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Variation and Adaptation in the Guppy, Poecilia reticulata

 
Project Leader:
Christine Dreyer
Department:
Molecular Biology - Weigel
Secretary: 
Hülya Wicher
Phone:
+49 7071 601-1411
Fax:
+49 7071 601-1412
Staff:
Alphabetical List

Introduction

We study guppies as a vertebrate model for natural variation and adaptation to different river habitats in the wild, for sex-linked inheritance of male ornaments and evolution of sex chromosomes. Recently we published a dense, genetic map of all 23 linkage groups of the guppy and used this map to identify genetic loci important for male ornaments, body size and shape by QTL mapping. The polymorphic nuclear SNP markers that we developed for genetic mapping we also used for population genetics in a wide array of wild guppies from Trinidad and Venezuela. This revealed regions of the genome under selection that we study by second generation sequencing of genomic BACs. Currently, we are developing more markers linked to expressed genes as well as anonymous markers, by Illumina sequencing the transcriptome and restriction enzyme site-linked sequence tags (RAD markers). These novel tools will greatly enhance resolution of the genetic map and allow us to study genes under selection in different river habitats. A focus of our research is the characterization of the differentiated sex determining region of the Y chromosome that also harbors male advantageous ornamental genes coupled to the SDL. As a cytogenetic tool we established guppy cell cultures of male genotype to be used for chromosome FISH and chromosome dissection. In addition, we study candidate genes for specification, migration and differentiation of pigment cells in male guppies as well as the development of their patterns. In collaboration with Felix Breden, we have investigated opsin photopigments and found polymorphisms in long wavelength opsins between different individuals and populations, indicative of positive selection on red and orange color perception.

Publications