Question

One of the parents of a cross has mutation in its mitochondrion. In that cross, that parent is taken as male. During segregation of $F_2$ progenies that mutation is found in

• A. One third of the progenies
• B. None of the progenies
• C. All the progenies
• D. Fifty percent of the progenies

Answer 1

Answer: (B)

None of the progenies

Answer 2

Mutation is a sudden alteration of the chemical structure of a gene or the alteration of its position on the chromosome by breaking and rejoining of the chromosome. It has occured in male parent. But organelles like mitochondria, chloroplast etc. are a part of cytoplasmic inheritance. Cytoplasmic inheritance is the passage of traits from parents to offspring through structures present inside the cytoplasm of contributing gametes. Plasma genes occur in plastids, mitochondria, plasmids and some special particles like kappa particles, sigma particles, etc. In higher organisms cytoplasmic inheritance is called maternal inheritance because the zygote receives most of its cytoplasm from the ovum. Therefore, cytoplasmic inheritance is usually unparental.So none of the progeny will show mutation.