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Population Genetics of Franciscana Dolphins (Pontoporia blainvillei): Introducing a New Population from the Southern Edge of Their Distribution.

Gariboldi MC, Túnez JI, Dejean CB, Failla M, Vitullo AD, Negri MF, Cappozzo HL - PLoS ONE (2015)

Bottom Line: From the analysis of mitochondrial DNA control region sequences, 5 novel haplotypes were found, totalizing 60 haplotypes for the entire distribution range.The haplotype network did not show an apparent phylogeographical signal for the southern FMAs.The apparent increase in NC+CL+RN size would be consistent with the higher genetic variability found, since genetic diversity is generally higher in older and expanding populations.

View Article: PubMed Central - PubMed

Affiliation: Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.

ABSTRACT
Due to anthropogenic factors, the franciscana dolphin, Pontoporia blainvillei, is the most threatened small cetacean on the Atlantic coast of South America. Four Franciscana Management Areas have been proposed: Espiritu Santo to Rio de Janeiro (FMA I), São Paulo to Santa Catarina (FMA II), Rio Grande do Sul to Uruguay (FMA III), and Argentina (FMA IV). Further genetic studies distinguished additional populations within these FMAs. We analyzed the population structure, phylogeography, and demographic history in the southernmost portion of the species range. From the analysis of mitochondrial DNA control region sequences, 5 novel haplotypes were found, totalizing 60 haplotypes for the entire distribution range. The haplotype network did not show an apparent phylogeographical signal for the southern FMAs. Two populations were identified: Monte Hermoso (MH) and Necochea (NC)+Claromecó (CL)+Río Negro (RN). The low levels of genetic variability, the relative constant size over time, and the low levels of gene flow may indicate that MH has been colonized by a few maternal lineages and became isolated from geographically close populations. The apparent increase in NC+CL+RN size would be consistent with the higher genetic variability found, since genetic diversity is generally higher in older and expanding populations. Additionally, RN may have experienced a recent split from CL and NC; current high levels of gene flow may be occurring between the latter ones. FMA IV would comprise four franciscana dolphin populations: Samborombón West+Samborombón South, Cabo San Antonio+Buenos Aires East, NC+CL+Buenos Aires Southwest+RN and MH. Results achieved in this study need to be taken into account in order to ensure the long-term survival of the species.

No MeSH data available.


Franciscana Management Areas (FMAs) and sampled sites.Previously proposed FMAs (FMA I-VI) [24] are delineated with solid lines. The number of samples is shown between brackets. ES: Espíritu Santo; RJ: Rio de Janeiro; SP: São Paulo; PR: Paraná; SCA: Santa Catarina; RG: Rio Grande do Sul; SCL: San Clemente del Tuyú; PN: Pinamar; NC: Necochea; CL: Claromecó; MH: Monte Hermoso; BB: Bahía Blanca; RN: Río Negro. Note: Sample size for CL (N = 51) corresponds to 31 samples from Lázaro et al. [5] and 20 samples from this study.
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pone.0132854.g001: Franciscana Management Areas (FMAs) and sampled sites.Previously proposed FMAs (FMA I-VI) [24] are delineated with solid lines. The number of samples is shown between brackets. ES: Espíritu Santo; RJ: Rio de Janeiro; SP: São Paulo; PR: Paraná; SCA: Santa Catarina; RG: Rio Grande do Sul; SCL: San Clemente del Tuyú; PN: Pinamar; NC: Necochea; CL: Claromecó; MH: Monte Hermoso; BB: Bahía Blanca; RN: Río Negro. Note: Sample size for CL (N = 51) corresponds to 31 samples from Lázaro et al. [5] and 20 samples from this study.

