Protein Evolution (amino acid sequence changes)
Backward translation - Hemoglobin is a protein that allows blood cells to carry oxygen to all the tissues of the body. Decode the mRNA transcript using the amino acid sequence for “human”. When there is more than one codon for an amino acid, write them all down….there could be up to six codons for a single amino acid. See the chart on the back for amino acid abbreviations.
ACG
ACA
ACU
ACC
threonine - - - - - - - - - -
87 88 89 90 91 92 93 94 95 96
- - - - - - - - - - -
97 98 99 100 101 102 103 104 105 106
- - - - - - - - - - -
107 108 109 110 111 112 113 114 115 116
Compare each of the animal combinations listed below. Determine the total number of amino acid variations. Then choose a unique variation pair(s) and use them to fill out the charts. For each, write the different amino acids and their possible codons. Then compare the number of base code changes that exist between the two amino acids. The difference was most likely caused by a point or inversion mutation…highlight/circle the codons that are the most likely candidates for the mutation and indicate which type of mutation you think occurred. Then show one possibility of how this change took place.
Human / Gorilla (total # of differences____) aa# human possible codons gorilla possible codons
Human/ Monkey (total # of differences____) aa# human possible codons monkey possible codons mutation possibilities-
Human/Horse(total # of differences____) aa# human possible codons horse possible codons
mutation possibilities -
Gorilla/Monkey (total # of differences____) aa# gorilla possible codons monkey possible codons mutation posibilities-
Gorilla/Horse (total # of differences____) aa# gorilla possible codons horse possible codons
mutation possibilities - aa#
Monkey/Horse (total # of differences____) monkey possible codons horse possible codons mutation possibilities - mutation possibilities-
Using your data, enter the animals in the ancestral tree below. Connections represent shared common ancestry. The more similarities in the protein’s amino acid sequence, the more closely related the organisms are. Vertical travel on the tree indicates time of divergence.
________
_________ _________ ________

Cytochrome C is a protein that is important for cellular respiration(metabolism) in mitochondria. Use the table below to collect your data on amino acid differences between all of the animals. Since we are only looking at one protein, there may be some situations where our pattern of more differences = less related and less differences = more related is skewed. In a real world situation, evolutionary biologists would compare larger amounts of DNA…all the way up to the whole genome. horse tuna chick frog human shark turtle monk rabbit horse tuna chick frog human shark turtle monk rabbit
Phyologenetic tree of common ancestry.
Construct your own tree of descent using the data you gathered. The basic idea is to place animals with more differences further from each other and those with less closer. You should make a rough draft before you write on this paper. Place all nine animals in your tree. Remember, since we are only looking at a small segment of one protein, there are a number of interpretations that could be displayed in your tree…in other words, answers will vary slightly.