Problem Set 5
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Solutions5

Anthropology 450/550

Problem Set 5


The following data set is a slightly numerically simplified version of a real data set from Mexican-Americans in San Antonio, Texas. This population was scored for their LDL-cholesterol levels and for their genotype at the Apo-E locus. The Apo-E locus codes for apoprotein E, which is a major component of LDL cholesterol.

There are three common alleles at this locus: e2, e3, and e4. The population was found to be in Hardy-Weinberg equilibrium frequencies at this locus with the following allele frequencies: 0.10 for e2, 0.70 for e3, and 0.20 for e4. The mean phenotypes (measured as mg LDL-cholesterol/dL blood plasma) for the various genotypes were as follows:

 

Genotype:                  e2/e2          e2/e3          e2/e4          e3/e3          e3/e4          e4/e4
LDL-Chol.:                  76                 90              115              100              110          106

The average variance of LDL-cholesterol within a genotype was 500.

1. Calculate the genotypic values and genotypic deviations for all genotypes.

2. Calculate the average excesses and average effects for all alleles.

3. Calculate the breeding values and dominance deviations for all genotypes.

4. Calculate the environmental, genetic, total phenotypic, and additive genetic variances. Give the broad-sense and narrow-sense heritiabilities.

5. Increased levels of LDL-cholesterol are associated with increased risk of coronary heart disease. Which genotype is at greatest risk? Which genotype has his/her children at greatest risk?