Genetics 311, Practice problem set #6.

1) A representative sample of lamb weaning weights is shown below, expressed in pounds.  Determine the weight limits within which 95% of all lambs from this population are expected to wean.   81,   81,   83,   101,   86,   65,   68,   77,   66,   92,   94,   85,   105,   60,   90.

Answer: 55.7 lb. > wt > 108.9 lb.

2) Consider the following data on yield in inbred lines of tomatoes (bushels per acre):
Line Mean Std. Dev.
R26 293 51
R93 147 48
R26xR93 hybrid 206 53

The R26 x R93 hybrids were randomly crossbred to produce an F2 generation.  The F2 yielded
253 bushels of tomatoes per acre, with a standard deviation of 97.  What is the broad-sense
heritability of this trait?

Answer: H2 = 72.7%

3) One of the major genes encoding coat color in domestic cats is X-linked.  CBCB and CBY cats are black, COCO and COY cats are orange, and CBCO cats are "tortoise-shell."   A survey of Nashville cats found 218 black male, 151 black female, 37 orange male, 6 orange female, and 93 tortoise-shell females.  What is the frequency of the CB gene?

Answer: 0.811

4) Attached ear lobes and widow's peak are two independently assorting human traits apparently encoded by recessive alleles.  A sample of 100 people yielded the following: 6 with both traits, 24 with attached lobes only, and 13 with widow's peak only.  Assuming Hardy-Weinberg
equilibrium, what are the frequencies of the attached and widow's peak genes?

widow's peak = 0.436
attached = 0.548

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