Suggest why the cytochrome b gene is used to measure changes in DNA sequences in closely related species.

1. Cytochrome b is a homologous gene meaning that it is conserved in all the species being compared 
2. was found in their common ancestor; forms the basis of comparison 
3. Yet there are sufficient differences in the DNA of cytochrome b for scientists to distinguish between closely related species 
4. It is found in the mitochondria and hence do not undergo recombination and any mutation accumulates at a regular rate in the maternal line --> can be used for molecular clock