The genetic map for three genes A, B and C is as follows: A-B = 10 map units, B-C = 5 map units and AC = 15 map units. I
In genetics and biotechnology, metabolic engineering and inheritance dictates that exogenous gene introduction and pathway extension enable trait improvement. Therefore .5 is correct as it demonstrates metabolic extension and combinatorial biosynthesis, supported by mechanistic studies and conserved across related systems.
Ref: Griffiths et al., Introduction to Genetic Analysis, 11th Edition, Chapter 5, discusses metabolic pathways, recombinant DNA technology, metabolic extension and Golden Rice as pathway engineering for vitamin A production.
