BIOL 103 Home

Mutant 5. Dr. Xavier: DNA BLAST

Facts about Genomes. See 20 Facts about the Human Genome

  • There are 100 trillion (1012) cells in your body. Each cell contains DNA double helix totalling three billion (3 x 109) base pairs.
  • If unwound and linked together, the strands of DNA in one cell would stretch almost six feet but would be only 50 trillionths of an inch wide.
  • It would take about 9.5 years to read out loud (without stopping) the 3 billion bases in a person's genome sequence, if you read at a rate of 10 bases per second.
  • If all the DNA in your body was put end to end, it would reach to the sun and back over 600 times (100 trillion times six feet divided by 92 million miles).
  • Human DNA is 98 percent identical to chimpanzee DNA. Human DNA is 30% identical to E. coli DNA.
  • The average amount of genetic difference between any two humans is 0.2 %, or one in 500 bases. Chimpanzees differ by 0.8 %.

Useful Sites

  • NCBI (National Center for Biotechnology Information)
  • OMIM (Online Mendelian Inheritance in Man)
  • BLAST DNA-DNA comparison
  • Webcutter Restriction enzyme mapping
  • Human Genome

 

Honor Pledge. I affirm that I have completed this assignment on my own, aside from the professor and the MSSC. Any outside source of information must be credited.
Signature (typed): ________________________________

1. Dr. Xavier's challenge: "We Mutants are an entirely different species from you, since 3 million base pairs of our DNA differ 100% from yours."
What do you say?

2. As a doctor, you are investigating a patient with a Mutant immune system that mysteriously resists AIDS and other diseases. From the patient you identify this small piece of DNA:

gcatctgttt aaagtagatt agatctttta agcccatcaa ttatagaaag ccaaatcaaa
atatgttgat gaaaaatagc aaccttttta tctccccttc acatgcatca agttattgac
aaactctccc ttcactccga cccttcctta tgtatattta aaagaaagcc tcagagaatt
gctgattctt gagtttagtg atctgaacag aaataccaaa attatttcag aaatgtacaa
ctttttacct agtacaaggc aacatatagg ttgtaaatgt gtttaaaaca ggtctttgtc
ttgctatggg gagaaaagac atgaatatga ttagtaaaga aatgacactt ttcatgtgtg

 

Use the appropriate program (from list above) to determine:
(A) What gene is it?
(B) What protein does it make?
(C) What is the function of this protein?

(D) What is the Mutation? Check the sequence alignments below. Compare Query sequence (yours) with Subject (the "normal" gene in the database.)
(E) Why does the Mutant resist AIDS disease?

 

3. Paste the DNA gene sequence (from above) into Webcutter. Generate a restriction enzyme map showing all the enzyme cut sites in the sequence.

Name two different restriction enzymes that cut specific sites in this DNA.

 

4. Explain how you can use PCR to make many copies of the DNA above.

Write a pair of two 20-base primer sequences that could be used to amplify (make copies of) this entire piece. Remember that the above sequence shows only one strand of the gene; there is always a second complementary strand present.

 

5. How could you clone an E. coli strain that would express the entire Mutant protein? What additional kind of DNA would have to be used, and how? What kinds of enzymes would be needed?

 

6. Why is it easier to clone an E. coli strain than to clone a dinosaur? (Explain several reasons).

 

7. Suppose you want to genetically engineer a person to resist AIDS disease. In order to insert the Mutant resistance gene into human DNA, you need to cut human DNA with a restriction enzyme. For a restriction enzyme of sequence CAATTG, about how many cut sites would you expect in the entire genome? (Note: Use your calculator for a simple calculation; no database needed.)

 

8. What might The President's Council on Bioethics have to say about the experiment in problem 7? Why might they be concerned about this experiment?