Question

In a homozygous pea plant, axial flowers (A) are dominant over terminal flowers (a).

1. What is the phenotype and genotype of the F₁ generation if a plant bearing pure axial flowers is crossed with a plant bearing pure terminal flowers?
2. Draw a Punnett square board to show the gametes and offsprings when both the parent plants are heterozygous for axial flowers.
3. What is the phenotypic ratio and genotypic ratio of the above cross shown in (b)?
4. Name two genetic disorders commonly seen in human males.

Answer 1

1. Phenotype: All bear axial flowers.
   Genotype: All are heterozygous dominant for axial flowers.
2. 
   

   Gamets	A	a
   A	AA	Aa
   a	Aa	aa

3. Phenotypic ratio: 3 : 1
   Genotypic ratio: 1 : 2 : 1
4. 1. Colour blindness
   2. Haemophilia