TheEinstein
Answered

HELP, BIG POINTS!!! Long stems (T) are dominant over short stems (t) for pea plants. Determine the phenotypic and genotypic ratios of the offspring from the (Hint: draw Punnett squares, phenotypic ratios should be in the format similar to 1 Long : 1 Short and genotypic ratios should be in the form similar to 1 TT : 1 Tt : 1 tt) Be sure to reduce the ratios to lowest terms (for example, 2 : 2 reduces to 1:1):

Across-pollination of a heterozygous long-stem plant with a short stem plant.

Phenotypic Ratio:


Genotypic Ratio:

Bself-fertilization of a heterozygous plant

Phenotypic Ratio:


Genotypic Ratio:

  1. Cystic fibrosis is regulated by a recessive allele, c. Explain (do not just fill in the Punnet square below) how two normal parents can produce a child with this disorder. Be sure to include the genotype of a child with cystic fibrosis. (Hint: give the genotypes of the normal parents and show that a cross is possible to result in a cystic fibrosis offspring).

Verified Answer :

ACross:   Tt    ×    tt
Offspring: Tt, Tt, tt, tt

1) Phenotypic ratio: Long: Stem = 2:2 = 1:1

2) Genotypic ratio: TT : Tt : tt = 0 : 2 : 2

b) Cross: Tt     ×    Tt
Offspring:  TT, Tt, Tt, tt

1) Phenotypic ratio: Long: stem = 3 : 1

2) Genotypic ratio: TT : Tt : tt = 1 : 2 : 1

4) Cystic fibrosis is regulated by a recessive allele, it means, it would be "Active" when both the allele will be same in the Offspring. So, let father transmits "Y" chromosome to his son, and mother "X" if they both were carrier of this disease, then they will inherit it to their offspring.

Genotype: XcXc or XcY

Hope this helps!