51.

In a plant species, a segregating line (one that contains both homozygotes and heterozygotes at a locus) can be made homozygous by repeated selfing for several generations. What is the level of remaining heterozygosity after three generations of selfing, if the level of heterozygosity in generation'0' is denoted as 1?

• 0.5

• 0.25

• 0.125

• 0.0625

Given below is the result of a complementation test for six independent mutants(1 to 6).

'+' represents complementation; '0' represents non-complementation.

Based on the above, which one of the following conclusions is correct?

• The mutations can be ordered in a single cistron as 1-3-5-2-4-6.

• All mutations belong to a single cistron, but their order cannot be determined.

• There are three cistrons, mutations 1, 3, and 6 represent one cistron, 4 and 5 represent the second cistron and 2 represents the third cistron.

• There are three linkage groups, mutations 1, 3 and 6 represent linkage group A, 4, and 5 represent linkage group B, and 6 represents linkage group C.

In a hospital three babies were mixed up. the blood group of the babies were A, B and AB. In order to identify the parents of the babies the blood groups of the parents were determined. the results obtained were:

Parent set 1 - A and AB

Parent set 2 - AB and O

Parent set 3 - B and AB

Which of the following conclusions can be definitively made?

• The baby with blood group A is the child of the parent set 2.

• The baby with blood group AB is the child of the parent set 1.

• The baby with blood group B is the child of the parent set 3.

• The parentage of none of the babies can be determined from the given information.

There are two mutant plants. One shows taller phenotype than wild type, whereas the other has the same height as the wild type. When these two mutations were brought in together by genetic crosses, the double mutant displayed even taller phenotype than the tall mutant plants. This genetic interaction is called

• antagonistic interaction

• additive interaction

• synergistic interaction

• suppressive interaction

The distribution of heights and weights in a population is shown above in a 2-parameter scatter plot. The size of the square is proportional to the number of persons having a particular combination of weight and height. Which statement best describes the trend in the population?

• Height and weight are strongly correlated.

• Height and weight are anticorrelated.

• Large heights do not imply proportionately large weights.

• Height and weight are independent characteristics.

A cross is made between a pure breeding plant having red coloured flowers with a pure breeding plant having white coloured flowers. Such a cross is called as

• test cross

• monohybrid cross

• dihybrid cross

• back cross

A cis-trans complementation test is carried out to identify

• if two mutations are allelic in nature

• if two genes interact with one another

• the number of genes influencing a phenotype

• to understand the dominance/ recessive relationships between alleles

The following is the inheritance pattern of a trait under observation:

(i) The trait often skips a generation.

(ii) The number of affected males and females is almost equal.

(iii) The trait is often found in pedigree with consanguineous marriages.

The trait is likely to be

• autosomal recessive

• Autosomal dominant

• Sex-linked recessive

• Sex-linked dominant

Greater male investment in the care of offspring is most likely to lead to

• a lek system

• stronger female choice

• reverse sexual dimorphism

• run-away selection

Which of the following representations of chromosomal arrangement in meiotic metaphase I best explains the Law of Independent Assortment?