Bio H – Genetics
How to Build a Dragon
Background:
In class we examined how Mendel came up with his Laws of Inheritance through the analysis of
patterns in pea plant reproduction. While exciting in a sort of vegetable-y goodness kind of way, there
are definitely more exciting test subjects we could use to better understand patterns of inheritance. In
this exercise we are going to be presenting a hypothetical offspring of the mythical species Drago
dragonians.
Procedure:
1.
Choose a partner. You and your dragon spouse will share the grade for this lab. The lab must be
completed by the end of the period.
2.
Each person must pick up five Popsicle sticks from the front of the classroom -- one of each color of
autosome, and one sex chromosome. One partner should have a white chromosome with a Y on
the back. This person is the father. Each side of a stick represents a chromosome, and the
two sides together represent a pair of homologous chromosomes. The letters represent the
alleles found on each chromosome.
3.
Once you have a partner, it is time to figure out the genotypes of the parents. Each partner should
examine their chromosomes and write their genotypes down in their column on the data sheet.
Your genotype is the combination of alleles you have on the front AND back of each
chromosomes. Remember the "Dad" dragon only has one set of X alleles and a Y allele.
4.
After you've determined your genotypes, you will simulate reproduction in dragons. Each parent
should flip their chromosomes (one at a time) to see which of their two alleles they are passing on
in a gamete. The side of the stick that is up represents the chromosome that is passed on to the
baby through the egg cell or sperm cell.
5.
After each drop, record the face up alleles in the appropriate column in the data chart. Together
these two alleles represent the genotype of your baby dragon.
6.
The Chart of Characteristics provides you with all the necessary alleles that exist for each trait AND
their inheritance pattern. Be sure to pay attention to the right hand column when determining your
dragon's phenotypes.
7.
After you have completed your data chart and the discussion questions, if time remains, you may
draw a picture of your new little bundle of fire-breathing joy. You don't have to be a fantastic artist,
but your baby's traits should reflect the phenotypes determined by his/her genes. BUT, you must
complete the graded portion
Bio H – Genetics
Chart of Characteristics
Chromosome
Gene
Allele 1
Green Autosome
Chin spike
A = no chin spike
a = has a chin spike
Complete dominance
Nose spike
B = nose spike
b = no nose spike
Complete dominance
Horn shape
C = straight horns
c = curved horns
Complete dominance
Ear hole
D = no visible ear hole
d = visible ear hole
Complete dominance
Eye position
e = one eye in the
middle of forehead
f = short neck
Co-dominance
Length of neck
E = two eye on side of
forehead
F = Long neck
Back Hump
G = no back hump
g = back hump
Complete dominance
Back spikes
H = no back spikes
h = back spikes
Complete dominance
Tail length
I = long tail
i = short tail
Foot shape
J = flat feet
j = arched feet
Incomplete
dominance
Complete dominance
Eye color
K = Red eyes
k = yellow eyes
Complete dominance
Neck spots
L = spots on neck
l = no spots on neck
Complete dominance
Wings
M= wings
m = No wings
Complete dominance
Fangs
N = No fangs
n = Long fangs
Back spots
O = spots on back
o = no spots on back
Incomplete
dominance
Complete dominance
Thigh spots
P = no spots on thigh
p = spots on thigh
Complete dominance
Body color
Q = green body
q = purple body
Complete dominance
Head comb
R = small comb on head
r = large comb on head
Complete dominance
Body spots
S = Red spots
s = Yellow spots
Co-dominance
Joint spikes
T = Knee spike
t = Elbow spike
Co-dominance
Thigh shape
U = regular thigh
u = pointed thigh
Complete dominance
Number of
toes
Chest plate
V = four toes
v = three toes
Complete dominance
W = no chest plate
w = chest plate
Complete dominance
Tail spike
X = no tail spike
x = tail spike
Complete dominance
Body odor
Z = stinky
z = odorless
Complete dominance
-
Complete dominance
Red Autosome
Pink Autosome
Yellow Autosome
X chromosome
(white)
Y chromosome
(white)
Fire breathing + = non-fire breather
ability
Determines male sex only
Allele 2
Fire breather
Inheritance
pattern
Complete dominance
Bio H – Genetics
Names ________________
_________________
Green Autosomes
Genotypes of
Alleles in
Mom
Dad
Egg
Sperm
Phenotype of Baby
Red Autosomes
Genotypes of
Mom
Dad
Alleles in
Egg
Sperm
Phenotype of Baby
Pink Autosomes
Genotypes of
Mom
Dad
Alleles in
Egg
Sperm
Phenotype of Baby
Yellow Autosomes
Genotypes of
Alleles in
Mom
Dad
Egg
Sperm
Phenotype of Baby
Sex Chromosomes (White X White Y)
Genotypes of
Alleles in
Mom
Dad
Egg
Sperm
Phenotype of Baby
Bio H – Genetics
Discussion Questions –
1. In what way was Mendel’s Law of Segregation demonstrated in this lab?
2. In what was Mendel’s Law of Independent Assortment demonstrated in this lab?
3. While genes on different chromosomes, assort independently, do genes located on the same
chromosome always separate independently? In other words, is the inheritance of the allele for chin
spikes completely independent of the inheritance of the allele for ear holes? Can it be? Explain.
4. What is the sex of your baby dragon? Who decides the gender of the offspring, the mother or father?
5. In the world of dragons, males are much more likely to get chest plates and tail spikes. What is the
reason for this phenomenon?
Punnett Squares: work these last two out on a separate piece of paper and attach it to your lab.
6. If two medium tailed dragons lay 200 eggs during their happy dragon marital years. How many of
their offspring would you expect to be tail-less? Show your work.
7. Considering your genotypes (you being mom and dad dragon) for body spots and tail length what was
the chance of you producing the child that you did. (yes this requires a Punnett square. Work it out
on a separate piece of paper and attach it to your lab.