1. Three pairs of genes with two alleles each (A1 and A2, B1 andB2, and C1 and C2) influence lifespan in a human population. Thealleles of these genes have an additive relationship and add thenumber of years indicated to the lifespan of the individual.
| allele | years |
| A1 | 15 |
| A2 | 4 |
| B1 | 16 |
| B2 | 8 |
| C1 | 13 |
| C2 | 9 |
a. If lifespan were entirely genetically determined, what is theminimum possible lifespan and the associated genotype?
b. If lifespan were entirely genetically determined, what is themaximum possible lifespan and the associated genotype.
c. The following is a range of ages from individuals in thispopulation. If the genetic variance is 25.7, measure thebroad-sense heritability of lifespan
| lifespan |
| 65 |
| 77 |
| 89 |
| 76 |
| 99 |
| 97 |
| 87 |
| 81 |
| 78 |
| 91 |
d. Explain what this heritability means, and why the measure maybe so low.
