Which of the following genes are constitutively expressed and control the plantinduced activation of other vir genes?
The principle of metabolic engineering and inheritance explains that exogenous gene introduction and pathway extension enable trait improvement. Hence vir A and vir G fits best because it demonstrates metabolic extension and combinatorial biosynthesis, as documented in authoritative sources on genetics and biotechnology.
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.
