A proposito di Gambusie

Ancona, Umberto D'

doi:10.1080/11250003909436764

Cited by 6 publications

(1 citation statement)

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“…The taxonomy of mosquito fish has been revised repeatedly over time, beginning with Gambusia affinis (synonym Gambusia affinis affinis ) (Baird & Girard, ) and Gambusia holbrooki (Girard, 1859). In 1939, G. holbrooki and G. affinis were reclassified as a single species (D'Ancona, ). A few decades later, Rivas () suggested redesignating them subspecies, an historical classification also used by Rosen and Bailey () based upon several phenotypic traits, including fin ray counts.…”

Section: Introductionmentioning

confidence: 99%

A genetically distinct hybrid zone occurs for two globally invasive mosquito fish species with striking phenotypic resemblance

Wilk

Horth

2016

Ecology and Evolution

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Hybrid zones allow for the investigation of incipient speciation and related evolutionary processes of selection, gene flow, and migration. Interspecific dynamics, like competition, can impact the size, shape, and directional movement of species in hybrid zones. Hybrid zones contribute to a paradox for the biological species concept because interbreeding between species occurs while parental forms remain distinct. A long‐standing zone of intergradation or introgression exists for eastern and western mosquito fish (Gambusia holbrooki and G. affinis) around Mobile Bay, AL. The region has been studied episodically, over decades, making it perfect for addressing temporal dynamics and for providing a deeper understanding of the genetics of these periodically reclassified fishes (as species or subspecies). We used six microsatellite markers to assess the current population structure and gene flow patterns across 19 populations of mosquito fish and then compared our results with historical data. Genetic evidence demonstrates that the current hybrid zone is located in a similar geographic region as the historical one, even after three decades. Hybrid fish, however, demonstrate relatively low heterozygosity and are genetically distinct from western and eastern mosquito fish populations. Fin ray counts, sometimes used to distinguish the two species from one another, demonstrate more eastern (G. holbrooki) phenotype fish within the molecular genetic hybrid zone today. Mosquito fish are globally invasive, often found on the leading edge of flooded waters that they colonize, so the impact of hurricanes in the wake of climate change was also evaluated. An increase in the frequency and intensity of hurricanes in the hybrid region has occurred, and this point warrants further attention since hurricanes are known to move these aggressive, invasive species into novel territory. This work contributes to our classical understanding of hybrid zone temporal dynamics, refines our understanding of mosquito fish genetics in their native range, evaluates important genotype–phenotype relationships, and identifies a potential new impact of climate change.

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Section: Introductionmentioning

confidence: 99%