0
Get Alert
Please Wait... Processing your request... Please Wait.
You must sign in to sign-up for alerts.

Please confirm that your email address is correct, so you can successfully receive this alert.

1
Images In Neuroscience   |    
The Human Genome SequenceThe Human Genome II: Sources of Genetic Variation
Carol A. Tamminga, M.D.
Am J Psychiatry 2001;158:691-691. doi:10.1176/appi.ajp.158.5.691

The simple property of base pairing is central to a rapidly evolving DNA technology with which researchers can now directly examine the genetic structure of individual human beings to search for sequence variations that are correlated with specific disease states. The ultimate goal of this research is to find the gene variants that cause or influence vulnerability to disease. Techniques such as Southern blot analysis and restriction fragment length polymorphism analysis have been used to detect variations in individual DNA. Now a more efficient technique, polymerase chain reaction (PCR), is universally used. PCR copies specific regions of human DNA using a temperature-activated enzyme (Taq polymerase) and nucleotide primers matched to the DNA region of interest. After DNA amplification with PCR, the sequence-amplified products can be analyzed for single-base variations or polymorphisms (from the Greek, meaning "multiple forms"). All people carry innocuous sequence variations in their DNA; these variations occur at a rate of approximately one for every 1,000 bases. One of these sequence variations could be associated with risk for a disease. Techniques for identifying the millions of variations of single nucleotides (called single nucleotide polymorphisms [SNPs]) in human DNA are being used to catalogue the extensive variation in the human genome. The ultimate goal of this effort by the Human Genome Project, involving an international network of cooperating scientists, is to identify, localize, and determine the sequence of all genes and their rates of variation.

Address reprint requests to Dr. Tamminga, Maryland Psychiatric Research Center, University of Maryland, P.O. Box 21247, Baltimore, MD 21228, ctamming@mprc.umaryland.edu (e-mail). The image is courtesy of the Department of Energy Human Genome Program, http://www.ornl.gov/hgmis.

 
Anchor for JumpAnchor for JumpAnchor for Jump

Figure. The image shows how DNA sequence variation in a gene can change the protein produced by the genetic code. The nucleotide triplet codon at position 1 in the gene depicted is different in person 1 and person 2, but the codon difference does not change the amino acid sequence. In person 3, the nucleotide triplet codon at position 2 is different from that in person 1 and person 2, and the codon change results in production of a different amino acid at position 2 in person 3.

Figure. The image shows how DNA sequence variation in a gene can change the protein produced by the genetic code. The nucleotide triplet codon at position 1 in the gene depicted is different in person 1 and person 2, but the codon difference does not change the amino acid sequence. In person 3, the nucleotide triplet codon at position 2 is different from that in person 1 and person 2, and the codon change results in production of a different amino acid at position 2 in person 3.

+

References

+
+

CME Activity

There is currently no quiz available for this resource. Please click here to go to the CME page to find another.
Submit a Comments
Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
Comments are moderated and will appear on the site at the discertion of APA editorial staff.

* = Required Field
(if multiple authors, separate names by comma)
Example: John Doe



Related Content
Books
The American Psychiatric Publishing Textbook of Geriatric Psychiatry, 4th Edition > Chapter 6.  >
The American Psychiatric Publishing Textbook of Geriatric Psychiatry, 4th Edition > Chapter 6.  >
The American Psychiatric Publishing Textbook of Geriatric Psychiatry, 4th Edition > Chapter 6.  >
The American Psychiatric Publishing Textbook of Geriatric Psychiatry, 4th Edition > Chapter 6.  >
The American Psychiatric Publishing Textbook of Psychopharmacology, 4th Edition > Chapter 3.  >
Topic Collections
Psychiatric News
PubMed Articles