Due to mutations, the sequence of two organisms with a common ancestor will become more dissimular over time.
One way to determine simularities in the DNA of different organisms is by using DNA hybridisation.
1 of 2
- DNA from 2 species is extracted and purified.
- DNA from one of the species is labelled using radioactive or fluorescent marker to it.
- Both sets of DNA is heated to seperate the strands (removing H bonds)
- The mixture is cooled to allow the strands to combine with strands with complementary organic bases.
- Some double strands will have one strand of each species (one labelled, one unlabelled.)
- These hybrid strands are seperated from the mixture.
- These are heated at different stages.
- If the species are closely related then the temperature taken to split the two strands is higher.
2 of 2