Question

In garden peas, round and yellow seeds are controlled by dominant alleles while wrinkled and green seeds are controlled by recessive alleles. If you found a plant with round and yellow seeds and wanted to determine its genotype, you would cross this plant with a plant that is?

Answer 1

Answer:

RrYy x RrYy

Explanation:

Given

Round (R) allele is dominant over wrinkled allele "r"

and Yellow seed allele (Y) is dominant over green seed allele "y"

If I find a plant with round and yellow seeds and want to determine its genotype, then I will cross it with plant that has heterozygous genotype for both the characteristics i.e "RrYy"

Let us say that the plant I found is heterozygous dominant for both the traits i.e "RrYy"

If RrYy is crossed with another RrYy ,we get -

RY        Ry          rY         ry

RY RRYY RRYy RrYY RrYy

Ry RRYy RRyy RrYy Rryy

rY RrYY RrYy rrYY  rrYy

ry RrYy Rryy    rrYy         rryy

Thus, the possible gnotypes would be  

RRYY-1

RRYy-2

RrYY-2

RrYy-4

RRyy- 1

Rryy-2

rrYY-1

rrYy-2

rryy-1

The phenotypic ration for this cross is$9:3:3:1$. This is a standard cross result between two heterozygous parents.