Genetic Comparisons


DNA comparisons

Steps involved in DNA comparison (DNA hybridisation)

Protein (Amino Acid) Comparisons




More reliable and accurate than mere physical resemblance in determining the genetic relationship between individuals and species, is of course a genetic comparison. This can be achieved either by directly analysing their DNA, or the proteins encoded by it.



DNA Comparisons


There is a correlation between the degree of relatedness between individuals/species, and the degree of similarity between their base sequences in DNA. For example, ACTGGAC and ACTGGAT are more similar than ACTGGAC and GCTGGAA. Hence, it may be deduced that the organism possessing the first sequence is more closely related to the second organism, than to the last organism.


One technique which enables scientists to carry out a DNA comparison is called DNA hybridisation. This involves the joining together of DNA sections from 2 species to be compared. These are the steps involved:


  1. DNA samples are collected, cut into smaller sections, then heated to 90 degrees.
  2. The heat denatures the DNA molecules by breaking the hydrogen bonds within; the strands of DNA separate.
  3. The separated strands from the two species are now put together and allowed to cool. 
  4. Some strands will join back with their original pair; others will join with strands from the other organism to form hybrid…..

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