily even on Scottish hillsides with these shedding genes. So we are interested in understanding how this wool shedding works and perhaps this is something that will also tell us about how animals in general regulate the length of their hair. That basic biology connection with agriculture is something that we are particularly interested in bringing out so finding traits that are important for production and then also asking how they tell us about the development of tissues and organs in all species.

Video shows a scientist holding up a very young chicken

We studied further development in chicken particularly in embryos where the feather pattern is initially laid down. What we see in broiler chickens particularly is that they have been selected for very rapid growth over the past 50 years so these birds eat very rapidly, they put on weight very quickly and this is something that is very good for the consumer because it's a useful production trait. Associated with this is that the animals undergo heat stress particularly in hot countries in summer time and there are some chicken breeds that have reduced feathering as a natural consequence of mutations that they carry and...

Video shows a group of specially adapted broiler meat chickens

...it has been shown that these birds with reduced feather undergo less heat stress in particularly hot countries and this seems to be a particular useful trait to introduce to broiler meat chicken so they undergo less heat stress, they put on weight more rapidly and so they produce more and also slightly less feather waste is produced and so this is something that is more economically beneficial.

So we are understanding the genetic basis of this reduced feathering in chickens, partly to aid in production and welfare and partly also to understand the basic biology of tissue organisation during development.

Video shows a close-ups of chicken, duck and mouse skin

We find that it is possible to culture embryonic chicken skin in vitro so this is something that allows us to do experiments in developing embryonic tissues without examining animals directly and what we find is that we are able to understand the process of feather production quite accurately but a couple of days of examining these cultured skins we find that the cells communicate with one another to decide essentially where a feather should go and using computational simulations and some molecular biology techniques we are able to understand the type of communication that these cells use and how that's altered to produce reduced feathering in some chicken breeds.

ENDS