Principles of Inheritance and Variation · Question 91

Which one of the following conditions correctly describes the manner of determining the sex ?

1. XO condition in humans as found in Turner Syndrome, determines female sex
2. XO type of sex chromosomes determine male sex in grasshopper
3. Homozygous sex chromosomes (ZZ) determine female sex in Birds
4. Homozygous sex chromosomes (XX) produce male in Drosophila

Mutations can be induced with :

1. Gamma radiation
2. Infra Red radiations
3. IAA
4. Ethylene

ABO blood grouping is controlled by gene I which has three alleles and shows co-dominance. There are six genotypes. How many phenotypes in all are possible -

1. five
2. four
3. three
4. six

Study the pedigree chart of a certain family given below and select the correct conclusion which can be drawn for the character – [figure]

1. The trait under study could not be colourblindness
2. The female parent is heterozygous
3. The parents could not have had a normal daughter for this character
4. The male parent is homozygous dominant

A cross in which an organism showing a dominant phenotype is crossed with the recessive parent in order to know its genotype is called -

1. Dihybrid cross
2. Back cross
3. Monohybrid cross
4. Test cross

In Antirrhinum two plants with pink flowers were hybridized. The F1 plants produced red, pink and white flowers in the proportion of 1 red, 2 pink and 1 white. What could be the genotype of the two plants used for hybridization? Red flower colour is determined by RR, and White by rr genes -

1. rrrr
2. rr
3. Rr
4. RR

Which one of the following symbols and its representation, used in human pedigree analysis is correct –

1. [figure] = mating between relatives
2. [figure] = unaffected female
3. [figure] = unaffected male
4. [figure] = male affected

ABO blood groups in humans are controlled by the gene I. It has three alleles – IA, IB and i. Since there are three different alleles, six different genotypes are possible. How many phenotypes can occur –

1. One
2. Two
3. Three
4. Four

Select the correct statement from the ones given below with respect to dihybrid cross –

1. Genes far apart on the same chromosome show very few recombinations
2. Tightly linked genes on the same chromosome show very few recombinations
3. Tightly linked genes on the same chromosome show higher recombinations
4. Genes loosely linked on the same chromosome show similar recombinations as the tightly linked ones

The genotype of a plant showing the dominant phenotype can be determined by –

1. Pedigree analysis
2. Back cross
3. Test cross
4. Dihybrid cross