Name:  ______________________________                                    Date:  ____________


Identifying Disease Genes Worksheet


In this activity, you and your partner will be given a nucleotide sequence found in real human DNA that is associated with a genetic disease when mutated.  Your task is to compare the sequence you are given with known genes in the National Center for Biological Information (NCBI) website, using their Basic Logical Alignment Search Tool (BLAST) program. 



1)      Go to the NCBI website, found at, and click on the word “BLAST”, located on the dark blue bar near the top of the page. 

2)      Under the heading “Nucleotide”, click on the link for “Nucleotide-nucleotide BLAST”.  One person should read the nucleotide sequence found on the index card you were given (in groups of 3) while the other person CAREFULLY types in the exact nucleotide sequence in the large empty “Search box.

3)      When you or your partner finish typing, note in the space below any patterns you may have noticed about your sequence as it was being typed in. 




4)      Now click on the “BLAST!” button, and after it brings you to the next screen, click on the “Format!” button and wait for your results.

5)      On the webpage of your BLAST results, scroll down to the section with the horizontal colored lines, and carefully position your mouse on the “0” found below the word “Query”.  Now slowly move your mouse below to the start of the first colored line.  You should see the phrase “Mouse-over to show defline and scores, click to show alignments” in the white box change to indicate the name of the gene associated with the nucleotide sequence you typed in. 

6)      Slowly continue moving the mouse down each of the next 5 successive colored lines, taking note what appears in the white box.  What seems to be the name of your human gene?




7)      Close the “results of BLAST window”, going back to the “formatting BLAST” page.  Click on NCBI logo that appears in the top left hand corner of the page.  This should bring you back to the NCBI home page. 

8)      Now scroll down till you see the word “Education”, the 3rd-to-last orange heading on the left-hand bar of the page, and click on it. 

9)      Scroll down till you see the word “Genomes & Genetics” (2nd-to-last orange heading), and click on “Genes and disease”. 

10)  Enter the name of the gene or genetic disease associated with your nucleotide sequence in the search box at the top of the page and click “Go”.  Use the information returned with your search, as well as other resources on the NCBI website, to answer the questions on the other side of this page.


Answer the questions below, using information from your search and the NCBI website.  You will be sharing your responses with the rest of the class at the end of this activity.


1)      Name the genetic disease associated with the nucleotide sequence you were given.



2)      Identify the chromosome(s) on which this gene is most likely to be found.




3)      Describe the specific mutation(s) associated with this disease.








4)      Discuss the direct effects of such the mutation(s) you described in the previous question.








5)      Describe the effects and symptoms of this disease.








6)      Discuss the current treatment, if any, for the disease.








7)      Describe current research being done to learn more about this disease.


Sample Nucleotide Sequences for Known Human Genetic Disease Genes