With regard to the ABO blood types in humans, determine the genotype of the male parent and female parent shown here: Male parent: Blood type B; mother type O Female parent: Blood type A; father type B Predict the blood types of the offspring that this couple may have and the expected proportion of each.

Key Concepts

ABO Blood Group System

The ABO blood group system classifies human blood into four main types: A, B, AB, and O, based on the presence or absence of antigens on the surface of red blood cells. Blood type A has A antigens, type B has B antigens, type AB has both, and type O has neither. The inheritance of these blood types is determined by two alleles, where A and B are co-dominant, and O is recessive.

Genotype and Phenotype

Genotype refers to the genetic makeup of an individual, specifically the alleles inherited from parents, while phenotype is the observable expression of those genes, such as blood type. For example, a person with genotype AO will have phenotype A blood type. Understanding the relationship between genotype and phenotype is crucial for predicting the blood types of offspring based on parental genotypes.

Punnett Square

A Punnett square is a diagram used to predict the genetic outcomes of a cross between two individuals. It allows for the visualization of how alleles from each parent combine to form potential genotypes of offspring. By filling in the Punnett square with the possible gametes from each parent, one can determine the expected proportions of each blood type in the offspring.