Publications by authors named "Victor Cussac"

7 Publications

  • Page 1 of 1

Thermal effects in rainbow trout (Oncorhynchus mykiss) F1 embryos (farmed female × wild thermal-resistant male).

J Fish Biol 2021 Feb 24. Epub 2021 Feb 24.

Instituto Patagónico de Tecnologías Biológicas y Geoambientales, Universidad Nacional del Comahue - Consejo Nacional de Investigaciones Científicas y Técnicas, Bariloche, Argentina.

The aim of this work was to investigate the response of rainbow trout embryos (Oncorhynchus mykiss) (i.e., survival, size at hatching, time to hatching, malformations) to four incubation temperatures (5.8, 8.9, 14.0 and 16.8°C), taking into account the origin of the male parental genome and comparing pure farmed and F1 embryos (farmed female × wild thermal-resistant male). Several consequences of thermal stress were observed: lower accumulated thermal units (ATU) at hatching at high temperatures, and lower survival, shorter hatched free embryos and less-consumed yolk sac at extreme temperatures. The effect of the thermal-adapted male parental genome was shown only in the lower percentage of incompletely hatched free embryos in the F1 families. It appears that to obtain greater modification of thermal performance during early development, the adapted genome of the wild thermal-resistant population has to be included through maternal inheritance, thus producing a stabilized strain selected for domesticity, growth and thermal adaptation.
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http://dx.doi.org/10.1111/jfb.14711DOI Listing
February 2021

Biogeography, habitat transitions and hybridization in a radiation of South American silverside fishes revealed by mitochondrial and genomic RAD data.

Mol Ecol 2020 02 29;29(4):738-751. Epub 2020 Jan 29.

Department of Biological Sciences, George Washington University, Washington, DC, USA.

Rivers and lake systems in the southern cone of South America have been widely influenced by historical glaciations, carrying important implications for the evolution of aquatic organisms, including prompting transitions between marine and freshwater habitats and by triggering hybridization among incipient species via waterway connectivity and stream capture events. Silverside fishes (Odontesthes) in the region comprise a radiation of 19 marine and freshwater species that have been hypothesized on the basis of morphological or mitochondrial DNA data to have either transitioned repeatedly into continental waters from the sea or colonized marine habitats following freshwater diversification. New double digest restriction-site associated DNA data presented here provide a robust framework to investigate the biogeographical history of and habitat transitions in Odontesthes. We show that Odontesthes silversides originally diversified in the Pacific but independently colonized the Atlantic three times, producing three independent marine-to-freshwater transitions. Our results also indicate recent introgression of marine mitochondrial haplotypes into two freshwater clades, with more recurring instances of hybridization among Atlantic- versus Pacific-slope species. In Pacific freshwater drainages, hybridization with a marine species appears to be geographically isolated and may be related to glaciation events. Substantial structural differences of estuarine gradients between these two geographical areas may have influenced the frequency, intensity and evolutionary effects of hybridization events.
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http://dx.doi.org/10.1111/mec.15350DOI Listing
February 2020

Ten novel microsatellite loci characterized for a remarkably widespread fish: Galaxias maculatus (Galaxiidae).

Mol Ecol Resour 2009 Nov 22;9(6):1503-5. Epub 2009 Apr 22.

INIBIOMA (Universidad Nacional del Comahue-CONICET) Bariloche, 8400 Río Negro, Argentina Department of Biology, Dalhousie University, Halifax, NS, Canada B3H 4J1.

Ten polymorphic microsatellite markers (five tetra-, one compound tetra-, one octa- and three dinucleotides) were isolated and characterized for Galaxias maculatus, a fish species widely distributed in the Southern Hemisphere. Markers were tested in 89 individual samples from a single location and the number of alleles ranged between 2 and 28. Observed and expected heterozygosities ranged from 0.103 to 0.910 and 0.098 to 0.935 respectively. No evidence was detected for either linkage disequilibrium (P-values > 0.05 for each locus pair) or deviations from HWE (P-values > 0.05 for every loci).
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http://dx.doi.org/10.1111/j.1755-0998.2009.02702.xDOI Listing
November 2009

Isolation and characterization of 13 microsatellite loci for Percichthys trucha (Percichthyidae).

Mol Ecol Resour 2008 Jul;8(4):907-9

Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1, Universidad Nacional del Comahue-CONICET, Bariloche, 8400, Rio Negro, Argentina, Centro de Ciencias Ambientales, EULA, Universidad de Concepción and Centro de Investigaciones en Ecosistemas Patagónicos, Chile.

Thirteen polymorphic microsatellite loci are described for the South American freshwater fish Percichthys trucha. Number of alleles per locus ranged from two to 21 and observed heterozygosities ranged from 0.304 to 0.915 in a sample of 47 individuals from four different sampling locations.
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http://dx.doi.org/10.1111/j.1755-0998.2008.02112.xDOI Listing
July 2008

Contributions to the study of oviparity-viviparity transition: placentary structures of Liolaemus elongatus (Squamata: Liolaemidae).

J Morphol 2008 Jul;269(7):865-74

Universidad Nacional del Comahue, Quintral 1250, Bariloche, 8400 Río Negro, Argentina.

