Tag: trihybrid cross

Questions Related to trihybrid cross

Number of phenotypes possible from AaBbCc $\times$ AaBbCc is

trihybrid cross classical genetics botany

  1. 16

  2. 12

  3. 8

  4. 4

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Correct Option: C
Explanation:

When a cross is made between AaBbCc with AaBbCc, in the next generation 8 types of phenotypes appear, because this cross involves 3 pairs of contrasting characters 2n, n means number of pairs of characters.

Here 3 pairs of characters are present, 23 = 8.

So, the correct option is ‘8’.

How many types of gametes will be produced by individuals of AABbcc genotype?

trihybrid cross classical genetics botany

  1. Two

  2. Four

  3. Six

  4. Nine

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Correct Option: A
Explanation:

The plant with genotype AABbcc produces only two types of namely ABc, Abc, because it shows one pair of contrasting characters.

So, the correct option is ‘Two’.

How many types of gametes are expected from the organism with genotype AA BB CC?

trihybrid cross classical genetics botany

  1. One

  2. Two

  3. Four

  4. Eight

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Correct Option: A
Explanation:

AABBCC is trihybrid homozygous organism. This organism at the time of fertilization produces only one type of gametes. They are ABC.

So, the correct option is ‘one’.

The trihybrid phenotypic ratio of $27:9:9:9:3:3:3:1$ is obtained because of.

trihybrid cross classical genetics botany

  1. Multiple alleles

  2. Interaction of genes

  3. Multiple factor inheritance

  4. Independent assortment of genes

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Correct Option: A

A plant of F$ _{1}$-generation is having the genotype "AABbCC". On selfing of this plant, what is the phenotypic ratio in F$ _{2}$-generation?

trihybrid cross classical genetics botany

  1. 3 : 1

  2. 1 : 1

  3. 9 : 3 : 3 : 1

  4. 27 : 9 : 9 : 9 : 3 : 3 : 3 : 1

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Correct Option: A
Explanation:

It is given that the f$ _1$ generation is having genotype AABbCC. The gametes of these parents will contain ABC and AbC alleles. On selfing of this plant, the phenotypic ratio of F$ _2$ generation will be 3:1. Similarly, the genotypic ratio of the F$ _2$ generation will be 1:2:1 where one part will be AABBCC. 2 parts will be AABbCC and 1 part will be AAbbCC.

Thus, the correct answer is '3:1.'

What proportion of the offsprings obtained from cross $AABBCC \times AaBbCc$ will be completely heterozygous for all the genes segregated independently?

trihybrid cross classical genetics botany

  1. $1/8$

  2. $1/4$

  3. $1/2$

  4. $1/16$

Show answer
Correct Option: A
Explanation:

Since one parent is homozygous AABBCC  the genotype formed will be only 1 type i.e. ABC. The other parent is heterozygous for all genes. About 1/8th or 12.5% of total offspring will be heterozygous at all three-locus.


So the answer is '1/8'. 

Find out the number of plants produced with genoptype AabbCc out of 256 seeds collected from $F 2$ progennines of a trihybrid cross ______.

trihybrid cross classical genetics botany

  1. 32

  2. 16

  3. 12

  4. 8

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Correct Option: B

Frequency of recombinant plants in the $F _2$ generation of a trihybrid cross is?

trihybrid cross classical genetics botany

  1. $42.18\%$

  2. $96.8\%$

  3. $56.25\%$

  4. $43.75\%$

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Correct Option: A

The offspring of AA bb $\times$ aa BB is crossed with, aabb. The genotypic ratio of progeny will be

trihybrid cross classical genetics botany

  1. 9 : 3 : 3 : 1

  2. 1 : 2 : 1

  3. 1 : 1 : 1 : 1

  4. 4 : 1

Show answer
Correct Option: C
Explanation:

The cross is made between AAbb to aaBB. The progeny formed shows the genotype AaBb. This progeny is crossed with aabb. The genotypes of the progeny are 4 AaBb, 4Aabb, 4aaBb, 4aabb. The genotypic ratio is 1:1:1:1.

So, the correct option is ‘1:1:1:1’.

What percentage of offsprings would have the genotype AA Bb Cc in F2 generation of a trihybrid cross __________.

trihybrid cross classical genetics botany

  1. 12.5%

  2. 6.25%

  3. 25%

  4. 37.5%

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Correct Option: A