Genetic similarity between parents predicts hatching failure: non-incestuous
inbreeding in the great reed warbler
Bensch, S., Hasselquist, D. & von Schantz, T.
Evolution 48:317-326. 1994.
Abstract
The DNA fingerprinting technique was used to find the true pedigrees
and to detect the overall genetic similarity between mates of great reed
warblers (Acrocephalus arundinaceus) at an isolated breeding site in Sweden.
The study covered four years preceded by three years when almost all adults
and nestlings in the study area had been ringed. DNA fingerprinting revealed
that the putative father had sired the overwhelming majority of the young.
The mate's genetic similarity, revealed as the proportion of bands shared
in RFLP patterns, was high compared to other species of wild birds. Also,
band sharing was higher between mates native to the area than between pairs
where the female was experimentally introduced from a distant breeding
site. Hatching success of eggs was negatively correlated with the degree
of genetic similarity between the mates despite the fact that pedigree
data suggest outbreeding. These are the first data showing that there is
a significant fitness cost associated with the choice of a mate which has
high genetic similarity, even if it is not a close kin. This cost might
be due to generalized deleterious consequences of genome-wide inbreeding,
in the present study possibly accentuated by recent population bottlenecks.