Question #73500

If the parents are RrFf x RrFf
what is the fraction of the offspring will be tongue rollers and have free earlobes?
What is the fraction of the offspring will be non-rollers and have free earlobes?
What is the fraction of the offspring will be tongue rollers and have attached earlobes?

Expert's answer

As both parents are heterozygous, it is a typical dihybrid cross, which results in the following phenotypic ratio:

9 tongue rollers with free earlobes : 3 non-rollers with free earlobes : 3 tongue rollers with attached earlobes : 1 non-roller with attached earlobes.

Therefore,

what is the fraction of the offspring will be tongue rollers and have free earlobes? Answer 9/16 = 0.5625

What is the fraction of the offspring will be non-rollers and have free earlobes? Answer 3/16 = 0.1875

What is the fraction of the offspring will be tongue rollers and have attached earlobes? Answer 3/16 = 0.1875

9 tongue rollers with free earlobes : 3 non-rollers with free earlobes : 3 tongue rollers with attached earlobes : 1 non-roller with attached earlobes.

Therefore,

what is the fraction of the offspring will be tongue rollers and have free earlobes? Answer 9/16 = 0.5625

What is the fraction of the offspring will be non-rollers and have free earlobes? Answer 3/16 = 0.1875

What is the fraction of the offspring will be tongue rollers and have attached earlobes? Answer 3/16 = 0.1875

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