Hybrid origin of a swordtail species (Teleostei: Xiphophorus clemenciae) driven by sexual selection

@article{Meyer2006HybridOO,
  title={Hybrid origin of a swordtail species (Teleostei: Xiphophorus clemenciae) driven by sexual selection},
  author={Axel Meyer and Walter Salzburger and Manfred Schartl},
  journal={Molecular Ecology},
  year={2006},
  volume={15}
}
The swordlike exaggerated caudal fin extensions of male swordtails are conspicuous traits that are selected for through female choice. Swords are one of only few examples where the hypothesis of a pre‐existing bias is believed to apply for the evolution of a male trait. Previous laboratory experiments demonstrated that females prefer males with longer swords and even females from some swordless species show an affiliation for males of sworded species. Earlier phylogenetic studies based on… 
Pre-existing biases for swords in mollies ( Poecilia )
TLDR
It seems as if pre-existing biases for sworded males are relatively basal to poeciliids and that existing phylogenetic relationships allow us to predict sensory biases.
Hybrid Speciation in a Marine Mammal: The Clymene Dolphin (Stenella clymene)
TLDR
Evidence for a marine mammal, Stenella clymene, arising through natural hybridization is presented and phylogenetic discordance between mitochondrial and nuclear markers is found, coupled with a pattern of transgressive segregation seen in the morphometric variation of some characters, support a case of hybrid speciation.
A phylogeographic investigation of the hybrid origin of a species of swordtail fish from Mexico
TLDR
The population structure within these species shows an isolation‐by‐distance (IBD) pattern and genetic differentiation between most populations is significant and high, and it is inferred that tectonic evolution in the Isthmus has greatly restricted gene flow between the southern and central IT populations of X. clemenciae and X. hellerii.
The Developmental and Genetic Architecture of the Sexually Selected Male Ornament of Swordtails
TLDR
The characterized sword transcriptional profile and genetic mapping approaches showed that the male ornament of swordtails develops from a sexually non-dimorphic prepattern of transcription factors in the caudal fin, indicating that during evolution ofswordtails a brain gene has been recruited for an additional function in establishing a male ornament.
Fgfr1 signalling in the development of a sexually selected trait in vertebrates, the sword of swordtail fish
TLDR
Results suggest that Fgf-signalling is involved upstream of msxC in the development of the sword and gonopodium in male swordtails, and point towards a disruption between the fgfr1/msxC network and its regulation by testosterone as a likely developmental cause for sword-loss in platyfish.
AN EVALUATION OF THE HYBRID SPECIATION HYPOTHESIS FOR XIPHOPHORUS CLEMENCIAE BASED ON WHOLE GENOME SEQUENCES
TLDR
The signature of hybridization in the genome of a putative hybrid species, Xiphophorus clemenciae, is investigated through whole genome sequencing of this species and its hypothesized progenitors, and it is found that X. cle menciae is unlikely to have been derived from admixture between its proposed parental species.
An organizer controls the development of the “sword,” a sexually selected trait in swordtail fish
TLDR
The findings suggest that the evolution of swords in swordtails required the acquisition of two developmental mechanisms: the establishment of signaling competence in prospective sword rays in the embryo or early larva, and its activation through androgen signaling in adult male fish.
Identification of novel genes involved in the development of the sword and gonopodium in swordtail fish
TLDR
It is shown that some of these genes follow distinct expression profiles in swords and gonopodia, suggesting differences in the genetic networks underlying the development of anal and caudal fin modifications.
PHYLOGENOMICS REVEALS EXTENSIVE RETICULATE EVOLUTION IN XIPHOPHORUS FISHES
TLDR
The results allow us to reexamine a long‐standing controversy about the evolution of the sexually selected sword in Xiphophorus, and demonstrate that hybridization has been strikingly widespread in the evolutionary history of this genus.
Transcriptomics of two evolutionary novelties: how to make a sperm-transfer organ out of an anal fin and a sexually selected “sword” out of a caudal fin
TLDR
Analysis of transcriptomic changes in response to testosterone treatment in the swordtail fish, Xiphophorus hellerii, aimed to better understand the architecture of the gene regulatory networks underpinning the development of these two evolutionary novelties.
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