Mitochondrial and chloroplast inheritance Original Scenario-Based Download PDF

Questions

1. 1.

   In an isolated alpine reserve, botanists discover a glowing night-blooming herb where leaf luminescence is determined by an organellar mutation. When pollen from a luminescent plant fertilizes the ovule of a wild-type non-luminescent plant, all resulting offspring are non-luminescent. Conversely, reciprocal crosses using pollen from a non-luminescent plant to fertilize a luminescent ovule produce offspring that are all entirely luminescent. Which conclusion is best supported by these experimental outcomes?

   • A) The trait is controlled by an X-linked recessive nuclear allele that is preferentially expressed in female plants.
   • B) The luminescence trait exhibits maternal inheritance because organellar DNA, such as that in chloroplasts, is transmitted solely through the egg cell's cytoplasm.
   • C) The trait is determined by a nuclear gene displaying strict paternal imprinting that silences alleles contributed by the pollen donor.
   • D) The phenotype follows Mendelian autosomal dominance where the seed-bearing parent's nuclear genotype overrides the pollen's genotype.