Albinism in humans is inherited as a simple recessive trait. For the following families, determine the genotypes of the parents and offspring. (When two alternative genotypes are possible, list both.)
Two normal parents have five children, four normal and one albino.

Verified step by step guidance

1. Identify the inheritance pattern: Albinism is a recessive trait, so the genotype for albinism is homozygous recessive (aa), and normal pigmentation can be either homozygous dominant (AA) or heterozygous (Aa).
2. Since two normal parents have an albino child, both parents must carry the recessive allele. Therefore, both parents' genotypes must be heterozygous (Aa).
3. Determine the possible genotypes of the children using a Punnett square for parents with genotypes Aa x Aa. The possible genotypes for offspring are AA, Aa, and aa.
4. List the expected genotypes of the children: four normal children can be either AA or Aa, and one albino child must be aa.
5. Summarize the genotypes: Parents are both Aa; offspring genotypes are four normal (AA or Aa) and one albino (aa).

Key Concepts

Recessive Inheritance

Recessive inheritance means a trait appears only when an individual has two copies of the recessive allele. In albinism, the trait is recessive, so a person must inherit the albino allele from both parents to express the condition.

Genotype vs. Phenotype

Genotype refers to the genetic makeup (allele combination) of an organism, while phenotype is the observable trait. Normal parents can carry recessive alleles without showing albinism, affecting the genotypes and phenotypes of their children.

Punnett Square and Probability

A Punnett square helps predict offspring genotypes from parental alleles. It shows the probability of inheriting dominant or recessive traits, which is essential to determine possible genotypes of parents and children in this family scenario.