Isolation Driven Divergence in Osmoregulation in Galaxias maculatus (Jenyns, 1848) (Actinopterygii: Osmeriformes)
Author
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Ruiz Jarabo, Ignacio
Author
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González Wevar, Claudio
Author
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Oyarzún, Ricardo
Author
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Fuentes, Juan
Author
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Poulin, Elie
Author
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Beltrán, Carlos
Author
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Vargas Chacoff, Luis
Admission date
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2016-11-16T19:52:45Z
Available date
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2016-11-16T19:52:45Z
Publication date
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2016
Cita de ítem
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PLoS One 11(5): e0154766 May 2016
es_ES
Identifier
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10.1371/journal.pone.0154766
Identifier
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https://repositorio.uchile.cl/handle/2250/141230
Abstract
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Background
Marine species have colonized extreme environments during evolution such as freshwater habitats. The amphidromous teleost fish, Galaxias maculatus is found mainly migrating between estuaries and rivers, but some landlocked populations have been described in lakes formed during the last deglaciation process in the Andes. In the present study we use mtDNA sequences to reconstruct the historical scenario of colonization of such a lake and evaluated the osmoregulatory shift associated to changes in habitat and life cycle between amphidromous and landlocked populations.
Results
Standard diversity indices including the average number of nucleotide differences (Pi) and the haplotype diversity index (H) indicated that both populations were, as expected, genetically distinctive, being the landlocked population less diverse than the diadromous one. Similarly, pairwise G(ST) and N-ST comparison detected statistically significant differences between both populations, while genealogy of haplotypes evidenced a recent founder effect from the diadromous stock, followed by an expansion process in the lake. To test for physiological differences, individuals of both populations were challenged with a range of salinities from 0 to 30 ppt for 8 days following a period of progressive acclimation. The results showed that the landlocked population had a surprisingly wider tolerance to salinity, as landlocked fish survival was 100% from 0 to 20 ppt, whereas diadromous fish survival was 100% only from 10 to 15 ppt. The activity of ATPase enzymes, including Na+/K+-ATPase (NKA), and H+-ATPase (HA) was measured in gills and intestine. Activity differences were detected between the populations at the lowest salinities, including differences in ATPases other than NKA and HA. Population differences in mortality are not reflected in enzyme activity differences, suggesting divergence in other processes.
es_ES
Patrocinador
dc.description.sponsorship
University of Cadiz
UCA 2009-074-FPI
Instituto de Ecologia y Biodiversidad (IEB)
P05-002 ICM
PFB 023
Fondecyt (Chile)
1151375
1160877
Fondap-IDEAL (Chile)
15150003
Fondecyt
3120075
11140087