Quantitative trait loci mapping in cichlid fishes: Aulonocara koningsi x Metriaclima mbenjii and Labidochromis caeruleus x Labeotropheus trewavasae

Since the time of Darwin, biologists have sought to understand the
evolution and origins of phenotypic variation. To understand the genetic
and molecular sources of morphological differences, we capitalize on the
cichlid fish system. Cichlids of the East African Rift Lakes have
undergone an extensive adaptive radiation, including variation in body
shape, head shape, and pigmentation. These morphological differences are
often intimately linked to the ecology and behavior of these animals.
Here, we investigate the genetic basis of these phenotypes using
quantitative trait loci (QTL) mapping using four genera of Lake Malawi
cichlids and two F2 hybrid populations. The first hybrid cross is between
Aulonocara koningsi, which lives in the open sandy region and feeds
insects from the open sand, and Metriaclima mbenjii, an omnivore
rock-dwelling fish. The second cross is between Labidochromis caeruleus, a
suction-feeding insectivore that swims continuously searching for prey,
and Labeotropheus trewavasae, which feeds by biting or scraping attached
algae from the rocks in its benthic habitat. Such work can provide
insights into the molecular basis of phenotypic adaptation, the genetic
architecture of morphology, and the evolution of cichlid fishes.