Suppose in humans an autosomal gene, 𝑎, causes dwarfism in one homozygous state (𝑎𝑎), normal height in the heterozygous state (𝑎𝑎−), and is embryonic lethal in the other homozygous state (𝑎−𝑎−). A separate gene, 𝑝, found on another chromosome causes albinism, an autosomal recessive disorder. Albino individuals have the 𝑝−𝑝 genotype. Rick and Lori, who are both heterozygous for both genes (𝑎𝑎−𝑝𝑝−), just had a son, Carl. What is the probability that Carl is a dwarf with albinism? Probability: To determine the probability that Carl is a dwarf with albinism, we need to consider the inheritance patterns of both genes. For the gene 𝑎, we know that Rick and Lori are both heterozygous (𝑎𝑎−). This means that there is a 50% chance that they will pass on the 𝑎 allele to Carl. Since dwarfism is caused by the homozygous state (𝑎𝑎), Carl will only be a dwarf if he inherits the 𝑎 allele from both Rick and Lori. For the gene 𝑝, we know that Rick and Lori are both heterozygous (𝑝𝑝−). This means that there is a 50% chance that they will pass on the 𝑝 allele to Carl. Since albinism is caused by the homozygous recessive state (𝑝−𝑝−), Carl will only have albinism if he inherits the 𝑝 allele from both Rick and Lori. To calculate the probability that Carl is a dwarf with albinism, we need to multiply the probabilities of inheriting the 𝑎 allele and the 𝑝 allele. Probability of inheriting the 𝑎 allele: 0.5 Probability of inheriting the 𝑝 allele: 0.5 Probability of being a dwarf with albinism: 0.5 * 0.5 = 0.25 Therefore, the probability that Carl is a dwarf with albinism is 0.25 or 25%.

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