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Título del libro: Biology And Evolution Of The Mexican Cavefish
Título del capítulo: Phylogeny and Evolutionary History of Astyanax mexicanus

Autores UNAM:
CARLOS SALVADOR PEDRAZA LARA;
Autores externos:

Idioma:
Inglés
Año de publicación:
2015
Palabras clave:

Convergence; Evolutionary history; Invasions; Lineage; Taxonomy


Resumen:

The troglobite populations (i.e., featuring cave-adapted traits) of the genus Astyanax inhabiting the Huasteca region, located in the Sierra Madre Oriental, in northeastern Mexico, corresponds to one of the most studied fish groups, among other reasons because it represents an outstanding opportunity to study local adaptation and trait evolution. Understanding evolutionary history of these populations is fundamental for studies involving trait evolution, as it provides accurate spatial and temporal frameworks. The latter notion, however, is still a matter of debate, as different studies have shown contrasting results about the number of colonizations and genetic structuring among caves. In concordance with its complex evolutionary history of genus Astyanax, its taxonomic arrangement is under intense modification. In addition, a complete phylogeny for species of the genus Astyanax is still missing. During the last two decades, several studies have tried to recover partial phylogenetic hypotheses for the genus, in particular in its northern distribution. At least 18 different lineages in Astyanax populations have been found derived from sequencing of mitochondrial and nuclear markers from Mesoamerica, and such diversity is not concordant with a single species designation. Population genetics studies have found a minimum of three, but up to five, independent origins of cave populations. To understand fully the historical dynamics of the cave invasions requires an outstanding effort to integrate information from geology, paleohydrology, demography, extensive geographic sampling, and long-term ancestry of the populations. © 2016 Elsevier Inc. All rights reserved.


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