=DNA Hybridisation= [image:http://i.imgur.com/plBo98K.png] DNA Hybridisation is a technique in which DNA is heated, breaking the weak hydrogen bonds that hold the two strands together. The hydrogen bonds holding the two strands together are weaker than the covalent bonds between the sugar, phosphate and base groups. Thus the two stands can be separated without damaging the DNA sequence. When the DNA is allowed to cool, complimentary sequences can bond back together again (called annealing). This technique can be used to compare the DNA sequences of different species. DNA from each species is cut into small segments and heated, causing the DNA strands to separate. As the solution is allowed to cool, the two species’ DNA strands interact. The match between the two strands is not perfect as there are some genetic differences. The more imperfect the match, the weaker the bond between the two strands. These weak bonds can be broken with just a little heat, while closer matches require more heat to separate the strands again. This technique can be used to quickly assess how closely two species are related to one-another.
Credit: Ben Himme