Practice question

Mendelian deviations attributed to gene interaction arise from functional convergence rather than physical linkage, chromosomal aberrations or elevated mutation rate. Two loci residing on different chromosomes can assort independently yet enzymes they encode act sequentially in same biosynthetic cascade causing phenotypic dependency. If either enzyme missing final product absent; if inhibitor present upstream downstream expression suppressed. Genes are non-allelic but influence same pathway, so phenotype reflects combined activity not gamete frequency. Linkage alters gamete frequencies reducing recombinants, whereas interaction alters phenotype mapping despite normal segregation and independent assortment.