Pleiotropy and eye degeneration in cavefish

Jeffery, William R.

doi:10.1038/hdy.2010.7

Cited by 35 publications

(29 citation statements)

References 8 publications

(17 reference statements)

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“…Which genes correspond to the 12 QTLs associated with “eye size” in Astyanax cavefish [104]? Are some of them really pleiotropic developmental genes [83,105]? Are genetic linkage and QTL clusters controlling the concerted evolution of multiple traits in cave animals [69,104]?…”

Section: Resultsmentioning

confidence: 99%

Evolution of eye development in the darkness of caves: adaptation, drift, or both?

Rétaux

Casañe

2013

EvoDevo

116

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Animals inhabiting the darkness of caves are generally blind and de-pigmented, regardless of the phylum they belong to. Survival in this environment is an enormous challenge, the most obvious being to find food and mates without the help of vision, and the loss of eyes in cave animals is often accompanied by an enhancement of other sensory apparatuses. Here we review the recent literature describing developmental biology and molecular evolution studies in order to discuss the evolutionary mechanisms underlying adaptation to life in the dark. We conclude that both genetic drift (neutral hypothesis) and direct and indirect selection (selective hypothesis) occurred together during the loss of eyes in cave animals. We also identify some future directions of research to better understand adaptation to total darkness, for which integrative analyses relying on evo-devo approaches associated with thorough ecological and population genomic studies should shed some light.

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Section: Resultsmentioning

confidence: 99%

Evolution of eye development in the darkness of caves: adaptation, drift, or both?

Rétaux

Casañe

2013

EvoDevo

116

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“…The forces driving the evolution of cave phenotypes are still debated, with strong advocacy for 1) neutral mutation and drift, 2) direct selection, and 3) indirect selection through pleiotropy (Protas et al 2007; Jeffery 2010; Wilkens 2010a, 2010b; Yoshizawa et al 2012). Although we believe that all three mechanisms are involved in cave evolution, the present results strongly support a pervasive role for selection, direct or indirect, in the process.…”

Section: Discussionmentioning

confidence: 99%

The Population Genomics of Repeated Evolution in the Blind Cavefish Astyanax mexicanus

Bradić

Teotónio

Borowsky

2013

Molecular Biology and Evolution

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Distinct populations of Astyanax mexicanus cavefish offer striking examples of repeatable convergence or parallelism in their independent evolutions from surface to cave phenotypes. However, the extent to which the repeatability of evolution occurred at the genetic level remains poorly understood. To address this, we first characterized the genetic diversity of 518 single-nucleotide polymorphisms (SNPs), obtained through RAD tag sequencing and distributed throughout the genome, in seven cave and three groups of surface populations. The cave populations represented two distinct lineages (old and new). Thirty-one SNPs were significantly differentiated between surface and old cave populations, two SNPs were differentiated between surface and new cave populations, and 44 SNPs were significantly differentiated in both old and new cave populations. In addition, we determined whether these SNPs map to the same locations of previously described quantitative trait loci (QTL) between surface and cave populations. A total of 25 differentiated SNPs co-map with several QTL, such as one containing a fibroblast growth factor gene (Fgf8) involved in eye development and lens size. Further, the identity of many SNPs that co-mapped with QTL was the same in independently derived cave populations. These conclusions were further confirmed by haplotype analyses of SNPs within QTL regions. Our findings indicate that the repeatability of evolution at the genetic level is substantial, suggesting that ancestral standing genetic variation significantly contributed to the population genetic variability used in adaptation to the cave environment.

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“…Therefore, the embryonic modifications in early Shh morphogen signaling seems to pleiotropically affect the developmental evolution of the cavefish brain (discussed in ref. 15). …”

Section: Gain Of Feeding Behaviormentioning

confidence: 99%

Feed or fight: A behavioral shift in blind cavefish

Rétaux

Elipot

2013

Communicative & Integrative Biology

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Within the species Astyanax mexicanus, there are several inter-fertile populations of river-dwelling sighted fish and cave-dwelling blind fish which have evolved morphological and behavioral adaptations. We have recently reported a developmental and neurophysiological basis for the loss of aggressive behavior in the blind cavefish morph of Astyanax. Using an appropriate behavioral assay, we have shown that surface Astyanax show intense dominance-related aggressiveness. The expression of this behavior is inversely correlated with the serotonin (5HT) levels in their hindbrain raphe nucleus. Moreover this behavior is not solely visually-evoked and has a genetic component. Conversely in cavefish, there is no raphe-driven dominance aggressiveness. Instead, the embryonic Sonic Hedgehog–dependent modification of the size of a serotonergic neuronal group localized in their hypothalamus causes a shift in their behavioral pattern: instead of fighting, they search for food. Here we further discuss the origin and nature of this behavioral shift.

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Pleiotropy and eye degeneration in cavefish

Cited by 35 publications

References 8 publications

Evolution of eye development in the darkness of caves: adaptation, drift, or both?

Evolution of eye development in the darkness of caves: adaptation, drift, or both?

The Population Genomics of Repeated Evolution in the Blind Cavefish Astyanax mexicanus

Feed or fight: A behavioral shift in blind cavefish

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