Principles of Inheritance and Variation

A gene is said to be dominant if : -

1. It is expressed only in heterozygous condition
2. It expresses its effect only in homozygous stage
3. It is never expressed in any condition
4. It is expressed both in homozygous and heterozygous condition

A diseased man marries a normal woman. They get three daughters and five sons. All the daughters were diseased and sons were normal. The gene of this disease is : -

1. Sex linked dominant
2. Autosomal dominant
3. Sex linked recessive
4. Sex limited character

Which of the following is a correct match -

1. Sickle cell anaemia = X – Chromosome
2. Down Syndrome = 21st Chromosome
3. Haemophilia = Y – Chromosome
4. Parkinson Disease = X & Y Chromosome

Change in sequence of nucleotide in DNA is called as -

1. Recombination
2. Mutation
3. Mutagen
4. Translation

If a diploid cell is treated with colchicine then it becomes : -

1. Tetraploid
2. Monoploid
3. Diploid
4. Triploid

Two non-allelic genes produce the new phenotype when present together but fail to do so independently then it is called

1. Polygene
2. Complementary gene
3. Non-complementary gene
4. Epistasis

A and B genes are linked. What shall be genotype of progeny in a cross between AB/ab and ab/ab?

1. AABB and aabb
2. None
3. AaBb and aabb
4. AAbb and aabb

When dominant and recessive alleles express themselves together it is called

1. Dominance
2. Pseudo dominance
3. Co-dominance
4. Amphidominance

Ratio of complementary genes is

1. 9 : 3 : 4
2. 9 : 7
3. 12 : 3 : 1
4. 9 : 3 : 3 : 4

Independent assortment of genes does not take place when

1. Genes are located on non-homologous chromosomes
2. Genes are linked and located on same chromosome
3. Genes are located on homologous chromosomes
4. All the above