Monohybrid Cross

Monohybrid Cross / Simple Dominance: Question: What are the possible genotypes of the F2 offspring if each parent were from a homozygous line, each expressing a different seed color? Solution: Gene: seed color Alleles: Y= Yellow (dominant) y= green (recessive) P1 (Parental) Cross: Phenotypes: (homozygous yellow seeds) x (homozygous green seeds) Genotypes: (YY) x (yy) Gametes: (Y) & (y) Punnett square F1: Y Y y

y

Yy

Yy

Yy

Yy

Offspring Genotype: Yy Offspring Phenotype: Yellow F1(First generation) Cross: Phenotypes: (heterozygous yellow seeds) x (heterozygous yellow seeds) Genotypes: (Yy) x (Yy) Gametes: (Y) or (y) & (Y) or (y) Punnett square F2: Y y Y

y

YY

Yy

Yy

yy

Offspring Genotype: 1 (YY) 2 (Yy) 1 (yy) Offspring Phenotype: 3 (Yellow) 1 (Green)