Question 1

Paper 2Easy5 marks

Researchers compare a short region of the same gene in three island lizard species. Figure 1 shows the aligned DNA base sequences.

DNA base sequence (same gene region)12345678Species PATGCCGTASpecies QATGCCATASpecies RTTGACATA
(a)

Determine the number of base differences between species P and species R in Figure 1.

[1]
(b)

Identify the pair of species with the most similar DNA sequences and state the number of base differences between them.

[2]
(c)

Explain why the similar DNA sequences of this pair provide evidence of common ancestry.

[2]

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