Genotype Vs. Phenotype Analysis
Directions: Scientists use both the phenotype (morphological data about an organisms body structure) and genotype (molecular
data about an organisms DNA sequences) to build evolutionary relationships between organisms. 1) You will first compare the
pictures of each organism and try to determine how closely related they are based on their phenotypes alone. 2) Then, you will
compare the DNA sequences from each organism to try and determine how closely related they are based on their genotypes.
Tunicate
Yellowfin Tuna
Wallaby
Green Sea Turtle
Coqui Frog
Hoary Bat
Human
1. Based on the images & any background knowledge you may have, which organisms do you feel are the most closely related?
EXPLAIN WHY you feel that way.
2. Examine the DNA sequence of each organism and count how many of the gene bases (each letter) are the same as the Tunicate.
(So, you are comparing all of them back to the Tunicate!) The first 3 are done for you, so fill in the rest of the column. It might help
to highlight common DNA sequences in different colors!
Organism
Tunicate
GTAAGCCGTTTAGCGTTAACGTCCGTAGCTAAGGTCCGTAGC
# of genetic bases in
common with
Tunicate
42 total gene bases
Yellowfin
Tuna
GTAAAATTTTTAGCGTTAATTCATGTAGCTAAGGTCCGTAGC
33 in common
GTTTAATTAAAAGCGTTCCTTCATGTAGCTTCCACGCGGCGC
18 in common
Wallaby
Green Sea
Turtle
Genotype
GTATAATTAAAAGCGTTAATTCATGTAGCTTCCGTCCGGCGC
GTAAAATTAAAAGCGTTAATTCATGTAGCTAAGGTCCGGCGC
Coqui Frog
GTTTAATTAAAAGATTTCCTTCATGTAGCTTCCACGCGGCGC
Hoary Bat
GTTTAATTAAAAGATTTCCTTCATGTGGCTTCCACGCGGCGC
Human
3. Write the organisms in order from most related to least related to the Tunicate.
4. Give one example of two other organisms that show a close relationship. How do you know they are closely related?
5. What are the pros and cons of using only phenotype or genotype to determine how closely related to organisms are? Why is it
best to use both?