title: Deceleration of age-specific mortality rates in chromosomal homozygotes and heterozygotes of Drosophila melanogaster.
abstract: Age-specific mortality trajectories were estimated in mixed-sex cohorts of D. melanogaster. We studied 22,000 flies that were either second-chromosome homozygotes or heterozygotes with a randomized genetic background. Broad-sense heritabilities for longevity were estimated to be 6% for males and 9% for females. Heterozygotes lived longer than homozygotes on average, but there were exceptions to the usual heterotic pattern; in several crosses parental homozygotes had average life spans as long as that of their F1 heterozygotes. Estimated age-specific mortality rates were found to decelerate at advanced ages in both homozygotes and heterozygotes. The mortality models that best fit the data are the logistic model and the two-stage Gompertz model, both of which produce mortality trajectories that level off at advanced ages. Old-age mortality deceleration is not peculiar to inbred Drosophila.
authors.affiliation: Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul 55108, USA.
authors.forename: H H
authors.initials: HH
authors.lastname: Fukui
authors.forename: L
authors.initials: L
authors.lastname: Ackert
authors.forename: J W
authors.initials: JW
authors.lastname: Curtsinger
mesh_terms: D000818:Animals; D004331:Drosophila melanogaster / Q000235:genetics / Q000502:physiology*; D005260:Female; D006579:Heterozygote; D006720:Homozygote; D016015:Logistic Models; D008136:Longevity; D008297:Male; D009026:Mortality