Assessing relatedness with genetic evidence
During evolution species undergo changes within their DNA base sequences, these accumulate until the organisms are so different that they're considred to be different species. More closely related species show more similarity in their DNA base sequences than those more distantly related. DNA analysis has confirmed evolutionary relationships, correcting mistakes made in classification bases on physical characteristics.
This involves comparing the DNA base sequences of two species. To work out how closely related two species of primates are, DNA from both is extracted, separated and cut into fragments. The fragments from the two species are mixed, where they have complementary base sequences they hybridise together. This method has shown chimpanzees and humans have at least 95% of DNA in common, humans and rhesus monkeys have about 93% of their DNA in common.
Amino acid sequences
The sequence of amino acids in proteins is determined by the DNA base sequence. The degree of similarity in the amino acid sequence of the same protein in two different species reflects how closely related they are.
The proteins of different species can be compared using immunological…