Inheritance - 22-07-23

Which of the following statements is true about Mendel?

• His discoveries concerning genetic inheritance were generally accepted by the scientific community when he published them during the mid 19th century.

• He believed that genetic traits of parents will usually blend in their children.

• His ideas about genetics apply equally to plants and animals.

• He discovered linkage

If Mendel had studied the 7 traits using a plant with 12 chromosomes instead of 14, in what way his interpretation would have been different?

• He would have discovered crossing over

• He would have discovered blending or incomplete dominance

• He could not have proposed that genes are carried on chromosomes

• He would not have discovered the law of independent assortment

Individuals homozygous for cd genes were crossed with wild type (++). The F1 dihybrid thus produced was test crossed. It produced progeny in the following ratio –

++ 900

cd 880

+d 115

+c 105

What is distance between c and d

• 5.75 unit

• 11 units

• 27 units

• 88 units

• I - B, II - C, III - A, IV - D

• I - C, II - D, III - A, IV - B

• I - B, II - D, III - C, IV - A

• I - B, II - D, III - A, IV - C

• I - B, II - D, III - A, IV - C

• I - C, II - D, III - A, IV - B

• I - B, II - D, III - C, IV - A

• I - B, II - A, III - D, IV - C

• I - B, II - D, III - A, IV - C

• I - D, II - A, III - B, IV - C

• I - B, II - D, III - C, IV - A

• I - B, II - A, III - D, IV - C

The experiment shown in the figure has been carried out by Morgan to show the phenomenon of linkage and recombination. If in Cross I, genes are tightly linked and in Cross II, genes are loosely linked then what will be the percentage of recombinants produced in Cross I and Cross II respectively?

• 98.7% and 62.8%

• 1.3% and 37.2%

• 37.2 and 1.3%

• 62.8% and 98.7%

X and Y-chromosomes are

• Only morphologically similar

• Only morphologically dissimilar

• Morphologically as well as genetically dissimilar

• None are correct.

Which of the following is suitable for experiments on linkage?

• AABB x aabb

• AaBb x AaBb

• aaBB x aaBB

• AAbb x AaBB

Two linked genes a and b show 20% recombination. The individuals of a hybrid cross between ++/++ x ab/ab shall show gametes:

• ++ 5.0 : ab 50

• ++ 80 : ab 20

• ++ 40 : ab 40 : + a 10 : + b 10

• ++30 : ab 30 : + a 20 : + b 20