Question

In peas, Tall (T) is dominant over dwarf (t), Yellow is dominant over green (y), and Smooth (S) is dominant over wrinkled (s). What fraction of the offspring in the following cross would be homozygous recessive for all gene pairs in the cross: YyTtss x YyttSs?

Answer 1

here it is given that there are two characteristics of each... So we will make punett's square to find the ratio.......

Answer 2

Answer: The correct answer is - 1/16

Explanation-

As per the question, tall height (T), yellow color( Y) , and smooth (S) are dominant traits over dwarf (t), green color (y), and wrinkled (s) phenotype.

Homozygous recessive means both the alleles ( different forms of a gene) are  recessive ( like tt for dwarf). The genotypes of parents are- YyTtss and YyttSs.

There are four gametes produced by each parent.

Gametes produced by parent YyTtss are YTs, Yts, yTs, yts whereas gametes produced by parent YyttSs are YtS, Yts, ytS, yts.

When the parents are crossed, fraction of homozygpous recessive for all gene pair ( that is yyttss) produced is 1/16.