Student Version


Name _______________________________         Date _______________

Mutations Activity:  Understanding the connection between changes in DNA and phenotype

GenScope File: Dragon

A mutation is an alteration in the DNA of an organism. When the DNA is changed, the action of the gene is changed and the resulting trait is different from the original.

Open GenScope using the Dragon file and click on the second button to produce a male dragon. Before you start messing around with the DNA, use the chromosome tool to bring up chromosome 1 which contains the horn gene. Click on the alleles on both chromosomes and refresh your memory about what happens to the organism with each combination of alleles.

1.       What are the rules for horns?

HH gives  ___________
Hh gives  ___________
hH gives  ___________
hh gives  ___________
2.       Now, do the same for wings. Write the rules for the inheritance of this trait, and test your answers.  Hint: To test patterns of inheritance, the alleles should be combines in various combinations - like and unlike. What are the rules for wings?

W W gives __________
W w gives __________
w W gives __________
w w gives __________

These are the "Rules" for inheritance of this trait in dragons. That was easy, wasn't it?

3.       Now let's make a mutation. Using the chromosome tool, open up the chromosome window if it isn't already open. Click on the DNA button. The cursor will turn into a rectangular magnifying glass when it is passed over the chromosome. Center it over the Color A gene on the X chromosome and click. A new window, the DNA window, will appear. If you add some of the four bases (Adenine, Thymine, Cytosine, Guanine) or delete some, then click on the Apply button, you will create a mutation. Go back to the chromosome window and check the menu for the Color A allele on the chromosomes. There should be a new allele listed, aw. Change both alleles to aw and watch what happens to your dragon in the organism window. Now determine what the rule of inheritance is for the albino gene and write it in the space below. Do the same for wings.

To do this, test the mutated gene in the same way that you tested the non-mutated genes: Change the menu for the gene on the chromosome so that you have 2 alleles the same, 2 unlike alleles, allele + mutated alleles and 2 mutated alleles. As you make the changes on the chromosomes, watch what happens to the dragon in the organism window.

What are the rules for Color A? A    A          ____________
A    a          ____________
a     A         ____________
a     a         ____________
A     aw     ____________
aw   A       ____________
a      aw     ____________
aw   a        ____________
aw   aw     ____________
A      -         ____________
a      -          ____________
aw   -          ____________
How about the rules for Wings?

W W gives     ____________
W w gives      ____________
w W gives      ____________
w w gives       ____________
W ww gives   ____________
w ww gives    ____________
ww ww gives ____________

4.      Now, using this information, can you come up with a general rule which would apply to the inheritance of other mutations? Write it in the space below.

5.       There are more mutations. See if you can find them. Write the various combinations of alleles and what the phenotype is for each in the table below:

a. firebreathing:
  F    F   _____________
F    f    _____________
F    -    _____________
f     f    _____________
f     -    _____________
F    ff   _____________
f     ff   _____________
ff    ff   _____________
ff    -    _____________
b. Horns:
  H h       _____________
H H      _____________
h h       _____________
H hh    _____________
h hh     _____________
hh hh  _____________
6.       Call your teacher over to see your tables.  Do these mutations follow the general rule you wrote?
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