Five bacterial markers were followed for a co-transduction experiment. The following table documents the observations of this experiment. '+' denotes co-transduction and '-' denotes lack thereof; 'ND' stands for not determined.

Pick the correct order in which the genes are arranged on the bacterial chromosome

• str - gal - leu - arg - met

• leu - met - arg - str - gal

• leu - str - met - gal - arg

• arg - gal - str - leu - met

A male mouse cell line has a large translocation from X chromosome into chromosome 1. When a GFP containing transgene is inserted in this chromosome 1 with translocation, it is often silenced. However, when inserted in the other homologue of chromosome 1 that does not contain the translocation, it is almost always expressed. Which of the following phenomenon best describes this effect?

• Genome imprinting

• Gene balance

• Sex-specific expression

• Dosage compensation

Two interacting genes (independently assorting) were involved in the same pathway. Absence of either gene's function leads to the absence of the end product of the pathway. A dihybrid cross involving the two genes is carried out. What fraction of the F₂ progeny will show the presence of the end product?

• 1/4

• 3/4

• 9/16

• 15/16

A three-point test cross was carried out in Drosophila melanogaster involving three adjacent genes X, Y, and Z, arranged in the same order. The distance between X to Y is 32.5 map unit (mu) and that between X to Y is 20.5 map. The coefficient of coincidence = 0.886. What is the percentage of double recombinants in the progeny obtained from the testcross?

• ∼6%

• ∼8%

• ∼12%

• ∼16%

Fruit color of wild Solanum nigrum is controlled by two alleles of a gene (A and a). The frequency of A, p = 0.8 and a, q = 0.2. In a neighbouring field a tetraploid genotype of S. nigrum was found. After critical examination five distinct genotypes were found; which are AAAA, AAAa, AAaa, Aaaa and aaaa. Following Hardy Weingberg principle and assuming the same allele frequency as that of diploid population, the numbers of phenotypes calculated within a population of 1000 plants are close to one of the following:

AAAA : AAAa : AAaa : Aaaa : aaaa

• 409 : 409 : 154 : 26 : 2

• 420 : 420 : 140 : 18 : 2

• 409 : 49 : 144 : 36 : 2

• 409 : 420 : 144 : 25 : 2

Poplar is a dioecious plant. A wild plant with 3 genes AABBCC was crossed with a triple recessive mutant aabbcc. The F₁ male hybrid (AaBbCc) was then backcrossed with the triple mutant and the phenotypes recorded are as follows:

AaBbCc	300
aaBbCc	100
aaBbcc	16
AabbCc	14
AaBbcc	65
aabbCc	75
aabbcc	310
Aabbcc	120

The distance in map unit (mu) between A to B and B to C is 

• 25 and 17 mu, respectively

• 33 and 14 mu, respectively

• 25 and 14 mu, respectively

• 33 and 17 mu, respectively

Which one of the following statements is incorrect?

• Loss of genetic variation occurs within a small population due to genetic drift.

• The number of deleterious alleles present in the gene pool of a population is called the genetic load.

• Genetic erosion is a reduction in levels of homozygosity.

• Inbreeding depression results from increased homozygosity for deleterious alleles.

108.

A mouse carrying two alleles of insulin-like growth factor II (IgF2) is normal in size; whereas a mouse that carries two mutant alleles lacking the growth factor is dwarf. The size of a heterozygous mouse carrying one normal and one mutant allele depends on the parental origin of the wild type allels. Such pattern of inheritance is known as

• Sex-linked inheritance

• Genomic imprinting

• Gene-environment interaction

• Cytoplasm inheritance

Which one of the following statements is INCORRECT?

• Quantitative inheritance results in a range of measurable phenotypic for a polygenic trait.

• Polygenic traits often demonstrate continuous variation.

• Certain alleles of quantitative trait loci (QTL) have an additive effect on the character/ trait.

• Alleles governing quantitative traits do not segregate and assort independently.

Maternal inheritance of coiling of shell in snail (Limnaea peregra) is well established. The dextral coiling depends on dominant allele D and sinistral coiling depends upon recessive allele d. A female F1 progeny of dextral (Dd) type is crossed with a male sinistral snail. What will be the ratio of heterozygous: homozygous individuals in its F2 progeny?

• 3 : 1

• 1 : 1

• 1 : 3

• 1 : 2 :