Question

What characteristic should be observed in a pedigree if it signifies mitochondrial diseases, and why?

a) Mitochondrial diseases show a consistent pattern of inheritance through generations due to X-linked genes.
b) Pedigrees of mitochondrial diseases display autosomal recessive inheritance due to gene mutations.
c) Maternal inheritance is evident in pedigrees of mitochondrial diseases because mitochondrial DNA is passed down from the mother.
d) Mitochondrial diseases showcase incomplete penetrance in pedigrees due to multiple gene interactions.

Answer 1

The characteristic that signifies mitochondrial diseases in a pedigree is maternal inheritance due to the exclusive passing down of mitochondrial DNA from the mother.

Step-by-step explanation:

The characteristic that should be observed in a pedigree if it signifies mitochondrial diseases is maternal inheritance. This is because mitochondrial DNA is passed down from the mother. Unlike disorders rooted in autosomal or X-linked genes, mitochondrial conditions result from mutations in the DNA that reside within the mitochondria, which children inherit exclusively from their mothers. When depicting a pedigree for mitochondrial diseases, all offspring of an affected mother can potentially be affected, regardless of their sex, reflecting the pattern of maternal inheritance. Conversely, none of the offspring of an affected father will inherit the disorder, as paternal mitochondria are typically not transmitted to the offspring.