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Tracing the trans-pacific evolutionary history of a domesticated Seaweed (Gracilaria chilensis) with archaeological and genetic data.

Guillemin ML, Valero M, Faugeron S, Nelson W, Destombe C - PLoS ONE (2014)

Bottom Line: The history of a domesticated marine macroalga is studied using archaeological, phylogeographic and population genetic tools.Combining archaeological observations with phylogeographic data provided evidence that exchanges between New Zealand and Chile have occurred at least before the Holocene, likely at the end of the Last Glacial Maximum (LGM) and we suggest that migration probably occurred via rafting.Furthermore, the remarkably low microsatellite diversity found in the Chilean populations compared to those in New Zealand is consistent with a recent genetic bottleneck as a result of over-exploitation of natural populations and/or the process of domestication.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia, Chile; CNRS, Sorbonne Universit├ęs, UPMC University Paris VI, UMI 3614, Evolutionary Biology and Ecology of Algae, Station Biologique de Roscoff, CS 90074, Place G. Tessier, 296888 Roscoff, France.

ABSTRACT
The history of a domesticated marine macroalga is studied using archaeological, phylogeographic and population genetic tools. Phylogeographic and population genetic analyses demonstrated that the cultivated red alga Gracilaria chilensis colonised the Chilean coast from New Zealand. Combining archaeological observations with phylogeographic data provided evidence that exchanges between New Zealand and Chile have occurred at least before the Holocene, likely at the end of the Last Glacial Maximum (LGM) and we suggest that migration probably occurred via rafting. Furthermore, the remarkably low microsatellite diversity found in the Chilean populations compared to those in New Zealand is consistent with a recent genetic bottleneck as a result of over-exploitation of natural populations and/or the process of domestication. Therefore, the aquaculture of this seaweed, based essentially on clonal propagation, is occurring from genetically depressed populations and may be driving the species to an extinction vortex in Chile.

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Number of alleles observed in each of the 10 allele frequency classes defined in New Zealand and Chilean populations (pooled data from each side of the South Pacific coast).Reduced number of low frequency alleles is characteristic of a bottleneck [47].
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pone-0114039-g003: Number of alleles observed in each of the 10 allele frequency classes defined in New Zealand and Chilean populations (pooled data from each side of the South Pacific coast).Reduced number of low frequency alleles is characteristic of a bottleneck [47].

Mentions: We found evidence of a bottleneck in Chile where rare alleles (alleles with frequency <5%) were 10 times less common than in New Zealand (Figure 3). New Zealand populations as a whole were near mutation drift equilibrium as revealed by the distribution of allele frequency following the characteristic L-shaped distribution (Figure 3). The distribution of allele frequencies in Chile clearly differed from New Zealand even if it did not exactly fit the mode-shifted distribution described by Luikart et al. [41]. However, when the analysis was carried out on each population separately, half of the Chilean populations showed a clear mode-shifted distribution of allele frequencies (5 of the 11 sampled, CH-LEN, CH-NIE, CH-MET, CH-MAU and CH-RMA) while all populations from New Zealand had an L-shaped distribution. Detection of old population bottlenecks is difficult [47], and the possibility that the Chilean bottleneck was not recent enough (>20 generations) could explain the existence of a non-characteristic mode-shifted distribution of allele frequencies.


Tracing the trans-pacific evolutionary history of a domesticated Seaweed (Gracilaria chilensis) with archaeological and genetic data.

Guillemin ML, Valero M, Faugeron S, Nelson W, Destombe C - PLoS ONE (2014)

Number of alleles observed in each of the 10 allele frequency classes defined in New Zealand and Chilean populations (pooled data from each side of the South Pacific coast).Reduced number of low frequency alleles is characteristic of a bottleneck [47].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263469&req=5

pone-0114039-g003: Number of alleles observed in each of the 10 allele frequency classes defined in New Zealand and Chilean populations (pooled data from each side of the South Pacific coast).Reduced number of low frequency alleles is characteristic of a bottleneck [47].
Mentions: We found evidence of a bottleneck in Chile where rare alleles (alleles with frequency <5%) were 10 times less common than in New Zealand (Figure 3). New Zealand populations as a whole were near mutation drift equilibrium as revealed by the distribution of allele frequency following the characteristic L-shaped distribution (Figure 3). The distribution of allele frequencies in Chile clearly differed from New Zealand even if it did not exactly fit the mode-shifted distribution described by Luikart et al. [41]. However, when the analysis was carried out on each population separately, half of the Chilean populations showed a clear mode-shifted distribution of allele frequencies (5 of the 11 sampled, CH-LEN, CH-NIE, CH-MET, CH-MAU and CH-RMA) while all populations from New Zealand had an L-shaped distribution. Detection of old population bottlenecks is difficult [47], and the possibility that the Chilean bottleneck was not recent enough (>20 generations) could explain the existence of a non-characteristic mode-shifted distribution of allele frequencies.

Bottom Line: The history of a domesticated marine macroalga is studied using archaeological, phylogeographic and population genetic tools.Combining archaeological observations with phylogeographic data provided evidence that exchanges between New Zealand and Chile have occurred at least before the Holocene, likely at the end of the Last Glacial Maximum (LGM) and we suggest that migration probably occurred via rafting.Furthermore, the remarkably low microsatellite diversity found in the Chilean populations compared to those in New Zealand is consistent with a recent genetic bottleneck as a result of over-exploitation of natural populations and/or the process of domestication.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia, Chile; CNRS, Sorbonne Universit├ęs, UPMC University Paris VI, UMI 3614, Evolutionary Biology and Ecology of Algae, Station Biologique de Roscoff, CS 90074, Place G. Tessier, 296888 Roscoff, France.

ABSTRACT
The history of a domesticated marine macroalga is studied using archaeological, phylogeographic and population genetic tools. Phylogeographic and population genetic analyses demonstrated that the cultivated red alga Gracilaria chilensis colonised the Chilean coast from New Zealand. Combining archaeological observations with phylogeographic data provided evidence that exchanges between New Zealand and Chile have occurred at least before the Holocene, likely at the end of the Last Glacial Maximum (LGM) and we suggest that migration probably occurred via rafting. Furthermore, the remarkably low microsatellite diversity found in the Chilean populations compared to those in New Zealand is consistent with a recent genetic bottleneck as a result of over-exploitation of natural populations and/or the process of domestication. Therefore, the aquaculture of this seaweed, based essentially on clonal propagation, is occurring from genetically depressed populations and may be driving the species to an extinction vortex in Chile.

Show MeSH
Related in: MedlinePlus