"Achondroplasia is a form of dwarfism that is inherited in humans as an autosomal dominant disorder. A survey in a small country showed that, within a two-year period, there were 12 children with normal parents born with this disorder out of a total of 420,000 births. What is the mutation rate in mutations/locus/generation

The mutation rate in mutations/locus/generation equals 0.000014 or 1.4 x 10⁻⁵

Explanation:

From a total of 420.000 births, only 12 of these children born with this disorder, so:

420.000 total of newborns 100%

12 dwarf newborns X = 0.0028%

But this percentage corresponds to a period of two years. In one year, or one generation, the percentage would be:

2 years 0.0028%

1 year X= (1 x 0.0028)/2 =  0.0014%  

Which means that the mutation rate in mutations/locus/generation equals 0.000014 or 1.4 x 10⁻⁵

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