Mendel's Dihybrid Experiment

Q.

A homozygous pea plant bearing yellow (Y) and round seeds (R) is crossed with a homozygous plant bearing green (y) and wrinkled seed (r ) :-

1. Give the genotype and phenotype of the plants of the F₁ generation.
2. Mention the possible combinations of the gametes that can be obtained from the F₁ hybrid plant.
3. State Mendels law of independent assortment.
4. Mention the phenotypes of the offspring obtained in the F₂ generation.
5. What is the phenotypic ratio obtained in F₂ generation?

Q.

Question 43
In the following crosses write the characteristics of the progeny
$\begin{array}{cc}Cross& Progeny\\ \left(a\right)RRYYxRRYY& \\ Round,yellowRound,yellow& .......\\ \left(b\right)RrYyxRrYy& \\ Round,yellowRound,yellow& .......\\ \left(c\right)rryyxrryy& \\ wrinkled,greenwrinkled,green& .......\\ \left(d\right)RRYYxrryy& \\ Round,yellowwrinkledgreen& .......\end{array}$

Q. In dogs, barking and a normal tail is dominant over silent and curly tail. If a barker dog with normal tail which is heterozygous for both the characters is crossed with another dog of same genotype. What fraction of their possible offsprings will be barkers with curly tails?

1. 3/4
2. 9/16
3. 3/16
4. 1/4

Q.

For the given cross, a plant of type 'H' will produce seeds with genotypes identical to the plant ______.
Note: Yellow (Y) is dominant over green (y) and round seed (R) is dominant over wrinkled seed (r).

1. Type N
2. Type M
3. Type U
4. Type S

Q. Albinism in human is controlled by a recessive gene 'a'. If both parents were known to be carriers (Aa) for albinism, what are the chances of 1 normal and 3 albinoes in a family of four?

1. 1/256
2. 12/256
3. 108/256
4. 54/256
5. 81/256

Q.

A cross between pure-bred pea plants having yellow round seeds with those having green wrinkled seeds would produce ${\text{F}}_1$ plants with:

1. Round yellow seeds

2. Wrinkled green seeds

3. Round green seeds

4. Wrinkled yellow seeds

Q. Pure homozygous offsprings in a dihybrid cross in the F${}_2$ generation would be ________.

1. 1/2
2. 1/4
3. 1/8
4. 1/16

Q. The brown eyed condition is dominant over blue eyed in humans. The percentage of organisms born with brown eyes for a cross between $BB\times bb$ will be

1. $0$%
2. $25$%
3. $75$%
4. $100$%
5. $50$%

Q. In a case of mammalian coat color, the principal gene identified is ${}^{\prime }{C}^{\prime }$ which codes for a tyrosinase enzyme. In case of rabbits four different phenotypes are observed.
Full Color > Chinchilla > Himalyan - Albino (in order of the expression of gene ${}^{\prime }{C}^{\prime }$ and its alleles). In a progeny obtained after crossing two rabbits, the percentages of Chinchilla, x-Hunalayan and Albino rabbits were $50,25$ and $25$ respectively What must have been the $C$ genotypes of the parent rabbits?

1. $C^{ch}{C}^{ch}XC{h}^{ch}c$
2. $C^{ch}{C}^{h}XC{h}^{ch}c$
3. $C^{ch}cX{C}^{h}c$
4. $C^h{C}^{h}X{C}^{ch}{C}^{ch}$

Q. Parents are carrier for albinism. What will be the genotype of first three children?

1. All albino
2. Some normal, heterozygous and albino
3. All normal
4. All heterozygous albino

Q.

The gametes produced by the parents of Mendel’s dihybrid cross between a pea plant with yellow round seeds and green wrinkled seeds are:

1. Yr & yR

2. Y, y, R, r

3. Yy & Rr

4. YR & yr

Q. The genotype of ${\text{F}}_1$ hybrids produced by crossing pure yellow round seeded plant (YR) with pure green wrinkled seeded (yr) plant is ___.

1. YyRr
2. YYrr
3. YyRR
4. yyRR

Q. The punnett square shown below represents the pattern of inheritance in a dihybrid cross when yellow seed colour (Y) is dominant over white (y) and round shape (R) is dominant over wrinkled (r) seeds:

A plant of type 'H' will produce seeds with genotypes identical to the seeds produced by the plants of:

1. Type M
2. Type N
3. Type U
4. Type S

Q.

A homozygous plant having round (R) and yellow (Y) seed is crossed with a homozygous plant having wrinkled (r) and green (y) seeds.

Give the genotype of the F₁ generation.