Answer to Question #163821 in Genetics for dia

Question

a)   On crossing a plant with red fruit and hairy stem, with one that was yellow fruit and hairy stem, the following progeny were obtained:

 

           30 red, hairy / 11 red, smooth / 29 yellow, hairy / 9 yellow, smooth

 

Give a reasoned explanation along with the use of full genetic diagrams to proof your answer, to explain these results in terms of the simultaneous transmission of characteristics.

Answer 1

Solution:

A small part of the offspring of plants with hairy stems had smooth stems, which means that the hairy stem trait dominates over the smooth stem trait. One parent plant had red and another had yellow fruits, while the most of the offspring had red fruits. This means that red fruits trait dominate yellow fruits trait. The offspring didn`t have transitional traits, therefore the traits are inherited in a complete dominance.

RR, Rr - red fruit trait

rr - yellow fruit trait

HH, Hh - hairy stem trait

hh - smooth stem trait

The offspring phenotype ratio 30:29:11:9 could be simplified to the ratio 3:3:1:1.

P: RrHh x rrHh

Gametes produced by the first parent: RH, rH, Rh, rh

Gametes produced by the second parent: rH, rh

Punnett square:

The offspring phenotype ratio is 3:3:1:1.

Answer:

Red fruit trait is dominant to yellow fruit trait, hairy stem trait is dominant to smooth stem trait. The traits are inherited in a complete dominance. The parents genotypes are RrHh and rrHh.