Dihybrid cross Cross Involving 2 characteristics/ genes Ex #3: Characteristic Contrasting traits Seed shape R = Round, r = wrinkled Seed color Y = Yellow, y = green Perform an F1 cross: RrYy X RrYy

Dihybrid cross Ex. Perform a cross between two parents who are heterozygous for both traits: RrYy X RrYy

Dihybrid cross Perform an F1 cross: R r Y y X R r Y y (Use FOIL method to find all gametes.) RY

Dihybrid cross Perform an F1 cross: R r Y y X R r Y y (Use FOIL method to find all gametes.) Ry RY

Dihybrid cross Perform an F1 cross: R r Y y X R r Y y (Use FOIL method to find all gametes.) Ry rY RY

Dihybrid cross Perform an F1 cross: R r Y y X R r Y y (Use FOIL method to find all gametes.) Ry rY ry RY

Dihybrid cross Perform an F1 cross: R r Y y X R r Y y (Use FOIL method to find all gametes.) Ry rY ry RY RY Ry rY ry

Dihybrid cross Perform an F1 cross: R r Y y X R r Y y Ry rY ry RY RY

Dihybrid cross R r Y y X R r Y y Round : Round : wrinkled : wrinkled Yellow green Yellow green R r Y y X R r Y y Ry rY ry RY RY RRYY RRYy RrYY RrYy Ry RRYy RRyy RrYy Rryy rY RrYY RrYy rrYY rrYy ry RrYy Rryy rrYy rryy

Dihybrid cross Round : Round : wrinkled : wrinkled Yellow green Yellow green Ry rY ry RY RY RRYY RRYy RrYY RrYy Ry RRYy RRyy RrYy Rryy rY RrYY RrYy rrYY rrYy ry RrYy Rryy rrYy rryy

Dihybrid cross Round : Round : wrinkled : wrinkled Yellow green Yellow green 9 : 3 : 3 : 1 Ry rY ry RY RY RRYY RRYy RrYY RrYy Ry RRYy RRyy RrYy Rryy rY RrYY RrYy rrYY rrYy ry RrYy Rryy rrYy rryy

Handy Hint: Anytime you perform a dihybrid cross and BOTH parents are heterozygous for BOTH genes, you will ALWAYS get a ratio of: Dominant Dominant Recessive Recessive Dominant recessive Dominant Recessive 9 : 3 : 3 : 1