A couple and some of their relatives are screened for Gaucher disease in a community-based screening program. The woman is homozygous for the dominant allele, represented by G. The woman's father, sister, and paternal grandmother are heterozygous carriers of the mutant allele, represented by g. Her paternal grandfather, her mother, and both of her mother's parents are homozygous for the dominant allele. The man is heterozygous and he has a brother with Gaucher disease. The man's parents and grandparents have not been tested, but it is known that none of them has Gaucher disease.
On the pedigree, write the genotypes (GG, Gg, or gg) for each person who has been tested or for whom you can deduce a genotype. If a genotype cannot be determined completely, list the alleles you know or deduce must be present.

Question

On the pedigree, write the genotypes (GG, Gg, or gg) for each person who has been tested or for whom you can deduce a genotype. If a genotype cannot be determined completely, list the alleles you know or deduce must be present.

Accepted Answer

Hi, everyone. Let's take a look at this practice problem together. Gauthier disease is a rare genetic disease that affects the body's ability to break down a fatty substance called glucocerebroside, which accumulates in different organs of the body, especially in the liver, spleen and bone marrow. Gaut disease is inherited as the answer. Options are a, an autosomal dominant pattern. B an ex leaked dominant pattern C, an autosomal recessive pattern and D A mitochondrial inheritance pattern. Now recall that Gauthier disease is caused by a mutation in the GB A gene which codes for the enzyme glucocerebrosidase. The now affected glucocerebrosidase cannot break down the substance glucocerebroside causing its accumulation. Let's discuss each of our answer options and identify the correct answer. We'll start off with a, an autosomal dominant pattern. Now, inheritance curs through a mutated, dominant A lil, this means that all offspring are affected as an individual would only need one mutated ali to be affected. Now, let's discuss option B an X linked dominant pattern. The mutation is inherited by an X chromosome. Therefore, all offspring, regardless if they are male with an X Y chromosome or female with X X chromosomes are affected this is because the mutated X chromosome is dominant to the non affected X chromosome. Now, let's discuss option C and autosomal recessive pattern. This pattern means that only individuals with homozygous recessive genotypes are in are affected. Since inheritance occurs through two mutated recessive allys. Now let's discuss option D A mitochondrial inheritance pattern. Recall that this occurs via the mother's mitochondria and therefore all offspring are affected. So now we've reviewed each of the options. The correct answer is that Gauthier disease is inherited as an autosomal recessive pattern. Therefore, an individual would need two mutated recessive all lies to be affected by Gauthier disease. The correct answer is option C and autosomal recessive pattern. All right, everyone. I hope you found this helpful and I'll see you soon for the next practice problem.

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Key Concepts

Mendelian Inheritance and Allele Dominance

Carrier Status and Genotype Deduction

Pedigree Analysis and Genotype Assignment