Question

What are the expected phenotypic ratio from the following cross: Tt Rr Yy Aa x Tt rr Yy Aa, where T= tall, t=dwarf, R=round, r= wrinkled, Y=yellow, y=green, A=axial, a=terminal; T, R, Y and A are dominant alleles.

Answer 1

Answer:

Multiplication method can be used to determine this

Tt Rr Yy Aa x Tt rr Yy Aa

For height (Tt x Tt) the phenotypic ratio is 3:1 (3 tall : 1 dwarf)

For Shape (Rr x rr) the phenotypic ratio is 1:1 (1 round : 1 wrinkled)
For Color (Yy x Yy) the phenotypic ratio is 3:1 (3 Yellow : 1 green)

For Flower location (Aa x Aa) the phenotypic ratio is 3:1 (3 Axial : 1 terminal)

Therefore the product is:

(3 tall + 1 dwarf)* (1 round + 1 wrinkled)*(3 Yellow + 1 green)* (3 Axial + 1 terminal)

= (3 tall1 round + 3 tall1 wrinkled + 1 dwarf1 round + 1 dwarf 1 wrinkled)*(3 Yellow3 Axial + 3 Yellow1 terminal +1 green3 Axial + 1 green1 terminal )

• 27 tall, round, Yellow, Axial
• 9 tall, round , Yellow, terminal
• 9 tall, round, green, Axial
• 3 tall, round, green, terminal

• 27 tall, wrinkled, Yellow, Axial
• 9 tall, wrinkled, Yellow, terminal
• 9 tall, wrinkled, green, Axial
• 3 tall, wrinkled, green, terminal

• 9 dwarf, round, Yellow, Axial
• 3 dwarf, round, Yellow, terminal
• 3 dwarf, round, green, Axial
• 1 dwarf, round, green, terminal

• 9 dwarf, wrinkled, Yellow, Axial
• 3 dwarf, wrinkled, Yellow, terminal
• 3 dwarf, wrinkled, green, Axial
• 1 dwarf, wrinkled, green, terminal