Epistasis Original Scenario-Based Practice

Questions

1. 1.

   A xenobiologist studying bioluminescent spore-fungi (Cryptolux etheria) discovers that glowing requires two unlinked nuclear genes, L and A. The dominant allele L produces an essential luciferin precursor, whereas the homozygous recessive ll produces no precursor, resulting in non-luminous dark caps regardless of alleles at the second locus. In individuals possessing at least one L allele, the dominant allele A converts the precursor into azure light, whereas the recessive genotype aa converts it into amber light. If two dihybrid (LlAa) specimens are crossed, what phenotypic ratio is expected in their offspring, and what specific genetic interaction does this illustrate?

   • A) 9 azure : 3 amber : 4 dark caps, demonstrating recessive epistasis
   • B) 12 azure : 3 amber : 1 dark cap, demonstrating dominant epistasis
   • C) 9 azure : 7 dark caps, demonstrating duplicate recessive epistasis
   • D) 9 azure : 3 amber : 3 glowing green : 1 dark cap, demonstrating independent assortment without epistasis

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