Principles of Inheritance and Variation

The most popularly known blood grouping is the ABO grouping. It is named ABO and not ABC, because "O" in it refers to having:

1. Other antigens besides A and B on RBCs
2. No antigens A and B on RBCs
3. Overdominance of this type on the genes for A and B types
4. One antibody only – either anti-A or anti-B on the RBCs

Study the pedigree chart given below: [figure] What does it show?

1. Inheritance of a recessive sex-linked disease like haemophilia
2. Inheritance of a sex-linked inborn error of metabolism like phenylketonuria
3. The pedigree chart is wrong as this is not possible
4. Inheritance of a condition like phenylketonuria as an autosomal recessive trait

Which one of the following conditions in humans is correctly matched with its chromosomal abnormality/linkage?

1. Klinefelter's syndrome — 44 autosomes + XXY
2. Colour-blindness — Y-linked
3. Down syndrome — 44 autosomes + XO
4. Erythroblastosis foetalis — X-linked

Haploids are more suitable for mutation studies than the diploids. This is because:

1. all mutations, whether dominant or recessive are expressed in haploids
2. mutagens penetrate in haploids more effectively than in diploids
3. haploids are reproductively more stable than diploids
4. haploids are more abundant in nature than diploids

A human male produces sperms with the genotypes AB, Ab, aB, and ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person?

1. AaBb
2. AABB
3. AaBB
4. AABb

In pea plants, yellow seeds are dominant to green. If a heterozygous yellow seeded plant is crossed with a green seeded plant, what ratio of yellow and green seeded plants would you expect in F1 generation?

1. 9 : 1
2. 3 : 1
3. 50 : 50
4. 1 : 3

Inheritance of skin colour in humans is an example of:

1. Chromosomal aberration
2. Polygenic inheritance
3. Codominance
4. Point mutation

In the hexaploid wheat, the haploid (n) and basic (x) numbers of chromosomes are:

1. n = 21 and x = 14
2. n = 21 and x = 21
3. n = 7 and x = 21
4. n = 21 and x = 7

A common test to find the genotype of a hybrid is by:-

1. Crossing of one F1 progeny with recessive parent
2. Crossing of one F2 progeny with female parent
3. Crossing of one F2 progeny with male parent
4. Studying the sexual behaviour of F1 progenies

Both sickle cell anemia and Huntington's chorea are-

1. Congenital disorders
2. Bacteria-related diseases
3. Virus-related diseases
4. Pollutant-induced disorders