Biology

Genetics and Plant Breeding

1,177 Questions

Genetics and Plant Breeding explores the principles of heredity, chromosomal inheritance, and hybridization techniques. It includes key concepts like Mendelian genetics, gene linkage, and polygenic inheritance. This topic is essential for students tackling advanced biology or botany sections in competitive examinations.

Mendelian InheritanceChromosome TheoryGene LinkagePolygenic InheritancePlant HybridizationPopulation Genetics Equilibrium

Genetics and Plant Breeding Questions

Multiple choice pleiotropy genetics zoology

A pleiotropic in Drosophila is that of

  1. Red-white eye

  2. Bar eye

  3. Vestigial gene

  4. Forked bristles.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In Drosophila, the vestigial gene is a classic example of pleiotropy, affecting not only wing size but also haltere size, bristle orientation, and reproductive fitness.

Multiple choice pleiotropy genetics zoology

A $15: 1F _2 $ ratio of a cross between a wheat variety with red kernels (homozygous for two dominant genes) and another with white kernels shows 

  1. Polygenic inheritance

  2. That the two genes are complementary

  3. Single factor inheritance

  4. That it is a tes cross
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

E.Nilsson – Ehle crossed red kernelled variety with white kernelled variety of wheat. The grains of F1 were self crossed among themselves, five different phenotypic classes appeared in F2 showing the ratio of 1:6:15:20:15:6:1.

These scientist found that the kernel colour in wheat is determined by two pairs of genes A and B. It is called polygenic inheritance.

So, the correct option is ‘polygenic inheritance’.

Multiple choice pleiotropy genetics zoology

Occasionally, a single gene may express more than one effect. The phenomenon is called

  1. multiple allelism

  2. mosaicism

  3. pleiotropy

  4. polygeny.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When there are three or more alternative forms of a gene, it is called multiple allelism. Polygeny suggests that humans evolved from several different ancestors. When a single gene has more than one effects, it is called pleiotropy.

So, option C is the correct answer.

Multiple choice pleiotropy genetics zoology

In garden pea, gene controlling starch synthesis related to all of the given phenomenon, except

  1. Pleiotropy

  2. Incomplete dominance

  3. Codominance

  4. Complete dominance
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pleiotropy occurs when one gene influences two or more unrelated phenotypic traits. So, pleitrophy cannot play a role in gene controlling starch synthesis.

Multiple choice pleiotropy genetics zoology

Which of the following is not a pleiotropic gene?

  1. Starch branching enzyme coding gene

  2. Flower colour gene of Pisum sativum

  3. Leaf colour gene of snapdragon

  4. I gene of Blood group
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice pleiotropy genetics zoology

When one gene is responsible for affecting more than one characteristics, the phenomenon is known as

  1. Epistasis

  2. Dominance

  3. Segregation

  4. Pleiotropy

  5. Independent assortment
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Though Mendel through his experiments showcased inheritance of a trait as genetic, some traits results from the combined effect of more than one pair of genes. Contrary to this, a single gene may also be responsible for a variety of traits. This phenomenon is called pleiotropy.

Multiple choice pleiotropy genetics zoology

A gene that shows its effect on more than one character is

  1. Polygene

  2. Pleiotropic gene

  3. Multifactor gene

  4. Multiple gene.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The ability of a gene to produce more than one phenotype in an organism is called Pleoitrophy and the genes are called Pleiotripic genes. It is not essential that the traits are equally influenced. Sometimes, the effect of the gene is more evident in case of one trait and less evident in case of another trait.

So, the correct option is ‘Pleiotropic gene’.

Multiple choice pleiotropy genetics zoology

Same gene loci on two homologous chromosomes produce different phenotypes. They bear

  1. Homozygous alleles

  2. Heterozygous alleles

  3. Two different genes

  4. Pleiotropic genes
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The ability of a gene to have multiple phenotypic effects is known as pleiotropy and the genes are called Pleiotropic genes. These genes influence the number of characters simultaneously. These genes are present on same loci on two homologous chromosomes and produce different phenotypes.

So, the correct option is ‘Pleiotropic genes’.

