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5 marksPatterns of Inheritance

CAPE Biology Unit 1 · 2011 · Paper 2 · Question 2(a)(iii)

A coloured rooster is mated with a white hen and produces all coloured offspring. Use the symbols F for the dominant gene for coloured feathers, f for the recessive allele for white feathers, A for the dominant gene which inhibits colour expression, and a for the recessive allele.

In the space provided, draw a genetic diagram to explain the cross.

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Other parts of this question

  1. 2(a)(i)State the term which describes the interaction of these two genes.[1 mark]
  2. 2(a)(ii)Define the terms 'allele' and 'dominant'.[2 marks]
  3. 2(b)(i)Based on the type of cross, deduce the expected ratio of the phenotypes.[1 mark]
  4. 2(b)(ii)formulate a possible null hypothesis for the Chi-square test.[1 mark]
  5. 2(b)(iii)State the formula for, and determine the number of degrees of freedom in the Chi-square test performed in (b)(ii), briefly explaining any terms used.[2 marks]
  6. 2(b)(iv)Use the calculated value of χ² (10.81) and the probabilities provided in Table 2 to find the probability of the results of the cross departing significantly by…[1 mark]
  7. 2(b)(v)What conclusion may be drawn from the probability found in (b)(iv)?[2 marks]

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