Lawrence C Erway
PhD, California, Davis, to Present.
Our research is directed to identifying the genetic bases for hearing loss related to age and to noise exposure in mice. Some inbred strains of mice hear normally to advanced ages (2-3 years). Other strains of mice exhibit hearing loss at younger ages. Different F1 hybrid strains of mice variously exhibit normal hearing or loss of hearing, indicating the existence of three different recessive genes which contribute to hearing loss. Such genes segregate and assort among F2 and backcross progenies, and one gene maps to Chromosome 10. Selected inbred and hybrid strains of mice which do not exhibit age-related hearing loss are resistant to permanent, noise-induced hearing loss; other strains of mice are susceptible to permanent, noise-induced hearing loss before they exhibit any age-related hearing loss. Further studies are designed to identify and map genes for age-related hearing loss and to investigate the relationships between such genes and environmental factors, including noise exposure and ototoxic agents. (Mice are anesthetized and tested repeatedly for their hearing ability with a computerized system for evoking and averaging the brainstem response; this response occurs within six milliseconds after onset of the stimuli, namely clicks or pure-tones to 32 kHz.)