Multiple choice pleiotropy genetics zoology

A pleiotropic gene is one which

  1. Affects one character

  2. Affects more than one character

  3. Supplements the effect of another gene

  4. Requires another gene for expression
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The ability of a gene to produce more than one phenotype in an organism is called Pleoitrophy and the genes are called Pleiotripic genes. It is not essential that the traits are equally influenced. Sometimes, the effect of the gene is more evident in case of one trait and less evident in case of another trait.

So, the correct option is ‘Affects more than one character’.

Multiple choice pleiotropy genetics zoology

Gene with multiple effects is

  1. Codominant

  2. Pleiotropic

  3. Epistatic

  4. Supplementary
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A.Codominant – appearance of genotypes of both parents in the progeny is called codominance.

B.Pleiotropic - The ability of a gene to have a multiple phenotypic effects is known as pleiotrophy and the gene is called Pleiotropic gene.

C.Epistatic - A gene which masks the action of another gene is termed as epistasis. The gene is called epistatic gene and the gene whose effect is masked is termed as hypostatic gene.

D.Supplementary - genes which include two pairs of non-allelic genes. Both of them are involved in affecting the same character. Out of the non-allelic genes, one gene is dominant and can express by itself. Second gene is also dominant but expresses only when it is supported by the presence of the first gene.

So, the correct option is ‘Pleiotropic’.

Multiple choice pleiotropy genetics zoology

Which is connected with multiple phenotypes?

  1. Epistasis

  2. Pleiotropy

  3. Polygenic inheritance

  4. Mutations
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The ability of a gene to have a multiple phenotypic effects is known as pleiotrophy and the gene is called Pleiotropic gene.

So, the correct option is ‘Pleiotrophy’.

Multiple choice pleiotropy genetics zoology

Multiple phenotype seen in ____________.

  1. Pleitropy

  2. Incomplete dominance

  3. Multiple allelism

  4. Polygenic inheritance
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Pleiotropy occurs when one gene influences two or more seemingly unrelated phenotypic traits. 
  • Such a gene that exhibits multiple phenotypic expression is called a pleiotropic gene.
  • So, (A) is the correct answer.
Multiple choice pleiotropy genetics zoology

Match the columns and choose the correct option

I II
(a) Dominance (i) Many genes govern a single character
(b) Codominance (ii) In a heterozygous organism only one allele expresses itself
(c) Pleiotropy (iii) In a heterozygous organism both alleles express themselves fully
(d) Polygenic inheritance (iv) A single gene influences many characters.

  1. a-iv, b-iii, c-i, d-ii

  2. a-ii, b-i, c-iv, d-iii

  3. a-ii, b-iii, c-iv, d-i

  4. a-iv, b-i, c-ii, d-iii.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

a)Dominance – In a heterozygous organism only one allele express itself

b)Codominance – in a heterozygous organism both alleles express themselves fully

c)Pleiotrophy – A single gene influences many characters.

d)Polygenic inheritance – Many genes govern a single character.

So, the correct option is ‘a-ii b-iii c-iv d-I’.

Multiple choice pleiotropy genetics zoology

Genes showing multiple effects are

  1. Complementary genes

  2. Pseudogenes

  3. Pleiotropic genes

  4. Cistrons
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A.Complmentary genes - Two genes present on separate loci that interact together to produce a dominant phenotype is called Complementary gene.

B.Pseudogenes – Genomic DNA sequences similar to normal genes but non-functional; they are regarded as defunct relatives of functional genes.

C.Pleiotrophic genes - The ability of a gene to have a multiple phenotypic effects is known as pleiotrophy and the gene is called Pleiotropic gene and the inheritance is called Pleiotropic inheritance. Eg:Sickle cell anaemia.

D.Cistrons – Functional parts of the DNA is called Cistron.

So, the correct option is ‘Pleiotropic genes’.

Multiple choice pleiotropy genetics zoology

Pleiotropic gene has

  1. Multiple genotype

  2. Single genotype

  3. Single phenotype

  4. Multiple phenotype
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The ability of a gene to have multiple phenotypic effects or as it influences a number of characters simultaneously is pleiotrophy and the genes are called Pleiotropic genes.

So, the correct option ‘Multiple phenotypes’.