Comparison of Major Prion
Protein Precursor in Primate species
Trees are a way of organizing different species in an order that shows their relationship. The tree here is a rooted tree. It begins on the left, this first part is a common, unknown, ancestor which all of these different primate species evolved from. Areas where the tree branches off show specific mutations that occur to bring about the development of different, unique species.
Rooted Tree of Primate Species
You can see many relationships based on trees, the difficulty is that we can only view the differences in these animals in relation to their similarities or differences in one protein which they share. They may look to have very different branch systems and relationships if a different protein is chosen. The protein used to compare on this tree is the major prion protein procursor.
As you can see this first tree shows that the original ancestor split off into two distinct groups rather early on. These two groups are most likely Old world monkeys (Catarrhini) and New world monkeys (Platyrrhini). One interesting circumstance is that the Common Squirrel Monkey is a New World Monkey, but when the tree branches off into two different sections it remains with the Old World Primates like Chimpanzees and humans. This shows that according to this one protein the Squirrel monkey is more related to humans and other Old World Monkeys than other New World Monkeys. So, this one protein could not be used by itself to decide which suborder a primate belongs to because there are exceptions. But, it is succesful in showing basically how alike organisms are.
The tools in the Biology Workbench allow you to access the databases that contain information about different proteins. This web site is accessible through the link http://workbench.sdsc.edu. The workbench allows you to pull up proteins of any animal researched and placed on the database. If anyone has studied the makeup of an animals protein and wants to make it accessible to the public they will place it online so it can be used to compare and make trees from.
Comparing Chimp and Human Amino Acid Sequences
Another tool contained in the workbench allows you to compare the sequences of different proteins. On the next page you will see the sequence of a human for the major prion protein precursor compared with the same sequence in a chimpanzee.
HGGGWGQPHGGGWGQPHGGGWGQPHGGGWGQGGGTHSQWNKPSKPKTNMKHMAGAAAAG HGGGWGQPHGGGWGQPHGGGWGQPHGGGWGQGGGTHSQWNKPSKPKTNMKHMAGAAAAG
AVVGGLGGYMLGSAMSRPIIHFGSDYEDRYYRENMHRYPNQVYYRPMDEYSNQNNFVHDCV AVVGGLGGYMLGSAMSRPIIHFGSDYEDRYYRENMHRYPNQVYYRPMDQYSSQNNFVHDCV
NITIKQHTVTTTTKGENFTETDVKMMERVVEQMCITQYERESQAYYQRGSSMVLFSSPPV
NITIKQHTVTTTTKGENFTETDVKMMERVVEQMCITQYERESQAYYQRGSSMVLFSSPPV
ILLISFLIFLIVG
ILLISFLIFLIVG
The top line of each row is the human sequence. The second line is a chimpanzee sequence. As you can see the two are very related, only having two different nucleotides. Compared to another animal the human would most likely differ greatly. This could be used to prove the idea that chimpanzees really are our closest living relatives. It is believed that chimpanzees share 98% of our genetic makeup. So comparing many protein and gene sequences we should be able to see the many similarities.
By: Heather Hassel
