2. Behavioral Biology TALKS - Deutsche Zoologische Gesellschaft

of the art in this field in relation to an ecologically compelling group of marine
mammals, the Pinnipedia (seals and sea lions). In particular I will draw upon novel
insights from an exceptionally detailed long-term study of a breeding colony of
Antarctic fur seals (Arctocephalus gazella) at South Georgia in the Southern Atlantic.
Chair: Alexander Kupfer
�57 Adina Renz M 627 / 14:00
The mosaic evolution of the Dlx4 gene in the sauropsid lineage: Phylogenetic and
expression analysis
Authors: Adina J. Renz 1 , Axel Meyer 1 , Shigehiro Kuraku 2
Affiliations: 1 LS Zoology & Evolutionary Biology, University of Konstanz; 2 Genome
Resource and Analysis Unit, Center for Developmental Biology (CDB), Kobe,
Japan
Most derived vertebrates appear to possess six paralogs of the homeobox-containing
distal-less (dll) gene, the Dlx genes. Commonly, these transcription factors are found
as three convergently transcribed pairs in the genomes of most model
vertebrates. Previous studies have reported conserved non-coding elements
inside these clusters, suggesting their contribution to the maintenance of
syntenic relationships. However, the intactness of the Dlx3-Dlx4 cluster has not been
shown continuously in the genomes of all vertebrates. Generally, this cluster is
known to be more derived functionally and phylogenetically. Inside the Dlx3-Dlx4
cluster, Dlx4 shows a higher rate of evolutionary change than Dlx3. One previous
study reported that the chicken Dlx4 gene is a pseudogene, lacking a start codon,
and so far, no intact cluster structure could be demonstrated for chicken. In this
study we report the occurrence of Dlx4 orthologs, proven by maximum-likelihood
phylogenetic analyses, and the existence of the intact Dlx3-Dlx4 cluster,
employing already published sequence data of sauropsid species. Additional
sequencing was performed for Dlx4 in Anolis carolinensis, the turtle species
Pelodiscus sinensis and Emydura subglobosa, as well as the gecko Paroedura picta.
We also investigated the expression patterns of Dlx4 during chick development,
and we compared this Dlx4 expression to previously described expression data of
Dlx3 and Dlx5. The in situ hybridization analysis of chick embryos at stage 23 show an
expression of Dlx4 in the branchial arches 1 and 2, whereas an expression in the nasal
pits and the apical ectodermal ridge was not detected in comparison to Dlx3 and
Dlx5.
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