Question

Total 512 seeds are collected from the cross “Ww Yy” x “Ww Yy”, find the number of plants produced with first dominant & second recessive.
A. 288
B. 96
C. 52
D. 320

Answer 1

Hint: Here, we have to find plants that will be phenotypically dominant for the first trait and phenotypically recessive for the second trait.

Complete answer: In order to predict the genotype of a cross during a breeding experiment or process we need to first draw a “Punnett square”. From the Punnett square, we can predict all possible outcomes of a cross, therefore, it can clearly be used to find out the answer of the above-said question of finding out the first dominant and second recessive gene.

ALLELES	Wy	Wy	Wy	Wy
Wy	Wwyy	Wwyy	Wwyy	Wwyy
Wy	Wwyy	Wwyy	Wwyy	Wwyy
Wy	Wwyy	Wwyy	Wwyy	Wwyy
Wy	Wwyy	Wwyy	Wwyy	Wwyy

From the above Punnett square of WwYy$\times $WwYy, it can be clearly concluded that 3 out of 16 have first dominant and second recessive traits as underlined. So, out of 512 seeds, number of seeds with first dominant & second recessive traits is \[\left( \text{512}\times \text{3} \right)\text{/16}=\text{96}\].
So, the correct answer is option B.

Additional information: Punnett square is a square diagram that is used to predict the genotypes of a particular cross. It is named after Reginald C. Punnett. A Punnett square allows one to predict the percentage of the genotype in the offspring of a cross from known genotypes.

Note: When an allele is dominant, the characteristic it is connected to will be expressed in an individual, and when the allele is recessive, it is unlikely to be expressed. An allele is a variant form of a gene.