1. Evidence of Evolution:
Comparative Biochemistry

2. Comparative Biochemistry

3. Comparative Biochemistry
1) All cells are made of the same basic types of compounds:
•Nucleotides (DNA)
•Proteins (strings of amino acids)
•Lipids
•Carbohydrates

4. Comparative Biochemistry

5. Comparative Biochemistry
1) When comparing DNA & protein structure there exists a
universal (across all species) genetic code for reproduction.
DNA is made-up of 4 universal nucleotides, commonly
referred to as A, T, C, G.

6. Comparative Biochemistry
1) Proteins are made-up from 20 universal amino
acids.

7. Comparative Biochemistry
The order of amino acids in a protein are
determined by the order of nucleotides in DNA.
(If there is a mutation in the DNA, the protein will
likely also change)
*Muscular dystrophy is a genetic
disease caused by mutation. It is
characterized by muscle weakness
and loss of muscle tissue.
Left: A healthy male. Right: A
male with muscular dystrophy.

8. Comparative Biochemistry
A point mutation is the altering of a DNA strand
with a single nucleotide. There are 3 kinds:
i) Insertion – A nucleotide is added and all others
are moved forward.
Ex.
Initial: ATA CGC AGA
Becomes: ATA CGT CAG A

9. Comparative Biochemistry
ii) Deletion – A nucleotide is removed and all
others are moved backward.
Ex.
Initial: ATA CGC AGA
Becomes: ATA CGA GA

10. Comparative Biochemistry
iii) Substitution – A nucleotide is switched with
another nucleotide.
Ex.
Initial: ATA CGC AGA
Becomes: ATA CGT AGA

11. Comparative Biochemistry
2) Comparing common genes:
A gene is a DNA sequence that is used to make a
protein.
By comparing gene or amino acid sequences, we
can see how closely related 2 species are.
cow CTATG GTTCC TAAGC ACAAG
deer CTATG GTTCC TAAGC ACGAA
whale CTATC CTTCC TAAGC ATAAA
hippo CTATC CTTCC TAAGC ATAAA
pig CCATT GTTCC CAAGC GTAAA
rat CCATC TTTCC TAAGC TCAAA

12. Comparative Biochemistry
Example: the protein hemoglobin (for gas exchange).
This chart compares short amino acid chains of
different animals.

13. Comparative Biochemistry
Example: the protein cytochrome c (for respiration)
contains between 100 and 104 amino acids.
This chart shows how many differences exist
between 2 species.

14. How is Comparative Biochemistry
Evidence of Evolution?