Candidate bird species for use in aging research.

Birds live about 3 times as long as an average mammal of similar size. They exhibit this remarkable resistance to the degenerative processes of aging despite traits such as elevated body temperature, a rapid metabolic rate, and high blood glucose that might lead one to expect them to be especially short-lived. Although birds appear to age slowly, the patterns of age-related deterioration and development of disease parallel in many ways those of mammals such as humans. Therefore, birds may reveal novel mechanisms of resistance to senescence. A previous impediment to the use of birds in modern biomedical research was the inability to perform targeted genetic manipulations, which has revolutionized the use of other model species. But with the publication of the whole genome sequence of two bird species and the development of gene knockdown technology and tissue-specific transgenesis, this impediment seems to be disappearing. At least five bird species deserve special attention for development as models of successful aging. Three of these species--budgerigars, canaries, and zebra finches--are common cage birds and are already used extensively in the study of vocal learning and sustained neurogenesis in adulthood. In addition, two wild species--the European starling and the house sparrow--may also make excellent models for aging research.