Evolution and Genetics of Epigean and Cave Astyanax fasciatus (Characidae, Pisces)

Wilkens, Horst

doi:10.1007/978-1-4613-1043-3_8

Cited by 305 publications

(403 citation statements)

References 75 publications

Supporting

Mentioning

382

Contrasting

Unclassified

Order By: Relevance

“…The neotropical characid fish Astyanax fasciatus (Cuvier 1819) (syn. A. mexicanus Filippi), which has developed a series of cave living populations within a restricted area in Northeastern Mexico, has become a model species in evolutionary research (Mitchell et al, 1977;Jeffery, 2001;Wilkens, 1988Wilkens, , 2004. The cave forms are characterised by the regressive evolution of all traits of which biological function is dependant on the presence of light; such as the eyes (Wilkens, 1988), the number of melanophores (Wilkens, 1988), the melanin pigmentation (Sadoǧ lu, 1955(Sadoǧ lu, , 1957Sadoǧ lu and McKee, 1969), the dorsal light reaction (Langecker, 1993) and the visually triggered aggressive behaviour (Hofmann and Hausberg, 1993).…”

Section: Introductionmentioning

confidence: 99%

“…A. mexicanus Filippi), which has developed a series of cave living populations within a restricted area in Northeastern Mexico, has become a model species in evolutionary research (Mitchell et al, 1977;Jeffery, 2001;Wilkens, 1988Wilkens, , 2004. The cave forms are characterised by the regressive evolution of all traits of which biological function is dependant on the presence of light; such as the eyes (Wilkens, 1988), the number of melanophores (Wilkens, 1988), the melanin pigmentation (Sadoǧ lu, 1955(Sadoǧ lu, , 1957Sadoǧ lu and McKee, 1969), the dorsal light reaction (Langecker, 1993) and the visually triggered aggressive behaviour (Hofmann and Hausberg, 1993). Traits that were constructively improved as adaptations to cave life include the number of taste buds (Schemmel, 1974), the angle of feeding on the ground (Schemmel, 1980), the ability of fat storage (Hueppop, 1989), the egg size (Hueppop and Wilkens, 1991), the number of free neuromasts of the lateral line sense (Wilkens unpublished), and aggressive behaviour as triggered by the lateral line sense (Hofmann and Hausberg, 1993).…”

Section: Introductionmentioning

confidence: 99%

“…It is possible to perform comparative studies of the specific evolving morphological, physiological and behavioural features in the closely related surface and cave forms and, of even greater importance, the interfertile surface and cave forms can still be hybridised. From their crosses, conclusions on the genetic basis and phenotypic manifestation of traits can be drawn (Wilkens, 1988). To date, the research of Astyanax cave fish has mainly focussed on two objectives: (1) To analyse the genetic basis of regressive evolution.…”

Section: Introductionmentioning

confidence: 99%

“…Although it is generally accepted that traits, which are important for living under the specific biotic cave conditions evolve constructively under the influence of selection, there has been much debate over whether regressive evolution is influenced by positive selection or through processes such as mutation/genetic drift, in which destructive mutations are not eliminated (Culver and Wilkens, 2000;Wilkens, 2004Wilkens, , 2007Jeffery, 2005). In the latter hypothesis, mutation pressure leads to an intermediate phase of variability, until functionless traits become rudimentary and finally completely disappear (Kosswig, 1940(Kosswig, , 1949(Kosswig, , 1959Wilkens, 1988). Several hypotheses have been suggested for the role of selection in eye regression.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Genes, modules and the evolution of cave fish

Wilkens

2010

Heredity

View full text Add to dashboard Cite

Cave fish provide a model system for exploring the genetic basis of regressive evolution. A proposal that regressive evolution (for example, eye loss) may result from pleiotropy, by selection on constructive traits (for example, improved taste) has received considerable recent interest as it contradicts the theory that regressive evolution results from neutral evolution. In this study, these theories are reviewed by placing the classical and molecular genetic studies of cave fish in a common framework. Sequence data and the wide range of intermediate sized eyes in hybrids between surface and cave fish suggest that currently there is no strong evidence supporting the notion that structural eye genes have been afflicted by destructive mutations. The hedgehog genes, which are suggested to reduce the primordial eye cup size in cavefish by expanded expression, are also not mutated. The as yet unidentified 'eye genes' revealed by crossing experiments seem primarily responsible for eye regression and determine eye development through hedgehog. Hybrids between different eye-reduced cave populations developing large 'back to surface eyes' support this. In such eyes, hh expression is restored by complementary restitution because of the recombination of 'eye genes', which were subjected to different destructive mutations in separately evolving cave fish populations. All regressive and constructive cave fish traits can be considered to result from genetic modules, each showing a comparable pattern of expression. The constructive and regressive modules are shown to inherit independently from each other, which does not support the view that eye regression is a spin off effect of the improvement of beneficial traits through pleiotropy.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Genes, modules and the evolution of cave fish

