Pedigree Charts Quiz 7B

Pedigree Charts Besides showing possible gene pairings, a pedigree chart gives the probability of each pairing. It shows how often, on the average, a given pairing will occur.

Pea Plant Characteristics

Show a cross between a tall and short pea plant Step One Write down the set of contrasting traits. Assign the capitol letter to the dominant trait and the lower case letter to the recessive trait. Tall Short TtTt

Show a cross between a tall and short pea plant Step Two Write down possible genotypes and phenotypes. TT Tt tt Tall Short Purebred dominant hybrid Purebred recessive

Show a cross between a tall and short pea plant Step Three Fill in the genotypes of the parents on the pedigree chart.

Pedigree Chart P1P1 P2P2 F1F1

Parents P1P1 P2P2 In the circle - the possible gametes of the female are listed. In the square - the possible gametes of the male are listed TT tt

Show a cross between a tall and short pea plant Step Four Fill in the genetic possibilities of the F 1 on the pedigree chart.

Cross between a tall and short pea plant P1P1 P2P2 F1F1 T t Take first gene from the female and first gene from the male and place in the first offspring spot. TtTt

Cross between a tall and short pea plant P1P1 P2P2 F1F1 T t Take first gene from the female and second gene from the male and place in the second offspring spot. TtTtTtTt

Cross between a tall and short pea plant P1P1 P2P2 F1F1 T t Take second gene from the female and first gene from the male and place in the third offspring spot. TtTtTtTt TtTt

Cross between a tall and short pea plant P1P1 P2P2 F1F1 T t Take second gene from the female and second gene from the male and place in the fourth offspring spot. TtTtTtTt TtTtTtTt

Show a cross between a tall and short pea plant Step Five Write down the genotypic ratio and the phenotypic ratio. Purebred dominant : Hybrid : Purebred recessive Dominant : Recessive

Cross between a tall and short pea plant P1P1 P2P2 F1F1 T t 0:4:0 TtTtTtTt TtTtTtTt Genotypic Ratio 4:0Phenotypic Ratio