Special to LiveScience
often conjures visions of mutant offspring,
but scientists now find it can have its
upside in the wild.
in the wild often avoid close kin as mates,
causes harmful genes that might otherwise
recede into the background to manifest
in progeny more often. While animal breeders
often practice inbreeding to cultivate
desirable traits, they must then cull
recent theoretical predictions suggest
that, at times, the benefits of inbreeding
might outweigh the costs. Now evolutionary
biologist Timo Thünken at the University
of Bonn in Germany and his colleagues
has discovered real-life evidence in support
of these predictions.
scientists investigated the African cichlid
Pelvicachromis taeniatus [image],
a small monogamous fish that lives in
the rivers and creeks of Cameroon and
Nigeria. Males occupy caves,
while females compete with each other
initially wanted to investigate whether
P. taeniatus avoid kin as mating partners,
because it has been shown in other species
that inbred offspring have disadvantages-for
example, increased mortality," Thünken
we conducted a female choice experiment,"
he recalled. This involved aquariums with
breeding caves for males and hiding places
for rejected females.
our expectations, females did not avoid
brothers, but even preferred them,"
Thünken told LiveScience. This proved
true in 17 of 23 experiments.
parents in the species care for their
young to protect them against predators,
the researchers noted. This requires high
levels of cooperation.
kinship generally favors cooperation,
Thünken and his colleagues theorized
related parents did a better job of cooperating
than non-kin. Their observations supported
their ideas, finding that inbreeding pairs
spent significantly more time accompanying
their free-swimming young. They also discovered
males of inbreeding pairs spent significantly
more time guarding breeding caves and
were half as likely to attack their mates.
researchers curiously found that inbreeding
did not appear to lead to higher rates
of harmful gene
expression. However, Thünken and
his colleagues noted inbreeding might
affect traits they have not yet studied,
such as the fertility
scientists plan to look next at the level
of inbreeding in natural populations of
the fish, the fitness consequences of
inbreeding and the mechanisms of kin
recognition in the species.
and his colleagues reported their findings
in the February 6 issue of the journal