Dennis Drayna, Ph.D.
Chief Section on Systems Biology of Communication Disorders Laboratory of Molecular Genetics
NIDCD/NIH 5 Research Court, Room 2B44 Rockville, MD 20850 Phone: (301) 402-4930 Fax: (301) 480-8019 E-mail: drayna@nidcd.nih.gov
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
- Prodi DA, Drayna D, Forabosco P, Palmas MA, Maestrale GB, Piras D, Pirastu M, Angius A. Bitter taste study in a sardinian genetic isolate supports the association of phenylthiocarbamide sensitivity to the TAS2R38 bitter receptor gene. Chemical Senses 29(8):697–702, 2004.
- Kim UK, Breslin PA, Reed D, Drayna D. Genetics of human taste perception. Journal of Dental Research 83(6):448–53, 2004.
- Wooding S, Kim UK, Bamshad MJ, Larsen J, Jorde LB, Drayna D. Natural selection and molecular evolution in PTC, a bitter-taste receptor gene. American Journal of Human Genetics 74(4):637–46, 2004.
- Shugart YY, Mundorff J, Kilshaw J, Doheny K, Doan B, Wanyee J, Green ED, Drayna D. Results of a genome-wide linkage scan for stuttering. American Journal of Medical Genetics 124A(2):133–5, 2004.
- Drayna D, Kim UK, Coon H, Jorgenson E, Risch N, Leppert M. A model system for identifying genes underlying complex traits. Cold Spring Harbor Symposia on Quantitative Biology 68:365–71, 2003.
- Puls I, Jonnakuty C, LaMonte BH, Holzbaur EL, Tokito M, Mann E, Floeter MK, Bidus K, Drayna D, Oh SJ, Brown RH Jr, Ludlow CL, Fischbeck KH. Mutant dynactin in motor neuron disease. Nature Genetics 33(4):455–6, 2003.
- Drayna D, Coon H, Kim U-K, Elsner T, Cromer K, Otterud B, Baird L, Peiffer A, Leppert M. Genetic analysis of a complex trait in the Utah Genetic Reference Project: a major locus for PT taste ability on chromosome 7q and a secondary locus on chromosome 16p. Human Genetics 112:567–572, 2003.
- Kim UK, Jorgenson E, Coon H, Leppert M, Risch N, Drayna D. Positional cloning of the human quantitative trait locus underlying taste sensitivity to phenylthiocarbamide. Science 299(5610):1221–1225, 2003.
- Shugart YY, Mundorff J, Kilshaw J, Doheny K, Doan B, Wanyee J, Green E, Drayna D. Results of a genome-wide linkage scan for stuttering. American Journal of Medical Genetics DOI:10.1002/ajmg.a.20347, 2003.
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