Biology Reference
In-Depth Information
the forest and feeding on wild animals (
Brown et al. 2011
). Populations of this
mosquito, especially those that have invaded areas outside Africa, have devel-
oped the ability to breed in human habitats and feed on humans.
Brown et al.
(2011)
hypothesized that all “domesticated” populations are genetically related
and represent a single domestication event. The alternative hypothesis was
that association with humans developed multiple times independently within
Ae. aegypti
populations.
Brown et al. (2011)
sampled 24 populations by using
12 polymorphic microsatellite loci and found two distinct genetic clusters, one
of which included all populations outside of Africa that were “domesticated,”
and the other that included both domestic and wild populations in Africa. The
authors concluded that domestication occurred in Africa independently from
domestication elsewhere. The estimates of genetic diversity supported the
hypothesis that
Ae. aegypti
originated in Africa.
13.7.6.3 Bumblebees from Greenhouses Invade Wild Conspecific Populations
Bumblebees (
Bombus
species) are used to pollinate greenhouse crops, especially
tomatoes and peppers, because they are efficient and easy to handle. The col-
onies are mass reared and sold by commercial companies and are transported
around the world. Concerns have been raised about the effects of such large-
scale releases on endemic populations of the same species. Other concerns
include fears that the commercial bees may displace native species, or that they
may spread diseases into wild populations. The effect of releasing bumblebees
into greenhouses in a geographic area where conspecific endemic bees are pres-
ent was analyzed by comparing microsatellite DNA from greenhouse and wild
bumblebee populations (
Bombus terrestris
) in Poland (
Kraus et al. 2010
). The
results indicated that there is “strong genetic introgression from the sampled
greenhouse populations into the adjacent populations.” However, wild popula-
tions more distant from the greenhouses had less genetic admixture than those
populations close to the greenhouses. The impact of such introgression on the
endemic bees is unknown.
13.7.6.4 The Tobacco Aphid in the New World
The tobacco aphid,
Myzus persicae nicotianae
, is an invasive pest in Chile
(
Zepeda-Paulo et al. 2010
). Seven microsatellite loci were sampled from
American and European countries to identify the potential source population(s).
The data suggest that the tobacco aphid came from Europe and/or Asia to North
America and then to South America. The authors present evidence that there
were multiple introductions into North America and that a strong bottleneck
occurred when the aphids were introduced into South America.
