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

Incomplete linkage is due to

  1. epistasis

  2. mutation

  3. cross over

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

Genes present in the same chromosome have a tendency to separate due to crossing over and hence produce recombinant progeny besides the parental type. The number of recombinant individuals is usually less than the number expected in independent assortment. In independent assortment, all the four types (two parental types and two recombinant types) are each 25%. In case of linkage, each of the two parental types is more than 25% while each of the recombinant types is less than 25%.

Multiple choice

"The genes or alleles coming from two different parents tend to enter different gametes and to be inherited independently."

Which phenomenon is defined by the definition mentioned in the passage?

  1. Genetic coupling

  2. Genetic repulsion

  3. Genetic recombination

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

Genetic repulsion is defined as, the genes or alleles coming from two different parents tend to enter different gametes and to be inherited independently.

Multiple choice

Mendel did not notice linkage due to

  1. segregation

  2. dominance

  3. independent assortment

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

Mendel didn't notice linkage due to independent assortment. He unknowingly chose those characters which are either on different chromosomes or lay apart on the same chromosome. The characters were assorted independently in F2 generation as they were not linked.

Multiple choice

Which of the following explanations about a dominant genetic trait subject to genomic imprinting is FALSE?

  1. In a given family, only males or females will be affected.

  2. The trait may appear to skip generations.

  3. Affected individuals will always inherit the mutation from either the mother or father, but not both.

  4. Severity of the phenotype will be independent of sex of the affected individual.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For an inherited trait subject to imprinting, the phenotype will only be expressed when it is inherited from the parent whose copy is expressed in the next generation.

Multiple choice

In predetermining the phenotype for the ABO blood system

  1. blood group O is dominant at blood group A

  2. blood group B is dominant at blood group A

  3. blood type O is recessive

  4. blood type AB is recessive
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The rules of dominance for the ABO system is that both A and B are dominant over O (i.e. O is recessive) and A and B are codominant.

Multiple choice

A person's ABO blood type is typically predetermined by

  1. genetic inheritance and environmental influences during his course of life

  2. environmental factors alone

  3. the inheritance of 1 of 3 possible alleles, i.e. either A, B or O from each of the parent

  4. combination of 2 of 3 possible alleles, i.e. either A, B or O from each of the parent
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In most cases, these alleles are totally responsible for determining blood type phenotypes. The inheritance usually follows simple Mendelian patterns. However, there are rare exceptions such as Bombay Phenotype.

Multiple choice

Select the true statement about Rh positive people.

  1. They are either homozygous dominant (XX) or heterozygous (Xx) for this trait.

  2. They all are homozygous dominant (XX) individuals.

  3. They are all homozygous recessive (xx) individuals.

  4. They are either homozygous recessive (xx) or heterozygous (Xx) for this trait.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Rh blood factor is a dominant trait. Therefore, both DD and Dd people have Rh antigen on the surface of their red cells which make them Rh positive.

Multiple choice

Complete dominance is seen in garden pea plant. What are the possible offsprings when a tall pea plant with yellow seeds (TtYY) is crossed with dwarf pea plant having green seeds (ttyy)?

  1. Tall yellow and dwarf yellow

  2. All are tall yellow.

  3. All are dwarf yellow.

  4. Tall green and dwarf yellow

  5. Tall yellow and dwarf green
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The cross is depicted as follows: Parents: TtYY x ttyy Gametes: TY, tY x ty Offsprings: TtYy and ttYy (ie. Tall yellow and dwarf yellow)