how do i explain the ratio of mendelian traits in humans in my class? traits such as dimple cheek/no dimple?

Question

in a zoology practical class, we were asked to check ourselves for ten traits and write down the gene symbols. the traits were in pairs such as widow's peak/no widow's peak, tongue rollers/non-tongue rollers, chin fissure/no chin fissure e.t.c. we were asked to pool the results for both sides and find the ratios for my department after which we were asked to reach certain conclusions for the results and explain the results.

Answer 1

Some of these traits you looked at were recessive or not phenotypic unless homozygous. For the recessive trait to be expressed as the phenotype both parents must donate a recessive allele.
Ratios of expression in the offspring vary depending on the genotype of the parents. If the parents were both heterozygous this is a hybrid cross that will have the genotype of 1:2:1 & phenotype of 3:1. If one parent is homozygous while the other is heterozygous the cross will be 1:1. To complete this properly the parents need to be asked to contribute the details of their traits also.

The other way of looking at trait is its prevalence in the entire population. This can be compared with the incidence of expression in your class. If it occurs in 1% of the population and it is matched by 1% of the class showing the trait then the class shows a normal population distribution.

Part of class with trait : without trait