Biology Inheritance / Variation & Genetics MDCAT 2018
PMDC Verified Question 84 of 94
Chance of a cross over between two loci is directly proportional to their:
A
Length
B
Width
C
Distance
D
Thickness
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Distance
Concept:

Genetic mapping relies on the frequency of recombination between linked genes.

Solution:

  • During meiosis, crossing over occurs between non-sister chromatids.
  • The physical distance separating two gene loci on a chromosome directly dictates how likely a chiasma will form between them.
  • The value of crossing over or recombination frequency is directly proportional to the distance between the genes on the genetic map. The further apart they are, the higher the chance of crossing over.


Why other options are incorrect:

  • Length, width, and thickness of a chromosome have no direct bearing on the statistical probability of recombination between two specific mapped loci.

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.

Previous Question All Inheritance / Variation & Genetics MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App