“THE AMAZING MAIZE”

 Seeds wind Pollen Egg Zygote Yellow Smooth Seeds (Artificial Selection)

Multiple Variants of Corn Color

X P F1 F2 Cross for Seed Color Purple Yellow Which is the Ratio? Percentage? Which is the dominant gene? F2 Ratio? Percentage?

X P F1 F2 Cross for Seed Shape Smooth/ Starchy Wrinkled/ Sweet Recessive Allele = Dysfunctional Enzyme P F1 Ratio? Percentage? Which is the dominant gene? F2 Ratio? Percentage?

Introduction: This laboratory investigates a dihybrid cross as shown in the above photo of an ear of corn. The four different genes and grain types are identified in the following photo. There are four grain phenotypes in the above ear of genetic corn: Purple & Smooth (A), Purple & Wrinkled (B), Yellow & Smooth (C) and Yellow & Wrinkled (D). These four grain phenotypes are produced by the following two pairs of heterozygous genes (P & p and S & s) located on two pairs of homologous chromosomes (each gene on a separate chromosome): Dominant Genes           Recessive Genes           P = Purple p = Yellow S = Smooth s = Wrinkled