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The consequences on fitness of equating family contributions: inferences from a drosophila experiment

Abstract

Here we present results of a Drosophila long term experiment where we study the fitness consequences of equating the number of breeding offspring contributed per family (EC) compared to a random contribution (RC) protocol. The EC strategy slows inbreeding and drift. However, it also prevents natural selection on fecundity and limits selection on viability to that occurring within families, and this includes purge against unconditionally deleterious alleles as well as adaptation to captive conditions. We used populations maintained with 5 or 25 single mated pairs, monitored inbreeding and selection intensity, and assayed competitive and non competitive fitness, as well as fecundity and viability components, in lines maintained with or without EC. In the small lines, EC showed modest advantage for viability during the whole experiment and for fitness up to generation 15 while, in the large lines, fitness increased steadily under both strategies, and EC led in the medium term to a slight fitness disadvantage. On the light of recent theory, these results can be explained as the joint consequence of new and standing deleterious mutations undergoing drift, inbreeding and selection and of adaptation to captive conditions.

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Acknowledgments

We are grateful to Carlos López-Fanjul for useful discussion and to Mauro Santos for providing the original Drosophila sample. This work was supported by grants CGL2008-02343/BOS from the Ministerio de Ciencia e Innovación and UCM-BSCH GR58/08-910433 from the Universidad Complutense.

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Correspondence to Aurora García-Dorado.

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Sánchez-Molano, E., García-Dorado, A. The consequences on fitness of equating family contributions: inferences from a drosophila experiment. Conserv Genet 12, 343–353 (2011). https://doi.org/10.1007/s10592-010-0143-3

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Keywords

  • Inbreeding depression
  • Purge
  • Conservation
  • Adaptation to captive conditions
  • Fitness components
  • Population number