Download Analyzing Amino Acid Sequences to Determine

Molecular Evidence
Analyzing Amino Acid
Sequences to Determine
Evolutionary Relationships
Zach, Sally, and Sarah
Learning Target
1. Students will know examples of scientific
evidence that support the theory of evolution.
Evolution
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All organisms - common ancestor
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branched off, forming the phylogenetic tree.
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Scientists have used various methods to
research and prove this theory such as:
fossils, embryos, and molecular evidence.
Molecular Evidence
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Looking at the molecules of different
organisms have shown that:
o
o
o
o
o
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very similar: plasma membrane, RNA, & DNA
universal genetic code to produce proteins
500 genes common to all species
over time, some organisms have slowly
differentiated their DNA, forming new species
more similar DNA = more similar species
 example: humans & chimpanzees
most convincing evidence for evolution =
studying amino acid sequences
Amino Acid Sequences
Amino Acid Sequences
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Similar species to the human had similar
amino acid sequences.
Species that are not so similar to humans
have more different amino acid sequences.
Amino acid sequences are responsible for a
species features.
How/why - Change in DNA
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Evolution = change in a gene pool over time
o
As organisms adapted to their environments, their
genes mutated and/or recombined in different ways
during reproduction and were passed on to future
generations
o
Five Fingers of Evolution
 Small Population
 Non-random mating
 mutations
 gene flow
Humans-Chimps, Fish,
and Mice
Example #1
Humans - Horses
Portion of an amino acid chain
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o
#104-#116 of 146
Human
ARG-LEU-LEU-GLY-ASN-VAL-LEU-VAL-CYSVAL-LEU-ALA-HIS
Horse
ARG-LEU-LEU-GLY-ASN-VAL-LEU-ALA-LEU-
Example #2
Humans - Chimpanzees
Same exact portion of amino acid chain
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Human
ARG-LEU-LEU-GLY-ASN-VAL-LEU-VAL-CYSVAL-LEU-ALA-HIS
Chimp
ARG-LEU-LEU-GLY-ASN-VAL-LEU-VAL-CYS-