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Genetic and phenotypic variation among Galaxias maculatus populations reflects contrasting landscape effects between northern and southern Patagonia


Carrea, C and Cussac, VE and Ruzzante, DE, Genetic and phenotypic variation among Galaxias maculatus populations reflects contrasting landscape effects between northern and southern Patagonia, Freshwater Biology, 58, (1) pp. 36-49. ISSN 0046-5070 (2013) [Refereed Article]

Copyright Statement

Copyright 2012 Blackwell Publishing Ltd

DOI: doi:10.1111/fwb.12036


1. Understanding the influence of landscape characteristics on genetic and phenotypic intraspecific variability can yield insights into how evolutionary processes work as well as provide essential information for the conservation of biodiversity.

2. Our aim was to compare the genetic structure and phenotypic variation among Galaxias maculatus populations inhabiting two Atlantic Ocean river basins in Patagonia in relation to historical and contemporary landscape characteristics associated with latitude.

3. Population genetic analysis (based on eight microsatellite loci, 505 individuals) indicates that genetic structure is more pronounced in the Rio Negro basin (RN) at 3941 degrees S (10 localities) than in the southernmost Santa Cruz River basin (SCR) at 4950 degrees S (seven localities). Spatial autocorrelation analysis showed different effects of geographic distance in shaping population differentiation patterns in the two basins.

4. While in northern Patagonia, fragmented populations could have survived the severity of Quaternary climate cycles, at higher latitudes G. maculatus populations were probably extirpated by extensive ice sheets. Extant populations in the upper reaches of the southernmost basin probably originated from refugia close to the Atlantic Ocean.

5. Based on otolith microchemistry, we have documented facultative diadromy for the first time for the species in the SCR basin, while no evidence of migration to the sea was found in individuals from the RN basin. Vertebral number increased with latitude, and within the SCR basin, the higher counts are possibly associated with a migratory life style.

Item Details

Item Type:Refereed Article
Keywords:facultative diadromy, Galaxias maculatus, genetic structure, intraspecific variation, microsatellite markers, vertebral count
Research Division:Biological Sciences
Research Group:Genetics
Research Field:Genetics not elsewhere classified
Objective Division:Environmental Management
Objective Group:Fresh, ground and surface water systems and management
Objective Field:Fresh, ground and surface water biodiversity
UTAS Author:Carrea, C (Dr Cecilia Carrea)
ID Code:120010
Year Published:2013
Web of Science® Times Cited:19
Deposited By:Biological Sciences
Deposited On:2017-08-08
Last Modified:2017-10-18

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