Background: Although genetic variations are heritable, some quantitative traits like longevity
may have non-genomic influence on heritability. Laboratory-selected inbred strains of extended
longevity phenotype of Drosophila offer an opportunity to study the inheritance of longevity.
Objective: The aim of the study was to examine the heritability of longevity in an extended longevity
phenotype of Drosophila melanogaster using reciprocal cross effects in F1 and F2 generations.
Methods: Lifespan variations of virgin and mated flies in parent, F1 and F2 generations were investigated
using reciprocal crosses between normal and long lifespan lines of inbred population of D.
melanogaster. Heterosis, narrow-sense heritability, recombination loss, maternal effect and overdominance
with respect to survivorship in virgin and mated flies were analyzed.
Results: Virgin flies lived longer than mated flies. There was no significant effect of mid-parent
heterosis, recombination loss and overdominance on variations in longevity, whereas, significant
maternal effect and narrow-sense heritability were observed in mated and virgin flies, respectively.
Conclusion: Absence of heterosis in our study population of Drosophila phenotypes could be due
to the lack of genetic heterogeneity. The heritability of the longevity trait in an inbred extended
longevity phenotype depends on the variations in genetic and environmental factors.