Question

Consider the cross between CcDdEe X ccddEe. What will be the probability of the following respectively?
a) Heterozygous individuals
b) Homozygous individuals
c) Individuals homozygous for first character & heterozygous for second and third character

A) \[\dfrac{4}{{16}},\dfrac{1}{4},\dfrac{2}{8}\]
B) \[\dfrac{2}{{16}},\dfrac{1}{{16}},\dfrac{1}{8}\]
C) \[\dfrac{1}{8},\dfrac{2}{{16}},\dfrac{1}{8}\]
D) \[\dfrac{1}{4},\dfrac{1}{{16}},\dfrac{1}{8}\]

Answer 1

Hint: Homozygous means having the same copies of an allele for example CC, heterozygous means having different copies of a gene for example Cc. In heterozygous one allele is called the dominant and the other is the recessive. The gene expressed will be dominant.

Complete answer:
To solve this question, we must know about the cross and how the pairs will be formed.
In the above question, the cross is done in between CcDdEe X ccddEe
The gametes formed by CcDdEe are CDE, CdE, CDe, Cde, cDE, cdE, cde, cDe
Gametes formed by ccddEe are cde, cdE

Let us make a Punnett square for the calculations. The cross between the two is as follows:

	CDE	CdE	CDe	Cde	cDE	cdE	cde	cDe
cde	CcDdEe	CcddEe	CcDdee	Ccddee	ccDdEe	ccddEe	ccddee	ccDdee
cdE	CcDdEE	CcddEE	CcDdEe	CcddEe	ccDdEE	ccddEE	ccddEe	ccDdEe

Total individual produced =16
A) Heterozygous individuals - (CcDdEe)
B) Homozygous individuals - (ccddee)
C) Individuals homozygous for first character & heterozygous for second and third character or (ccDdEe).

Hence the correct answer is option ‘B’.

Note: Mendel first demonstrated the monohybrid and dihybrid cross in pea plant. On the basis of the results, he formulated three laws of inheritance- Laws of dominance, law of segregation and law of Independent assortment.