The demography of slow aging in male and female Drosophila mutant for the insulin-receptor substrate homologue chico.
Hypomorphic mutants affecting the Drosophila insulin/IGF signal pathway are reported to increase longevity in females but not in males. To understand this sex-difference, we conducted a large-scale demographic study with three new isogenic strains of alleles at chico, the insulin-receptor substrate homologue. We verify that female dwarf homozygotes (ch1/ch1) and normal-sized heterozygotes (ch1/+) are long-lived, as originally reported. We find for the first time that male heterozygotes are long-lived relative to wildtype, by about 50%. The life span of male ch1/ch1 is similar to that of wildtype but these dwarf males age at a slow demographic rate. The levels of demographic frailty and of age-independent mortality are elevated in ch1/ch1 males, counteracting the effect of slow aging upon life expectancy. Mortality deceleration occurs amongst the oldest-old wildtype adults, as seen in many organisms. Remarkably, in similarly sized cohorts of male and female ch1/ch1 and of male ch1/+ mortality deceleration is absent. Mortality deceleration is a phenotype of chico.
Tu
Meng-Ping
MP
Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, USA.
Epstein
Diane
D
Tatar
Marc
M
D000375:Aging / Q000235:genetics*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D029721:Drosophila Proteins / Q000172:deficiency / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D004392:Dwarfism / Q000235:genetics / Q000378:metabolism; D005260:Female; D006579:Heterozygote; D006720:Homozygote; D007328:Insulin / Q000378:metabolism; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008017:Life Expectancy; D008136:Longevity / Q000235:genetics*; D008297:Male; D009026:Mortality; D009154:Mutation / Q000235:genetics*; D011972:Receptor, Insulin / Q000235:genetics* / Q000378:metabolism; D012727:Sex Characteristics
D002352:Carrier Proteins; D029721:Drosophila Proteins; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; C120233:chico protein, Drosophila; D011972:Receptor, Insulin