281.

How many different types of gametes are produced, if the genotype of a plant is AABB?

• 8

• 6

• 4

• 2

• 2

Which among these are correctly matched

(i) Down's syndrome - trisomy 21
(ii) Klinefelter's syndrome - 45, XO
(iii) Turner's syndrome -  47x XXY

• (ii) and (iii) only

• (i) only

• (i) and (ii) only

• (iii) only

• (iii) only

What map unit (centimorgan) is adopted in the construction of genetic maps?

• a unit of distance between two expressed genes representing 100%cross over.

• a unit of distance between genes on chromosomes, representing 1% cross over.

• a unit of distance between genes on chromosomes, representing 50% cross over.

• a unit of distance between two expressed genes representing 10% cross over.

A gene locus has two alleles A, a. If the frequency of dominant allele A is 0.4, then what will be the frequency of homozygous dominant, heterozygous and homozygous recessive individuals in the population?

• 0.16 (AA); 0.24 (Aa); 0.36 (aa)

• 0.16 (AA); 0.48 (Aa); 0.36 (aa)

• 0.16 (AA); 0.36 (Aa); 0.48 (aa)

• 0.36 (AA); 0.48 (Aa); 0.16 (aa)

Select the incorrect statement.

• Inmale grasshoppers 50% of sperms have no sex chromosomes.

• In domesticated fowls, sex of progeny depends on the type of sperm rather than egg.

• Human males have one of their sex-chromosome much shorter than the other.

• Male fruit fly is heterogametic.

In Antirrhinum (Snapdragon), a red flower was crossed with a white flower and in F₁ generation pink flowers were obtained. When pink flowers were selfed, the F₂ generation showed white, red and pink flowers. Choose the incorrect statement from the following :

• Pink colour in F₁ is due to incomplete dominance.

• Ratio of F₂ is $\frac{1}{4} \left(\mathrm{Red}\right) : \frac{2}{4} \left(\mathrm{Pink}\right) : \frac{1}{4} \left(\mathrm{White}\right)$

• Law of segregation does not apply in this experiment

• This experiment does not follow the Priniciple of Dominance

The frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes was explained by :

• Gregor J. Mendel

• Alfred Sturtevant

• Sutton Boveri

• T.H. Morgan

Variations caused by mutation, as proposed by Hugo de Vries are

• random and directionless

• small and directional

• small and directionless

• random and directional

What is the genetic disorder in which an individual has an overall masculine development gynaecomastia, and is sterile ?

• Klinefelter's syndrome

• Edward syndrome

• Down's syndrome

• Turner's syndrome