X-Message-Number: 23918 Date: Sat, 17 Apr 2004 20:43:57 -0700 (PDT) From: Doug Skrecky <> Subject: an interesting model for vertebrate aging Proc R Soc Lond B Biol Sci. 2003 Nov 7;270 Suppl 2:S189-91. Extremely short lifespan in the annual fish Nothobranchius furzeri. Evolutionary theories of senescence postulate that lifespan is determined by the age-dependent decrease in the effects of natural selection. Factors that influence survival and reproduction at early life stages have a larger impact on fitness than factors that influence later life stages. According to these views, selection for rapid sexual maturation and a steep age-dependent decrease in fitness drive the evolution of short lifespans. Here, we report on the survival trajectory of Nothobranchius furzeri (Pisces: Ciprinodontidae): a member of a group of annual species found in temporary bodies of water whose life expectancy in the wild is limited to a few months. We find that maximum survival of N. furzeri in the laboratory is less than 12 weeks. The temporal trajectory of survival shows an age-dependent increase in the mortality rate that is typical of organisms with defined lifespans. The lifespan of N. furzeri is exceptionally short for a vertebrate: owing to its small size and the possibility of propagation in captivity, N. furzeri could be used as a convenient model for ageing research. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=23918