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

A couple went for molecular testing for prenatal diagnosis of an autosomal recessive trait. The haplotype in coupling with the mutation is found in both of them by analysis of the parents and the affected child. The analysis of chorionic villus tissue from the developing embryo reveals that the embryo inherited only the maternal haplotype in coupling with the mutation. The counselling to them would be

  1. The child will be a carrier.

  2. The child will be affected if recombination takes place in the father only.

  3. The child will be homozygous unaffected if recombination takes place in the mother.

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Yes, all the statements are correct.

Multiple choice

Hypophosphatemia is manifested by an X-linked dominant allele. What proportion of the offsprings from a normal male and an affected heterozygous female will manifest the disease?

  1. ½ sons and ½ daughters

  2. all daughters and no sons

  3. all sons and no daughters

  4. ¼ daughters and ¼ sons
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For an X-linked dominant disorder: affected female (X^A X^a) × normal male (X^a Y). Each child gets one X chromosome from the mother (either X^A or X^a, 50% probability) and either X^a or Y from the father. Daughters: 50% will be X^A X^a (affected), 50% will be X^a X^a (normal). Sons: 50% will be X^A Y (affected), 50% will be X^a Y (normal). Therefore, 50% of sons and 50% of daughters will manifest the disease. This matches option A. Option B would describe X-linked dominant inheritance from an affected father, while option C would describe Y-linked inheritance (which doesn't apply here).

Multiple choice

Mendel did not postulate about _________.

  1. dominance

  2. segregation

  3. linkage

  4. independent assortment

  5. monohybrid cross
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Linkage is the tendency of genes that are located proximal to each other on a chromosome to be inherited together during meiosis. It was given by Bateson.