The first genetic maps that were developed used genes as markers because
This outcome reflects metabolic engineering and inheritance, where exogenous gene introduction and pathway extension enable trait improvement. Option A captures this correctly because it demonstrates metabolic extension and combinatorial biosynthesis, consistent with textbook descriptions and experimental observations in genetics and biotechnology.
Ref: Pierce, Genetics: A Conceptual Approach, 6th Edition, Chapter 3, discusses genotype-phenotype correlation and inheritance patterns providing framework for genetic transmission and metabolic engineering.
