The ABO and MN blood groups are shown for four sets of parents (1 to 4) and four children (a to d). Recall that the ABO blood group has three alleles: I^A, I^B and i. The MN blood group has two codominant alleles, M and N. Using your knowledge of these genetic systems, match each child with every set of parents who might have conceived the child, and exclude any parental set that could not have conceived the child.

Verified step by step guidance

1. Understand the genetic systems involved: The ABO blood group system has three alleles (I^A, I^B, and i), where I^A and I^B are codominant, and i is recessive. The MN blood group system has two codominant alleles, M and N, meaning both alleles are expressed if present.
2. Determine the possible genotypes for each parent in the ABO system. For example, a parent with blood type A could have the genotype I^A/I^A or I^A/i, while a parent with blood type O must have the genotype i/i. Similarly, analyze the MN blood group system, where a parent with blood type M could have the genotype M/M, and a parent with blood type MN must have the genotype M/N.
3. For each child, analyze their blood type in both the ABO and MN systems. Identify the possible genotypes that could produce the observed phenotype. For example, a child with blood type AB must have the genotype I^A/I^B in the ABO system, and a child with blood type MN must have the genotype M/N in the MN system.
4. Match each child’s genotype to the possible parental genotypes. For example, if a child has the genotype I^A/I^B in the ABO system, one parent must contribute the I^A allele, and the other must contribute the I^B allele. Similarly, for the MN system, if a child has the genotype M/N, one parent must contribute the M allele, and the other must contribute the N allele.
5. Exclude any parental sets that cannot produce the child’s genotype. For example, if a child has the genotype I^A/I^B in the ABO system, a parental set with both parents having the genotype i/i cannot produce this child. Repeat this process for all children and parental sets to determine the matches.

Key Concepts

ABO Blood Group System

The ABO blood group system is determined by three alleles: I^A, I^B, and i. The I^A and I^B alleles are codominant, meaning that if both are present, the phenotype will express both antigens (A and B). The i allele is recessive, leading to the O blood type when homozygous. Understanding how these alleles combine in parents helps predict the possible blood types of their offspring.

MN Blood Group System

The MN blood group system consists of two codominant alleles, M and N. Individuals can have one of three genotypes: MM, MN, or NN, which correspond to the presence of M, N, or both antigens on red blood cells. This codominance means that both alleles can be expressed simultaneously, allowing for a clear distinction in blood type. Knowledge of these genotypes is essential for determining potential parent-child blood type compatibility.

Punnett Squares and Genetic Predictions

Punnett squares are a tool used in genetics to predict the genotypes of offspring based on the alleles of the parents. By laying out the possible combinations of alleles from each parent, one can visualize and calculate the likelihood of various genotypes and phenotypes in the children. This method is crucial for solving problems related to inheritance patterns, such as matching children to potential parents based on blood type.