Multi‐trait evolution in a cave fish, Astyanax mexicanus

  title={Multi‐trait evolution in a cave fish, Astyanax mexicanus},
  author={Meredith E. Protas and Inna Tabansky and Melissa D. Conrad and Joshua B. Gross and Oriol Vidal and Clifford J. Tabin and Richard Borowsky},
  journal={Evolution \& Development},
SUMMARY When surface species colonize caves, a characteristic suite of traits eventually evolves over time, regardless of species. The genetic basis of the inevitable appearance of these very similar phenotypes was investigated through quantitative trait loci (QTL) mapping of 12 traits that differ significantly between the recently evolved (<1 Myr). Mexican cave tetra and its surface conspecific. The traits were a representative set, including eye size, pigment cell numbers, chemical… 

A chromosome-level genome of Astyanax mexicanus surface fish for comparing population-specific genetic differences contributing to trait evolution

A high-resolution, chromosome-level surface fish genome is presented, enabling the first genome-wide comparison between surface fish and cavefish populations and confirming the essential role of a gene within an eye size QTL, rx3, in eye formation in A. mexicanus.

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

The 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.

Genome Editing Using TALENs in Blind Mexican Cavefish, Astyanax mexicanus

TALENs were designed to target two genes that contain coding changes in cavefish relative to surface fish and map to the same location as QTL for pigmentation, oculocutaneous albinism 2 (oca2) and melanocortin 1 receptor (mc1r), and it was found that surface fish genes can be mutated using this method.

Genetic mapping of metabolic traits in the blind Mexican cavefish reveals sex-dependent quantitative trait loci associated with cave adaptation

This study reveals previously unappreciated genomic regions associated with blood glucose regulation, body condition, gonad size, and internal organ morphology in cavefish and finds an interaction between sex and metabolism-related traits in A. mexicanus.

Characterizing the genetic basis of trait evolution in the Mexican cavefish

A pipeline to test individual fish for multiple traits provides a novel system to identify genes that underlie naturally occurring genetic variation in morphological and behavioral traits and reveals an association between body length and slower escape reflex in cavefish.

Genetics and hybridization in surface and cave Astyanax (Teleostei): a comparison of regressive and constructive traits

Neither crossing analysis nor QTL mapping revealed that eye reduction is pleiotropically antagonistically related to the increase of taste buds or lateral line sense, which suggests that Astyanax cave fish are subjected to mosaic evolution.

In-Frame Indel Mutations in the Genome of the Blind Mexican Cavefish, Astyanax mexicanus

A genome-wide screen for in-frame indels using alignments of RNA-sequencing reads to the draft cavefish genome reveals previously unappreciated traits evolving in this species under environmental pressures and provides insight to genetic changes underlying convergence of organisms evolving in complete darkness.

The cavefish genome reveals candidate genes for eye loss

The first de novo genome assembly for Astyanax mexicanus cavefish is presented, contrast repeat elements to other teleost genomes, identify candidate genes underlying quantitative trait loci (QTL), and assay these candidate genes for potential functional and expression differences.

Utilizing the blind cavefish Astyanax mexicanus to understand the genetic basis of behavioral evolution

  • J. Kowalko
  • Biology
    Journal of Experimental Biology
  • 2020
Astyanax mexicanus is an excellent model system for examining the genetic basis of complex traits and multiple avenues of new research that can be pursued using gene editing tools are identified, and how these will enhance the understanding of behavioral evolution is discussed.



Regressive Evolution in the Mexican Cave Tetra, Astyanax mexicanus

Mapping a cave fish genome: polygenic systems and regressive evolution.

RAPD fingerprinting is used to generate anonymous DNA markers in the fish Astyanax mexicanus, a species with both surface and cave populations and the results are the first direct demonstration that troglomorphic changes in this population are multifactorial.

Genetic analysis of cavefish reveals molecular convergence in the evolution of albinism

The generation of a genome-wide linkage map is described to allow quantitative trait analysis of evolutionarily derived morphologies in the Mexican cave tetra, a species that has, in a series of independent caves, repeatedly evolved specialized characteristics adapted to a unique and well-studied ecological environment.

Convergent evolution of the cavefish Astyanax (Characidae, Teleostei): genetic evidence from reduced eye‐size and pigmentation

This work has confirmed that in different cave populations of the cave-dwelling characid Astyanax, different mutations in the eye gene system have occurred, and that in cases where these non-functional rudimentary genes are recombined in hybrid specimens, gene expression may be restored.

Genetic divergence between cave and surface populations of Astyanax in Mexico (Characidae, Teleostei)

Both the microsatellite and mtDNA data suggest multiple origins of cave populations and the Chica and Sabinos/Tinaja/Pachon were founded after at least two independent invasions from surface populations.

Evidence for multiple genetic forms with similar eyeless phenotypes in the blind cavefish, Astyanax mexicanus.

An analysis of variation in the mitochondrial NADH dehydrogenase 2 (ND2) gene among different surface fish and cavefish populations identifies a minimum of two genetically distinctive cavefish lineages with similar eyeless phenotypes.

Domestication quantitative trait loci in Triticum dicoccoides, the progenitor of wheat

  • Junhua PengY. Ronin A. Korol
  • Biology, Medicine
    Proceedings of the National Academy of Sciences of the United States of America
  • 2003
The A genome of wheat may have played a more important role than the B genome during domestication evolution and the cryptic beneficial alleles at specific QTLs derived from T. dicoccoides may contribute to wheat and cereal improvement.

Pleiotropic Quantitative Trait Loci Contribute to Population Divergence in Traits Associated With Life-History Variation in Mimulus guttatus

Most detected QTL are pleiotropic, implying that the evolutionary shift between these annual and perennial populations is constrained, and there may be a shared genetic basis for floral divergence within and among species of Mimulus.

Widespread Parallel Evolution in Sticklebacks by Repeated Fixation of Ectodysplasin Alleles

Major phenotypic changes evolve in parallel in nature by molecular mechanisms that are largely unknown. Here, we use positional cloning methods to identify the major chromosome locus controlling

Cavefish as a model system in evolutionary developmental biology.

Genetic analysis indicates that multiple genes regulate eye degeneration, and molecular studies suggest that Pax6 may be one of the genes controlling cavefish eye degenerations, and further studies of the Astyanax system will contribute to the understanding of the evolution of developmental mechanisms in vertebrates.