Among Native Americans two types of earwax cerumen are seen

Among Native Americans, two types of earwax (cerumen) are seen, dry and sticky. A geneticist studied the inheritance of this trait by observing the types of offspring produced by different kinds of matings and obtained the following data: Assuming the earwax phenotype is determined by a single locus, which allele is dominant (sticky or dry)? Why are there no 3:1 or 1:1 ratios in the data shown in the chart?

Solution

A.. Assuming the earwax phenotype is determined by a single locus,the allele which is dominant is STICKY.

B. There are no 3:1 or 1:1 ratios in the data shown in the chart because this is due to pattern of inheritance.