DH measures the degree of genetic similarity between pools of DNA sequences. It is used to determine the genetic distance between two species.
Technique
- DNA sample from 2 different species are heated separately to a boiling point in order to separate strands
- samples mixed + allowed to cool
- separate strands from 2 sample begin to hybridised, (re-bind), these are identified as they 50% labelled
- hybrid strands are separated out + temp is increases in stages
- if 2 species are closely related, they share complementary bases, hydrogen bonds link them together
- more H bonds, stronger hybrid strand will be
- stronger hybrid strand, higher temp needed to separate into 2 single strands, high temp at which hybrid strand spilts, more closely 2 species are related
- lower temp at which hybrid spilts, more distantly species are related.
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