Question

What is the outcome (in Mendel's work) of crossing two pure-breeding plants with antagonistic (contrasting traits)? only one of the traits will be seen in the progeny both traits will be seen in the progeny both traits will be seen in the progeny in a 3:1 ratio none of the above

Answer 1

the correct answer is- both traits will be seen in the progeny in a 3:1 ratio

Explanation-

Contrasting traits are those that are opposite to one another. For example the contrasting trait of wrinkled pod shape of pea plant is smooth pod.

Let us take an example of the genotypes of smooth pod shape(YY), where the Y allele is homozygously dominant. Contrasting to that the genotype of the wrinkled pod is represented by yy genotype, where the y homozygously recessive.

When YY parent is crossed with yy parent,

The result is-

YY x yy

F1 generation= Yy(all the F1 offsprings will be heterozygous and smooth pod)

When the F1 progenies are self fertilised, they yield the followings:

	Y	y
Y	YY(smooth pod)	Yy (smooth pod)
y	Yy(smooth pod)	Yy(wrinkled pod)

Thus when looking at the phenotypic characteristics, no. of smooth pod pea plant= 3

                                                                                               No. of wrinkled pod pea plant=1

This yields a phenotypic ratio of 3:1