Zebrafish as a genetic model in biological and behavioral gerontology: where development meets aging in vertebrates--a mini-review.

Understanding the molecular mechanisms of aging in vertebrates is a major challenge of modern biology and biomedical science. This is due, in part, to the complexity of the aging process and its multifactorial nature, the paucity of animal models that lend themselves to unbiased high-throughput screening for aging phenotypes, and the difficulty of predicting such phenotypes at an early age. We suggest that the zebrafish genetic model offers a unique opportunity to fill in this gap and contributes to advances in biological and behavioral gerontology. Our recent studies demonstrated that this diurnal vertebrate with gradual senescence is an excellent model in which to study age-dependent changes in musculoskeletal and eye morphology, endocrine factors, gene expression, circadian clock, sleep and cognitive functions. Importantly, we have also found that the presence of a senescence-associated biomarker ('senescence-associated beta-galactosidase') can be documented during early zebrafish development and is predictive of premature aging phenotypes later in adult life. The availability of mutant 'genotypes' with identified aging 'phenotypes' in zebrafish, in combination with a wealth of information about zebrafish development and genetics, and the existence of multiple mutant and transgenic lines, should significantly facilitate the use of this outstanding vertebrate model in deciphering the mechanisms of aging, and in developing preventive and therapeutic strategies to prolong the productive life span ('health span') in humans.