|MadSci Network: Genetics|
If cows would produce chocolate milk, how could we make some decent cheese?
I don't think people would like chocolate cheese (at least not in Europe ;). Also calves may not like to drink chocolate milk from their mothers.
Back to your question. If one makes chololate milk, one takes normal milk to start with. The 'white' stuff in the milk is among others proteins and fats. They are required for the 'taste' of milk AND chocolate milk. So you should keep the genes for these proteins.
On the cocoa side, there is not one gene involved in making the chocolate experience. To make things more complicated, cocoa-beans are treated for a long time to give the right taste.
In summary, making chocolate milk directly with cows is almost impossible. And, in my opinion more important, it isn't ethical to do so. Chocolate milk can be readily produced by mixing cocoa-powder, milk and sugar. There is no need to genetically modify cows.
However, it is possible to produce certain drugs in cows. A dutch company called Genepharming has made cows that produce a drug (to prevent sickness in babies) in their milk. This drug can easily be collected (just milk the cow) and the solution it is in (milk) is not dangerous (it's even healthy).
Rolf 'Got Milk?' Marteijn
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