4. How might similarities and differences in genetic codes, or the proteins built as a result of these codes, be used to determine how closely related different species are?

Question

aaronq · Answer

You would use the similarity in the DNA sequences to align them, proposing that the more similar their sequence is the more closely-related in an evolutionary timeline.

As an example, suppose there are 5 organisms with genetic codes

(1) AAAAAA
(2) AAAAA$\sf \color{red}{C}$
(3) AAAA$\sf \color{red}{TC}$
(4) AAA$\sf \color{red}{CTC}$
(5) AA$\sf \color{red}{GCTC}$
(6) AA$\sf \color{green}C\color{red}{TCC}$

There is an order in which the changes in their sequences occurred, this order can be used to place them on a chart. 

|dw:1407028796810:dw|

We can see that (1) and (2) have more similarity than (2) and (5), and we can infer that they are more closely-related.