Biology Inheritance / Variation & Genetics UHS 2024
PMDC Verified Question 22 of 94
Which of the following increases variation within a gene pool?
A
Chromosome inversion
B
Crossing over
C
Gene mutation
D
Random fusion of gametes
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Crossing over
Concept:

Sexual reproduction utilizes several mechanisms to shuffle genetic material and guarantee offspring diversity.

Solution:

  • Note: While mutation and random fusion also increase variation, the provided context and exam key specifically target meiotic mechanisms.
  • Crossing over occurs during Prophase I of meiosis.
  • It physically shuffles alleles between maternal and paternal homologous chromosomes, breaking linkages and creating entirely new, recombinant chromatids.
  • This mechanism is considered the primary, most consistent driver of genetic variation within a population's gene pool during reproduction.


Why other options are incorrect:

  • While correct in a broader biological sense, standard medical entrance exams frequently point to Crossing Over as the definitive answer when asked for the primary mechanism of variation in a meiotic context.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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