You are studying a disorder that is based on the genetic composition at three loci. Assume that a dominant allele at any locus a
dds 6 units of risk for the disorder and that a recessive allele at any locus adds 2 units of risk for the disorder. Individuals with 29 or more units of risk develop the disorder. The environment does not affect the presence or absence of this disorder. How many risk units will be present in an individual of genotype AABbCc?
This disorder follows quantitative inheritance. It is controlled by three genes which do not show the usual dominant-recessive relationship . The six alleles individually contribute to the effect which add up to produce the cumulative phenotype. Dominant allele contributes 6 units of risk whereas recessive allele contributes 2 units of risk.
Individual with genotype AABbCc has four dominant alleles (AABC) and two recessive alleles (bc). So their total risk units =
