Credit Sprint / Practice problems / Recombination frequency and map distance

Recombination frequency and map distance practice problems

Biology Unit 5. Try each one, then open the worked solution. The Credit Sprint app generates unlimited new versions with fresh numbers.

Problem 1.

In a test cross, 173 of 1000 offspring are recombinants. What is the distance between the genes in map units?

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Recombination frequency = 173 ÷ 1000 = 0.173 → 17.3 map units.

Problem 2.

In a test cross, 13 of 200 offspring are recombinants. What is the distance between the genes in map units?

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Recombination frequency = 13 ÷ 200 = 0.065 → 6.5 map units.

Problem 3.

In a test cross, 37 of 200 offspring are recombinants. What is the distance between the genes in map units?

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Recombination frequency = 37 ÷ 200 = 0.185 → 18.5 map units.

Problem 4.

In a test cross, 17 of 400 offspring are recombinants. What is the distance between the genes in map units?

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Recombination frequency = 17 ÷ 400 = 0.043 → 4.25 map units.

Problem 5.

In a test cross, 295 of 1000 offspring are recombinants. What is the distance between the genes in map units?

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Recombination frequency = 295 ÷ 1000 = 0.295 → 29.5 map units.

Problem 6.

In a test cross, 99 of 400 offspring are recombinants. What is the distance between the genes in map units?

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Recombination frequency = 99 ÷ 400 = 0.248 → 24.75 map units.