Liolaemus elongatus (Liolaemidae) is a viviparous, mainly lecithotrophic species with placental structures specialized for uptake of oxygen and inorganic nutrient transport. An allantoplacenta and an omphaloplacenta are present during early embryonic stages (25-28) and there is a moderate distension of the uterine wall and major glandular activity in the uterine mucosa and submucosa compared with nonpregnant females. The uterine epithelium increases in height, first as a growth in the height of some dispersed cells localized in all regions of the placenta, and later as groups of cells localized in the periembryonic and central-abembryonic regions. At embryonic stage 39, the allantoplacenta reaches its maximum extension around the yolk sac. Omphaloplacenta is restricted to the abembryonic zone, the yolk cleft limiting the newly formed isolated vitelline mass. At more advanced embryonic stages (39-42), the blood supply to the allantoplacenta's periembryonic zone increases, matching the profuse allantoic vascularization. At embryonic stage 42, a secondary cleft opens in the main vitelline mass, above the first yolk cleft, and allantoic blood vessels enter into this secondary cleft. This secondary cleft subdivides the vitelline mass into a large embryonic region connected to a much smaller abembryonic region. In L. elongatus most nutritional resources seem to be provided by the yolk that remains attached to the newborn for 2 or 3 days as an external supply. The embryo's wet weight doubles the weight of the decrease observed in vitelline mass. But the dry wet diminishes, evidencing the importance of the exchange of water and inorganic nutrients.
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http://dx.doi.org/10.1002/jmor.10632DOI Listing
July 2008

Climate control on ancestral population dynamics: insight from Patagonian fish phylogeography.

Mol Ecol 2008 May 18;17(9):2234-44. Epub 2008 Mar 18.

Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1.

Changes in lake and stream habitats during the growth and retreat of Pleistocene glaciers repeatedly altered the spatial distributions and population sizes of the aquatic fauna of the southern Andes. Here, we use variation in mtDNA control region sequences to infer the temporal dynamics of two species of southern Andean fish during the past few million years. At least five important climate events were associated with major demographic changes: (i) the widespread glaciations of the mid-Pliocene (c. 3.5 Ma); (ii) the largest Patagonian glaciation (1.1 Ma); (iii) the coldest Pleistocene glaciation as indicated by stacked marine delta(18)O (c. 0.7 Ma); (iv) the last southern Patagonian glaciation to reach the Atlantic coast (180 ka); and (v) the last glacial maximum (LGM, 23-25,000 years ago). The colder-water inhabitant, Galaxias platei, underwent a strong bottleneck during the LGM and its haplotype diversity coalesces c. 0.7 Ma. In contrast, the more warm-adapted and widely distributed Percichthys trucha showed continuous growth through the last two glacial cycles but went through an important bottleneck c. 180,000 years ago, at which time populations east of the Andes may have been eliminated. Haplotype diversity of the most divergent P. trucha populations, found west of the Andes, coalesces c. 3.2 Ma. The demographic timelines obtained for the two species thus illustrate the continent-wide response of aquatic life in Patagonia to climate change during the Pleistocene, but also show how differing ecological traits and distributions led to distinctive responses.
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http://dx.doi.org/10.1111/j.1365-294X.2008.03738.xDOI Listing
May 2008

Phylogeography of the Percichthyidae (Pisces) in Patagonia: roles of orogeny, glaciation, and volcanism.

Mol Ecol 2006 Sep;15(10):2949-68

Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada.

We used molecular evidence to examine the roles that vicariance mechanisms (mountain-building and drainage changes during the Pleistocene) have played in producing phylogeographical structure within and among South American fish species of the temperate perch family Percichthyidae. The percichthyids include two South American genera, Percichthys and Percilia, each containing several species, all of which are endemic to southern Argentina and Chile (Patagonia). Maximum-likelihood phylogenies constructed using mitochondrial DNA (mtDNA) control region haplotypes and nuclear GnRH3-2 intron allele sequences support the current taxonomy at the genus level (both Percichthys and Percilia form strongly supported, monophyletic clades) but indicate that species-level designations need revision. Phylogeographical patterns at the mtDNA support the hypothesis that the Andes have been a major barrier to gene flow. Most species diversity occurs in watersheds to the west of the Andes, together with some ancient divergences among conspecific populations. In contrast, only one species (Percichthys trucha) is found east of the Andes, and little to no phylogeographical structure occurs among populations in this region. Mismatch analyses of mtDNA sequences suggest that eastern populations last went through a major bottleneck c. 188 000 bp, a date consistent with the onset of the penultimate and largest Pleistocene glaciation in Patagonia. We suggest that eastern populations have undergone repeated founder-flush events as a consequence of glacial cycles, and that the shallow phylogeny is due to mixing during recolonization periods. The area of greater diversity west of the Andes lies outside the northern limit of the glaciers. mtDNA mismatch analysis of the genus Percilia which is restricted to this area suggests a long-established population at equilibrium. We conclude that patterns of genetic diversity in these South American genera have been primarily influenced by barriers to gene flow (Andean orogeny, and to a lesser extent, isolation in river drainages), and by glacial cycles, which have resulted in population contraction, re-arrangement of some watersheds, and the temporary breakdown of dispersal barriers among eastern river systems.
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http://dx.doi.org/10.1111/j.1365-294X.2006.03010.xDOI Listing
September 2006