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5.1 Inheritance

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Question 3

In a species of sweet pea (Lathyrus odoratus), flower colour and pollen grain shape are determined by two genes located on the same autosome. A dihybrid plant heterozygous for both characteristics (PL/plPL/plPL/pl) is test-crossed with a double homozygous recessive plant (pl/plpl/plpl/pl).

The phenotypes of the resulting 1000 offspring are recorded as follows:

  • Purple flowers, long pollen: 415
  • Purple flowers, round pollen: 85
  • Red flowers, long pollen: 75
  • Red flowers, round pollen: 425

What is the recombination frequency between the locus for flower colour and the locus for pollen shape?

A

8.0%8.0\%8.0%

B

16.0%16.0\%16.0%

C

32.0%32.0\%32.0%

D

84.0%84.0\%84.0%

Markscheme

5.1 Inheritance Questions

  1. GCSE
  2. /Biology
  3. /5.1 Inheritance

97 exam-style questions on OCR GCSE Biology 5.1 Inheritance, covering 5.1.1 The genome, 5.1.2 Environment and phenotype, 5.1.3 Variants and mutations, 5.1.4 How genetic variants influence phenotype, 5.1.5 Asexual and sexual reproduction, 5.1.6 Haploid and diploid, 5.1.7 Meiotic cell division, 5.1.8 Single gene inheritance, 5.1.9 Predicting single gene crosses, 5.1.10 Sex determination, 5.1.11 Multiple gene inheritance, and 5.1.12 Development of our understanding of genetics. Each one has a worked solution and a mark scheme showing where the marks go.

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