"Dépression de consanguinité associée à des maladies dans une population importante et ouverte de corneilles coopératives"

Proceedings of the Royal Society B - Biological Sciences
7 June 2009 vol. 276 no. 1664 2057-2064
doi: 10.1098/rspb.2008.1852

Disease-mediated inbreeding depression in a large, open population of cooperative crows

1. Andrea K. Townsend1,*,
2. Anne B. Clark2,
3. Kevin J. McGowan3,
4. Elizabeth L. Buckles4,
5. Andrew D. Miller5 and
6. Irby J. Lovette1

-Author Affiliations

1.
1Fuller Evolutionary Biology Program, Cornell University Laboratory of Ornithology
159 Sapsucker Woods Road, Ithaca, NY 14850, USA
2.
2Department of Biological Sciences, Binghamton University
Binghamton, NY 13902, USA
3.
3Cornell University Laboratory of Ornithology
159 Sapsucker Woods Road, Ithaca, NY 14850, USA
4.
4Section of Anatomic Pathology, Department of Biomedical Sciences, Cornell University
Ithaca, NY 14853, USA
5.
5Division of Comparative Pathology, Harvard Medical School, New England Primate Research Center
One Pine Hill Drive, Southborough, MA 01772, USA

1. Author for correspondence (at256@cornell.edu)

Abstract

Disease-mediated inbreeding depression is a potential cost of living in groups with kin, but its general magnitude in wild populations is unclear. We examined the relationships between inbreeding, survival and disease for 312 offspring, produced by 35 parental pairs, in a large, open population of cooperatively breeding American crows (Corvus brachyrhynchos). Genetic analyses of parentage, parental relatedness coefficients and pedigree information suggested that 23 per cent of parental dyads were first- or second-order kin. Heterozygosity–heterozygosity correlations suggested that a microsatellite-based index of individual heterozygosity predicted individual genome-wide heterozygosity in this population. After excluding birds that died traumatically, survival probability was lower for relatively inbred birds during the 2–50 months after banding: the hazard rate for the most inbred birds was 170 per cent higher than that for the least inbred birds across the range of inbreeding index values. Birds that died with disease symptoms had higher inbreeding indices than birds with other fates. Our results suggest that avoidance of close inbreeding and the absence of inbreeding depression in large, open populations should not be assumed in taxa with kin-based social systems, and that microsatellite-based indices of individual heterozygosity can be an appropriate tool for examining the inbreeding depression in populations where incest and close inbreeding occur.

Généralités et Environnement

consanguinité et sensibilité aux maladies