Igcse Model Questions Vol1 2023 Biology Question 22

Practice objective / multiple choice question 22 from the 2023 Igcse Model Questions Vol1 Biology examination.

Igcse Model Questions Vol1 2023 Biology Objective / Multiple Choice Medium Difficulty
Question 22 IGCSE_MODEL_QUESTIONS_VOL1 • 2023 • BIOLOGY • objective

A plant heterozygous for two linked genes A and B (genotype AaBb) in coupling phase (AB/ab) is test‑crossed with a plant homozygous recessive (aabb). Among 2000 offspring the following phenotypes are recorded: 820 tall green, 780 short yellow, 250 tall yellow, and 150 short green.\n\n(a) Calculate the recombination frequency between the two genes and give the map distance in centiMorgans.\n(b) If the recombination frequency were 12 %, what proportion of the offspring would be expected to be tall yellow?

Answer Options

A. (a) 30 % recombination frequency (30 cM); (b) 12 % of the offspring would be tall yellow.
B. (a) 25 % recombination frequency (25 cM); (b) 8 % of the offspring would be tall yellow.
Correct Answer C. (a) 20 % recombination frequency (20 cM); (b) 6 % of the offspring would be tall yellow.
D. (a) 15 % recombination frequency (15 cM); (b) 5 % of the offspring would be tall yellow.
Correct Answer
C
Correct Option:
(a) 20 % recombination frequency (20 cM); (b) 6 % of the offspring would be tall yellow.

About This Question

This is Igcse Model Questions Vol1 2023 Biology Question 22. It is one of the objective questions from the 2023 Igcse Model Questions Vol1 Biology examination.

Difficulty level: Medium .

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