title: Indy gene variation in natural populations confers fitness advantage and life span extension through transposon insertion.
abstract: Natural selection acts to maximize reproductive fitness. However, antagonism between life span and reproductive success frequently poses a dilemma pitting the cost of fecundity against longevity. Here, we show that natural populations of Drosophila melanogaster harbor a Hoppel transposon insertion variant in the longevity gene Indy (I'm not dead yet), which confers both increased reproduction and longevity through metabolic changes. Heterozygosity for this natural long-lived variant has been maintained in isolates despite long-term inbreeding under laboratory conditions and advantageously confers increased fecundity. DNA sequences of variant chromosome isolates show evidence of selective sweep acting on the advantageous allele, suggesting that natural selection acts to maintain this variant. The transposon insertion also regulates Indy expression level, which has experimentally been shown to affect life span and fecundity. Thus, in the wild, evolution reaffirms that the mechanism of heterozygote advantage has acted upon the Indy gene to assure increased reproductive fitness and, coincidentally, longer life span through regulatory transposon mutagenesis.
authors: Department of Molecular Biology, Cell Biology and Biochemistry, Division of Biology and Medicine, Brown University, Providence, RI 02912.
authors: Chen-Tseh
authors: CT
authors: Zhu
authors: Chengyi
authors: C
authors: Chang
authors: Robert A
authors: RA
authors: Reenan
authors: Stephen L
authors: SL
authors: Helfand
mesh_terms: D000818:Animals; D004251:DNA Transposable Elements; D029382:Dicarboxylic Acid Transporters / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D005298:Fertility / Q000235:genetics; D005786:Gene Expression Regulation; D056084:Genetic Fitness; D005838:Genotype; D006579:Heterozygote; D008136:Longevity / Q000235:genetics*; D010641:Phenotype; D011110:Polymorphism, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D012641:Selection, Genetic / Q000235:genetics*; D027981:Symporters / Q000235:genetics* / Q000378:metabolism
chemical_list: D004251:DNA Transposable Elements; D029382:Dicarboxylic Acid Transporters; D029721:Drosophila Proteins; C417606:Indy protein, Drosophila; D012333:RNA, Messenger; D027981:Symporters