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Dennis Drayna, Ph.D.

Section on Systems Biology of Communication Disorders
Laboratory of Molecular Genetics

5 Research Court, Room 2B44
Rockville, MD 20850
Phone: (301) 402-4930
Fax: (301) 480-8019

Ph.D., Harvard University, 1981

Research Statement

The Section on Systems Biology of Communication Disorders is focused on identifying genetic variation in the molecular components of human communication systems. Our primary tools are genetic linkage and positional cloning studies, used to identify genes responsible for communication disorders in humans, including disorders of auditory pitch recognition, deficits in the human sense of bitter taste, and the speech disorder of stuttering.

Recent Accomplishments

Bitter taste receptor genes: View primer sequences for specific amplification of each human bitter taste receptor (Microsoft Excel version). For further details, see Human Mutation (U.-K. Kim, S. Wooding, D. Ricci, L. B. Jorde, D. Drayna; in press).

Pitch perception: We've developed a standardized test for deficits in pitch recognition, using musical melodic pitch as the test paradigm. Using this test we have demonstrated that approximately 5% of the U.S. population show reproducible deficits in pitch perception. We have completed a study of over 250 pairs of twins with this test, and have shown that the heritability of deficits in pitch recognition is extremely high, with little effect of environmental experience. Details of our test can be seen here.

Chemosensory deficits: We have focused on deficits in the sense of bitter taste, using the inability to taste phenylthiocarbamide (PTC) as our experimental system. This is the most common sensory deficit in humans, affecting approximately one billion individuals worldwide. Using genetic methods, we have identified the gene responsible for this deficit. This gene encodes a member of the TAS2R bitter taste receptor family, expressed in taste cells on the tongue. The taster form of the gene product differs at three places from the non-taster form. These two forms are of ancient origin and diverged before modern humans migrated out of Africa. Biochemical, anthropological, and molecular structural studies of the different forms of this receptor are currently under way to help provide information about basic mechanisms of our sense of bitter taste.

Stuttering: We have assembled and characterized a collection of over 200 families with familial stuttering from North America. In these families, we have demonstrated that unlike the general stuttering population, where males outnumber females by about 4 to 1, familial stuttering shows a male to female ratio of 1.6. In a genetic linkage study, we identified a location on chromosome 18 that appears to be important as a determinant of this disorder. We are currently performing additional genetic studies in a series of 40 highly inbred families of Pakistani origin, and in a single large family from equatorial West Africa in which stuttering occurs in a simple inheritance pattern.

Lab Personnel

Un-kyung Kim, Ph.D. (Send e-mail)
Naveeda Riaz, Ph.D. (Send e-mail)
Bailey Levis, B.S. (Send e-mail)

Selected Publications


Ear and broken notes
Got a tin ear?
Test your sense of pitch on the Distorted Tunes Test

Bitter taste receptor genes

Primer sequences for specific amplification of human bitter taste receptors (Microsoft Excel version)

Related Topics:
NIDCD’s Dr. Dennis Drayna discusses stuttering research on ABC’s "Primetime: Medical Mysteries" (1/07)

National Institute on Deafness and Other Communication Disorders. Celebrating 20 years of research: 1988 to 2008