molecular comparisons between species

DNA comparisons

identifying the correlation between the relatedness of species and the degree of similarity between their base sequences in DNA

DNA hybridisation

joining together of DNA sections from 2 species to be compared

hybridisation step 1

collect DNA samples, cut them and heat to 90 degrees

hybridisation step 2

heat denatures the DNA molecules by breaking the hydrogen bonds within resulting in the DNA strands breaking

hybridisation step 3

separated strands from the 2 species are now put together and allowed to cool

hybridisation step 4

some strands join back with their original pair while others join to form hybrid DNA

temperature and DNA hybridisation

original bonding pairs joined bak at 87 degrees but hybrid DNA is formed at a lower temperature as fewer sequences are shared..the lower the temperature, the less genetically related they are

protein comparisons

compare the sequence of amino acids of 2 species and asses scale of similarities and differences..the fewer the differences, the closer the species are related