A poultry farmer hopes to profit from the current craze for keeping egg laying chickens as pets and wishes to increase his stock of interesting and unusual breeds. (a) The farmer crossed a pure-breeding white chicken with a pure-breeding black chicken and found that 100% of their offspring (the F1 generation) were an attractive blue colour. Hoping to get more of these blue chickens he crossed several of the F1 offspring, but found that he had the following numbers of chickens in the F2 generation: Black, 28 White, 30 Blue, 60. Assign symbols to the alleles controlling these colour characters and draw genetic cross diagrams illustrating both crosses . Explain why the mode of inheritance of feather colour in this case means that the farmer will never be able to develop pure-breeding blue chickens.
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