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Darwin believed that sexual selection accounts for the evolution of exaggerated male ornaments, such as the sword-like caudal fin extensions of male fishes of the genus Xiphophorus, that appear detrimental to survival. Swordtails continue to feature prominently in empirical work and theories of sexual selection; the pre-existing bias hypothesis has been(More)
BACKGROUND The annual fish Nothobranchius furzeri is the vertebrate with the shortest known life span in captivity. Fish of the GRZ strain live only three to four months under optimal laboratory conditions, show explosive growth, early sexual maturation and age-dependent physiological and behavioral decline, and express aging related biomarkers. Treatment(More)
Several attributes intuitively considered to be typical mammalian features, such as complex behavior, live birth and malignant disease such as cancer, also appeared several times independently in lower vertebrates. The genetic mechanisms underlying the evolution of these elaborate traits are poorly understood. The platyfish, X. maculatus, offers a unique(More)
The ISH protocol was adapted from ref. 25 with the following modifications: embryos were fixed overnight in 4% paraformaldehyde in 0.1 M MOPS pH 7.5, 0.5 M NaCl at 4 8C, washed in 0.05 M Tris-HCl pH 8, treated for 1 min with 10 mg ml 21 proteinase K in 0.05 M Tris-HCl pH 8 at 37 8C, followed by incubation in 1 M MOPS, 0.5 M NaCl, 0.1% Triton X-100 at 20 8C(More)
In mammals, the increase in gene dosage, in the form of polyploidy or involving chromosomal fragments, has deleterious effects [1]. Regulation of appropriate gene product amounts has to be warranted by complex dosage-compensation mechanisms. Lower vertebrates, on the other hand, cope very well with ploidy increase [2-4], implying either effective(More)
Small aquarium fish, like the medaka and zebrafish, offer an excellent opportunity to combine embryological, genetic and molecular analyses of vertebrate development. Pluripotent embryonic stem (ES) cells have enormous potential to study the totipotency and differentiation of cells and provide s bridge linking in vitro manipulations of the genome. In this(More)
During vertebrate development, many neurons depend for survival and differentiation on their target cells. The best documented mediator of such a retrograde trophic action is the neurotrophin nerve growth factor (NGF). NGF and the other known members of the neurotrophin family, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and(More)
The fish non–long-terminal-repeat (non-LTR) retro-transposon Rex3 has recently been isolated from the platyfish Xiphophorus maculatus (Volff et al. 1999). Complete versions of Rex3 encode a reverse transcrip-tase (RT) and an apurinic/apyrimidinic endonuclease (fig. 1). Rex3 belongs to the RTE family of non-LTR retrotransposons (Malik and Eickbush 1998;(More)
The discovery of a living coelacanth specimen in 1938 was remarkable, as this lineage of lobe-finned fish was thought to have become extinct 70 million years ago. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land.(More)