Quantitative Genetics of the Aging of Reproductive Traits in the Houbara Bustard

PLoS One. 2015 Jul 28;10(7):e0133140. doi: 10.1371/journal.pone.0133140. eCollection 2015.

Abstract

Do all traits within an organism age for the same reason? Evolutionary theories of aging share a common assumption: the strength of natural selection declines with age. A corollary is that additive genetic variance should increase with age. However, not all senescent traits display such increases suggesting that other mechanisms may be at play. Using longitudinal data collected from more than 5400 houbara bustards (Chlamydotis undulata) with an exhaustive recorded pedigree, we investigated the genetics of aging in one female reproductive trait (egg production) and three male reproductive traits (courtship display rate, ejaculate size and sperm viability), that display senescence at the phenotypic level. Animal models revealed an increase in additive genetic variance with age for courtship display rate and egg production but an unexpected absence of increased additive genetic variance for ejaculate size and no additive genetic variance for sperm viability. Our results suggest that the mechanisms behind the senescence of some traits are linked with a change in genetic expression, whereas for some other traits, aging may result from the constraints associated with physiological wear and tear on the organism throughout the life of the individual.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / genetics*
  • Animals
  • Birds / physiology*
  • Clutch Size
  • Courtship
  • Endangered Species
  • Female
  • Genetic Variation
  • Longitudinal Studies
  • Male
  • Models, Genetic
  • Morocco
  • Reproduction / genetics*
  • Semen / physiology
  • Sexual Behavior, Animal
  • Spermatozoa / physiology

Grants and funding

Stéphane Chantepie's work is funded by a Phd grant from the Centre National de la Recherche Scientifique (National Center for Scientific Research). SC, CT, AC and AR were funded by the French ANR (grant ANR-12-ADAP-0006). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Reneco Wildlife Preservation provided support in the form of a salary for author YH and data collection used in the manuscript but did not have any additional role in the analysis, decision to publish, or preparation of the manuscript. The specific role of this author is articulated in the ‘author contributions’ section.