3.20 Human Genome

What is your genetic code?

The sequence of letters above represents bases in someone's DNA. It is now possible to find out a person's entire genetic code by determining all the bases in his or her DNA. What might be the benefits?

Human Genome Project

A person’s genome is all of his or her genetic information. In other words, the human genome is all the information that makes us human. And unless you have an identical twin, your genome is unique. No one else has a genome just like yours, though all our genomes are similar.

The Human Genome Project (Figure below) was an international effort to sequence all 3 billion bases that make up our DNA and to identify within this code more than 20,000 human genes. Scientists also completed a chromosome map, identifying where the genes are located on each of the chromosomes. The Human Genome Project was completed in 2003. Though the Human Genome Project is finished, analysis of the data will continue for many years. To say the Human Genome Project has been beneficial to mankind would be an understatement.

To complete the Human Genome Project, all 23 pairs of chromosomes in the human body were sequenced. Each chromosome contains thousands of genes. This is a karyotype, a visual representation of an individual’s chromosomes lined up by size.

Exciting applications of the Human Genome Project include the following:

• The genetic basis for many diseases can be more easily determined. Now there are tests for over 1,000 genetic disorders.
• The technologies developed during this effort, and since the completion of this project, will reduce the cost of sequencing a person's genome. This may eventually allow many people to sequence their individual genome.
• Analysis of your own genome could determine if you are at risk for specific diseases.
• Knowing you might be genetically prone to a certain disease would allow you to make preventive lifestyle changes or have medical screenings.

The video Our Molecular Selves discusses the human genome, and is available at http://www.genome.gov/25520211 or http://www.youtube.com/watch?v=_EK3g6px7Ik. Genome, Unlocking Life's Code is the Smithsonian National Museum of Natural History's exhibit on the human genome. See http://unlockinglifescode.org to visit the exhibit.

Summary

• The Human Genome Project involved an international effort to sequence all 3 billion bases that make up our DNA and to identify within this code more than 20,000 human genes.
• Analysis of your own genome could determine if you are at risk for specific diseases.

Explore More

Use the resources below to answer the questions that follow.

Explore More I

• PCR Virtual Lab at http://learn.genetics.utah.edu/content/labs/pcr/

1. How many copies of a DNA sequence can be made in a matter of hours using PCR?
2. About how much DNA do you need to start the PCR process?
3. Can you use the same primers for every DNA sequence you want to investigate? Why or why not?
4. How many "ingredients" go into your PCR tube? What are they?
5. What happens at 95°C during the PCR process?
6. What happens at 72°C during the PCR process?

Explore More II

• Personal Genome Project at http://www.personalgenomes.org

1. What is the goal of the personal genome project?
2. What information are they seeking besides a person's genome?
3. Why participate in the PGP?

Review

1. What is a person's genome?
2. Describe the Human Genome Project.
3. Would you want to know your own genome? Why or why not?