Principles of Inheritance and Variation Test - 91

The gene having multiple phenotypic effects is called pleiotropic genes, e.g., sickle cell anaemia. Sickle cell anaemia is caused by the gene $$Hb^S$$. When it is in a homozygous condition, sickle cell anaemia occurs or if it is in the heterozygous condition, act as a carrier. Sickle cell anemia causes a rapid breakdown of RBCs results in anaemia, increases heart attack and heart failure chances, also there is an accumulation of blood cells in the liver and spleen which affects the function of the organ.

So, the correct option is '$$Hb^S$$’

A.Mendenlian Inheritance – Transfer of traits from one generation into another into next generation in the form of a particulate structures is called Mendelian Inheritance. Eg: cross based on height or colour and shape of seeds.

B.Monogenic inheritance – It is also called Monohybrid cross. cross between a homozygous dominant parent and a homozygous recessive parent on the basis of single character. Eg:cross based on height of the pea plants.

C.Complementary genes - Two independent pairs of genes, which interact to produce a trait together, but each dominant gene alone does not show its effect, are called complementary genes. eg:cross based on colour of flowers in Sweet potato.

D.Polygenic/Quantitative inheritance - Controlling of a character by two or more genes is called Multifactor inheritance. Eg:inheritance of skin colour of human beings.

So, the correct option is ‘ Polygentc/Quantitative inheritance.

Inheritance is controlled by two or more genes in which the dominant alleles have cumulative effect, with each dominant allele expressing a part of functional polypeptide and full trait is shown when all the dominant alleles are present, is called Polygenic or Quantitative inheritance. In this, different phenotypes are formed not different genotypes.

So, the correct option is Different phenotypes’.

Normally, the flow of genetic information is DNA -> mRNA -> protein. Hence, any change in nucleotide due to mutation would result in change in structure of protein/enzyme. Which in turn might result some change in the organism.

Hugo de Vries, Holland botanist and geneticist, is the author of the mutation theory of evolution. His work led to the rediscovery and establishment of Mendel's laws. He made his first notable contributions to science in the 1880s in the field of plant physiology.

So, the correct option is ‘Holland’.

A.Pedigree analysis – A record of inheritance of certain genetic traits for two or more generations presented in the form of a diagram or family tree is called Pedigree analysis.

B.Punnet square - It is a graphical representation to indicate all possible union of gametes during fertilization and to calculate the probability of all possible genotypes of offsprings in a genetic cross.

C.Chromosome map - a technique used in autosomal DNA testing which allows the testee to determine which segments of DNA came from which ancestor. In order to map DNA segments on specific chromosomes it is necessary to test a number of close family relatives.

D.Genotypic ratio – Ratio, in which the representation of an individual’s genetical constitution with respect to a single character or set of characters.

E.Karyotype - the number and appearance of chromosomes in the nucleus of a eukaryotic cell.

So, the correct option is ‘Punnett square’.

In rice, the green colour of plants is governed by the gene I which is dominant over purple colour. The purple colour is controlled by a dominant gene P. When a cross was made between green (IIpp) and purple (iiPP) colour plants, the F₁ was green. Inter-mating of F1 plants produced green and purple plants in 13 : 3 ratio. Here the allele I isepistatic to alleles P and p. Hence in F2, plants with I-P-(9/16), I-pp (3/16) and iipp (1/16) genotypes will be green because I will mask the effect of P or p. Plants with iiP-(3/16) will be purple, because I is absent.

So, the correct option is ‘suppressor’.