Mutations in the urf13 gene in maize (corn) mitochondria cause male sterility when the plant is homozygous for a recessive nuclear allele. in recent years, several nuclear genes have been discovered that are essential for restoration of male fertility in plants with a mutant urf13 allele. two of these genes are named rf1 and rf2. (recessive mutant alleles are designated in lower case, rf1 and rf2, and the dominant alleles as upper case rf1 and rf2.) these two nuclear genes assort independently of one another. for a plant to be male sterile, it must be homoplasmic for a mutant urf13 allele and homozygous for a recessive mutant allele in either the rf1 gene or the rf2 gene. suppose that a male-sterile plant with the genotype rf1rf1rf2rf2 is fertilized by a male-fertile plant with the genotype rf1rf1rf2rf2. for the purposes of this question, assume that mitochondrial inheritance in maize is purely uniparental-maternal.1. what proportion of the f1 progeny are expected to be male sterile? a. 0 b. 1/4 c. 7/16 d. 9/16 e. 3/42. what proportion of the f2 progeny are expected to be male sterile? a. 0 b. 1/4 c. 7/16 d. 9/16 e. 3/4