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Free Gene Linkage and Crossing Over MCQs with Answers

27 Gene Linkage and Crossing Over MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

Linked genes lie on the same chromosome and tend to pass together, unlike genes that assort independently on different chromosomes. The topic connects linkage with homologous pairing, crossing over during prophase I of meiosis, recombinant and parental offspring, and recombination frequency as an estimate of gene distance.

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21. The chance of a cross-over between two loci is directly proportional to their:

  • A. Length
  • B. Width
  • C. Distance
  • D. Thickness

Explanation: The value of Cross over or recombination frequency is directly proportional to the distance between the genes on the gene map.

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Correct answer: Distance

22. Locus of a gene on a chromosome means its:

  • A. Position
  • B. Function
  • C. Start point
  • D. End point

Explanation: The locus of a gene on a chromosome refers to its specific location or position on the chromosome.

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Correct answer: Position

23. What is the name of the process by which genetic material is shuffled during meiosis, increasing genetic variation?

  • A. Mutation
  • B. Genetic drift
  • C. Crossing over
  • D. Gene flow

Explanation: Crossing over is the process by which segments of DNA are exchanged between homologous chromosomes during meiosis, resulting in increased…

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Correct answer: Crossing over

24. The phase of meiosis during which the non-sister chromatids of homologous chromosomes may exchange their segments:

  • A. Leptotene
  • B. Pachytene
  • C. Diplotene
  • D. Zygotene

Explanation: Leptotene is the first stage of the prophase of meiosis, during which each chromosome becomes visible as two fine threads.

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Correct answer: Pachytene

25. Synaptonemal complex helps in:

  • A. Gamete formation
  • B. Recombination during cell division
  • C. Production of enzymes during cell division
  • D. Chromosomal movement towards pole

Explanation: The synaptonemal complex plays a crucial role in several processes related to cell division, particularly during meiosis, which is the…

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Correct answer: Recombination during cell division

26. The process of determining the locus for particular biological traits includes?

  • A. Replication
  • B. Recombination
  • C. Gene mapping
  • D. None of these

Explanation: Option A: Replication refers to the process of DNA replication that occurs before cell division.

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Correct answer: Gene mapping

27. Law of independent assortment cannot be applied on:

  • A. Dominant genes
  • B. Recessive genes
  • C. Linked genes
  • D. Autosomal genes

Explanation: When the two homozygous parents differing in two pairs of contrasting traits are crossed, the inheritance of one pair is independent of…

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Correct answer: Linked genes
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