2. Behavioral Biology TALKS - Deutsche Zoologische Gesellschaft

����217 Hans Recknagel
Linkage mapping of two ecologically and morphologically divergent Midas cichlids
(Amphilophus spp.)
Authors: Hans Recknagel 1 , Kathryn R. Elmer 1 , Axel Meyer 1
Affiliation: 1 University of Konstanz
Cichlid fishes are an excellent model system for studying speciation and adaptive
radiations due to their tremendous species richness and phenotypic variability.
Research, so far, has mostly focused on African rift lake cichlids, but the Neotropical
Midas cichlid species flock (Amphilophus spp.) also offers a tractable model system
with a variety of rather distinct phenotypes. Here we apply double-digest restrictionsite
associated DNA sequencing (ddRADSeq) in order to obtain a high-density linkage
map of an interspecific cross between the benthic A. astorquii and the limnetic A.
zaliosus, both endemic to Lake Apoyo, Nicaragua. 343 F2-hybrids were genotyped for
a total of 755 RAD markers. 25 linkage groups span over a distance of 1427 cM with
an average marker spacing distance of 1.95 cM, almost matching the total number of
chromosomes (n=24). Regions of segregation distortion were identified in five linkage
groups. The genetic map will facilitate the detection of eco-morphologically relevant
adaptive traits in Midas cichlids. We performed comparative genomic analyses in
teleosts and found highly conserved synteny between African cichlids and
Neotropical cichlids, and less conserved synteny between cichlids and other teleosts.
These results suggest that the cichlid’s phenotypic variability does not correlate with
a high degree of chromosomal rearrangements, neither do Midas cichlids exhibit a
higher mutation rate compared to other teleosts. Our linkage mapping analysis
shows that ddRADSeq is an appropriate method to develop hundreds of markers and
to construct high-density linkage maps even in genetically very young populations.
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