Solutions to Quantitative Genetics Practice Problems

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  1. If the slope of a parent-offspring regression is 0.25, what is the heritability h2?

  2. If the slope of a midparent-offspring regression is 0.75, what is the heritability h2?

  3. If h2 = 0.3, the population mean is 10, and the value of a parent is 15, what is the expected mean of an offspring from this parent?

  4. If h2 = 0.4, the population mean is 16, and the value of both parents are mother = 12, father = 17.

    What is the midparental value?

    What is the expected mean of an offspring from these parents?

  5. If the mean of a group of selected parents is 10 units above the population mean, while the mean value of their offspring is 3 units above the original population mean, what is the heritability h2?

  6. Suppose 5 locus underlie a character of interest and that each capital letter allele at each locus adds value one to the character (so that genotype aabbccddee has value 0 while AABBCCDDEE has value 10). Suppose Freq(A) = Freq(B) = ... = Freq(E) and we assume H-W.

    If Freq(A) = 0.7, what is the probability of an individual with genotype aabbccddee ?

    Suppose now that selection changes the allele frequencies to Freq(A) = 0.1, now what is the probability of an individual with genotype aabbccddee ?

  7. If the correlation between dizygotic twins for weight is 0.5, while the correlation between monozygotic twins is 0.75, what is the heritability of weight?