Freckles are dominant to plain skin and the freckle gene is on an autosome. Becker muscular dystrophy is inherited as X-linked recessive trait. The parents are healthy and both have freckles. They have an affected son with plain skin. Draw up the family pedigree. Find the genotypes. a) What is the chance that they will have a daughter who has the disease and who has freckles? Inheritance of Freckles and Becker Muscular Dystrophy: Analyzing a Family Pedigree

Inheritance of Freckles and Becker Muscular Dystrophy: Analyzing a Family Pedigree

A family with a son affected by Becker muscular dystrophy (BMD) is presented. It is known that the parents are healthy and both have freckles. The son, however, has plain skin. To analyze the family pedigree, it is important to first understand the genetic basis of freckles and BMD. Freckles are caused by a dominant gene located on an autosome, while BMD is inherited as an X-linked recessive trait (Kremer, 2018; Aitken et al., 2020). To calculate the chance of the couple having a daughter affected by BMD and with freckles, we must first determine the genotypes of each family member. It is known that the parents are both heterozygous for the freckles gene, and that the son is homozygous recessive for the freckles gene. The father’s genotype for the BMD gene is unknown, but the mother must be either heterozygous or homozygous recessive (Aitken et al., 2020). The chance of the couple having a daughter affected by BMD and with freckles is determined by the genotype of the mother. If the mother is heterozygous for the BMD gene, then there is a 25% chance of having a daughter with both traits. If the mother is homozygous recessive for the BMD gene, then there is a 0% chance of having a daughter with both traits (Kremer, 2018). Cont…