Genotype Vs. Phenotype
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 only, which organisms 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 bases (each letter) are the same as 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 Genotype # of genetic bases in common with
Tunicate
42 Tunicate
Yellowfin
Tuna
Wallaby
Green Sea
Turtle
Coqui Frog
Hoary Bat
Human
GTAAGCCGTTTAGCGTTAACGTCCGTAGCTAAGGTCCGTAGC
GTAAAATTTTTAGCGTTAATTCATGTAGCTAAGGTCCGTAGC
GTTTAATTAAAAGCGTTCCTTCATGTAGCTTCCACGCGGCGC
GTATAATTAAAAGCGTTAATTCATGTAGCTTCCGTCCGGCGC
GTTTAATTAAAAGATTTCCTTCATGTAGCTTCCACGCGGCGC
GTTTAATTAAAAGATTTCCTTCATGTGGCTTCCACGCGGCGC
GTAAAATTAAAAGCGTTAATTCATGTAGCTAAGGTCCGGCGC
3. Write the organisms in order from most related to least related to the Tunicate.
33
18
4. Which other organisms show a close relationship. Give 2 examples, and EXPLAIN HOW you know they are closely related.
5. Did your first prediction (based on phenotype alone) match what the genetic data concludes? EXPLAIN.
6. So, what is the relationship between the phenotype and genotype?
7. HOMEWORK: Scientists debate the positive and negative aspects of using phenotype (morphological) or genotype (molecular) data and characteristics to analyze relationships between organisms. What do you think are the pros and cons of each method?
Create a chart in your notebook (it can be on page 6 under where you tape this note guide) that gives at least 2 pros and 2 cons for each method!
Method
Phenotype
Genotype
Pros Cons