Wilkens

2010

Heredity

View full text Add to dashboard Cite

show abstract

“…However, except for a few well-studied cases, such as the loss of eyes and pigments in cavedwelling organisms, the evolutionary and genetic mechanisms underlying trait loss remain poorly understood (Fong et al 1995;Culver & Wilkens 2000). Trait reduction could occur through the fixation, via genetic drift, of selectively neutral mutations that cause degeneration of the nonfunctional trait (Haldane 1933;Muller 1949;Emerson 1961;Brace 1963;Wilkens 1988). Although this simple mechanism is generally supported by a wealth of evidence from the molecular evolution of pseudogenes and non-coding DNA (Wilkens 1988), the random fixation of degenerative mutations is liable to be a slow process and seems an unlikely explanation for cases where vestigialization has occurred repeatedly and rapidly (Porter & Crandall 2003).…”

Section: Introductionmentioning

confidence: 99%

Evolutionary vestigialization of sex in a clonal plant: selection versus neutral mutation in geographically peripheral populations

Dorken

Neville

Eckert

2004

Proc. R. Soc. Lond. B

View full text Add to dashboard Cite

The loss of traits that no longer contribute to fitness is widespread; however, the causative evolutionary mechanisms are poorly understood. Vestigialization could proceed through the fixation of selectively neutral degenerative mutations via genetic drift. Alternatively, selection may facilitate vestigialization if trait loss results in enhanced fitness. We tested these hypotheses using Decodon verticillatus, a clonal plant in which sexual sterility has arisen repeatedly in populations across the northern geographical range limit. We compared growth and survival of replicated genotypes from 7 sexually fertile and 18 sterile populations, over 3 years in a common environment. Survival of sterile genotypes was 53% greater than for fertile genotypes, but there was no difference in biomass accumulation. Almost all mortality, and hence increased performance of sterile genotypes, occurred during simulated overwinter dormancy. These observations suggest that selection has facilitated the vestigialization of sex, and thus do not support the neutral mutation hypothesis. The selective mechanism probably involves the relaxation of a genetic trade-off between sexual reproduction and survival: alleles that increase vegetative performance at the expense of sexual fertility are selected in geographically peripheral populations where sexual reproduction is suppressed by adverse environmental conditions.

show abstract

Cave Evolution

Gross

2012

Encyclopedia of Life Sciences

View full text Add to dashboard Cite

Cave‐dwelling animals are fascinating because of the phenotypic extremes they frequently exhibit, such as a reduced or complete loss of vision and pigmentation. Equally interesting is the fact that irrespective of taxonomic position, organisms colonising the subterranean environment converge on highly similar phenotypic deficits and improvements. Thus, a predictable suite of morphological, physiological and behavioural changes evolve in response to low nutrient conditions of the subterranean environment. Despite several decades of enquiry, the precise genetic and molecular underpinnings of cave‐associated changes are only beginning to be elucidated through the use of high‐resolution contemporary molecular and genetic techniques. Regressive phenotypic changes, those traits that are lost in derived lineages, are particularly interesting since they evolve in the absence of obvious selective value to the organism. Continuing research utilising an increasing number of emerging cave‐dwelling models offers the exciting prospect of clarifying longstanding problems in contemporary evolutionary biology. Key Concepts: Widespread convergence on cave‐associated (troglomorphic) characteristics is often attributed to the paucity of nutrition and overall stability of the cave environment. Cave‐adapted organisms are excellent models for the study of regressive phenotypic evolution, that is the loss of traits in derived organisms. The evolutionary mechanism(s) accounting for phenotypic loss in cave‐dwelling organisms (neutralism versus selection) remains unknown. Hybrid crosses between cave‐dwelling and intra‐specific ‘surface’ forms reveal numerous morphological changes associated with cave adaptation are recessive. Phenotypic analyses in subsequent generations reveal many cave‐associated characteristics arise through Mendelian (single locus) and complex (polygenic) patterns of inheritance. The cave environment likely represents an attractive habitat given that over 50 000 cave‐limited species are known worldwide, distributed across broad taxonomic groups. Contemporary cave research has advanced significantly over the last decade thanks to integrative analyses combining developmental, genetic, genomic, behavioural, physiological and population‐level approaches.

show abstract

Evolution and Genetics of Epigean and Cave Astyanax fasciatus (Characidae, Pisces)

Cited by 305 publications

References 75 publications

Genes, modules and the evolution of cave fish

Genes, modules and the evolution of cave fish

Evolutionary vestigialization of sex in a clonal plant: selection versus neutral mutation in geographically peripheral populations

Cave Evolution

Contact Info

Product

Resources

About