Question

A student claims that if the animal producing the spermatozoa has a mutation in a mitochondrial gene, the probability that any offspring will inherit the mutation is zero. Provide evidence to support claim.

Answer 1

Answer:

Mitochondrial DNA is inherited from the maternal side

Explanation:

Mitochondrial DNA is inherited from the maternal side (from the oocyte). The mitochondria from the sperm cell including their DNA are degrade after fertilisation.

The size of the cells that make the zygote also contribute to this. The oocyte is much larger than the sperm, containing around 100,000 mitochondria, whereas the much smaller sperm cell only contains around 100. This means even initially, there are very few paternal mitochondria compared to maternal mitochondria in the first place, effectively diluting them out.

This, coupled with the degradation of the sperm mitochondria, means that offspring will not inherit mitochondrial DNA and any mutations from their father.