Mentions: Based on the species geographic distribution, contaminant and parasite loads, vital rates, and phenotype and genotype information available at that time, Secchi et al. [24] divided the species distribution range into four different segments called Franciscana Management Areas (FMAs): FMA I ranges from ES to Rio de Janeiro (RJ), FMA II from São Paulo (SP) to Santa Catarina (SCA), FMA III from Rio Grande do Sul (RG) to Uruguay (UY), whereas FMA IV includes the coasts of Buenos Aires and Río Negro (RN) in Argentina (Fig 1). Subsequently, studies based on mitochondrial DNA (mtDNA) analyses [3,5,30–32] confirmed Secchi’s subdivision and recognized the existence of San Clemente del Tuyú (SCL) [3], Argentina, as a genetically differentiated population. Additionally, Mendez et al. [33], performed genetic analyses including mtDNA and microsatellite information, suggesting the existence of 3 population within Argentina: Samborombón West (SW)/Samborombón South (SS), which includes SCL location; Cabo San Antonio (CSA)/Buenos Aires East (BAE); and Buenos Aires South (BAS)/Buenos Aires Southwest (BASW), which includes Claromecó (CL) location. However, although in Mendez et al. [3] no genetic differences were found between CSA and UY, Mendez et al. [33] did not compare CSA/BAE and UY. Based on this information, at least five genetic populations of franciscana dolphins have been distinguished: RJ, SP-Parana (PR); RG-UY, SW/SS and BAS/BASW; and a probable sixth population would be found in CSA/BAE. More recently, Cuhna et al. [34] performed a new genetic study in which they included sequences of franciscana dolphins from the northern limit of its range and re-assessed Secchi et al. [24] FMAs. They found additional genetically distinct populations in Brazil and an evolutionary break between franciscanas from the northern (ES to North RJ) and the southern (South RJ to Argentina) portions of its distribution, which indicate that they should be managed as independent Evolutionarily Significant Units. Additionally, Valsecchi & Zanelatto [32] found that the population from RJ, at the northern limit of the species distribution, showed the lowest genetic variability and suggested the analysis of this phenomenon in the southern populations of franciscana. Following Valsecchi & Zanelatto [32] suggestion, Negri [31] performed genetic analyses on 44 franciscana dolphins collected along the coastal area between Necochea (NC) and Bahía Blanca (BB), Argentina. However, the authors did not include in its analysis the population of franciscanas located off the coasts of RN, which includes the southernmost breeding area reported to date [35], providing only partial information about the southern populations of the species.


Population Genetics of Franciscana Dolphins (Pontoporia blainvillei): Introducing a New Population from the Southern Edge of Their Distribution.

Gariboldi MC, Túnez JI, Dejean CB, Failla M, Vitullo AD, Negri MF, Cappozzo HL - PLoS ONE (2015)

Franciscana Management Areas (FMAs) and sampled sites.Previously proposed FMAs (FMA I-VI) [24] are delineated with solid lines. The number of samples is shown between brackets. ES: Espíritu Santo; RJ: Rio de Janeiro; SP: São Paulo; PR: Paraná; SCA: Santa Catarina; RG: Rio Grande do Sul; SCL: San Clemente del Tuyú; PN: Pinamar; NC: Necochea; CL: Claromecó; MH: Monte Hermoso; BB: Bahía Blanca; RN: Río Negro. Note: Sample size for CL (N = 51) corresponds to 31 samples from Lázaro et al. [5] and 20 samples from this study.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4519281&req=5

pone.0132854.g001: Franciscana Management Areas (FMAs) and sampled sites.Previously proposed FMAs (FMA I-VI) [24] are delineated with solid lines. The number of samples is shown between brackets. ES: Espíritu Santo; RJ: Rio de Janeiro; SP: São Paulo; PR: Paraná; SCA: Santa Catarina; RG: Rio Grande do Sul; SCL: San Clemente del Tuyú; PN: Pinamar; NC: Necochea; CL: Claromecó; MH: Monte Hermoso; BB: Bahía Blanca; RN: Río Negro. Note: Sample size for CL (N = 51) corresponds to 31 samples from Lázaro et al. [5] and 20 samples from this study.
Mentions: Based on the species geographic distribution, contaminant and parasite loads, vital rates, and phenotype and genotype information available at that time, Secchi et al. [24] divided the species distribution range into four different segments called Franciscana Management Areas (FMAs): FMA I ranges from ES to Rio de Janeiro (RJ), FMA II from São Paulo (SP) to Santa Catarina (SCA), FMA III from Rio Grande do Sul (RG) to Uruguay (UY), whereas FMA IV includes the coasts of Buenos Aires and Río Negro (RN) in Argentina (Fig 1). Subsequently, studies based on mitochondrial DNA (mtDNA) analyses [3,5,30–32] confirmed Secchi’s subdivision and recognized the existence of San Clemente del Tuyú (SCL) [3], Argentina, as a genetically differentiated population. Additionally, Mendez et al. [33], performed genetic analyses including mtDNA and microsatellite information, suggesting the existence of 3 population within Argentina: Samborombón West (SW)/Samborombón South (SS), which includes SCL location; Cabo San Antonio (CSA)/Buenos Aires East (BAE); and Buenos Aires South (BAS)/Buenos Aires Southwest (BASW), which includes Claromecó (CL) location. However, although in Mendez et al. [3] no genetic differences were found between CSA and UY, Mendez et al. [33] did not compare CSA/BAE and UY. Based on this information, at least five genetic populations of franciscana dolphins have been distinguished: RJ, SP-Parana (PR); RG-UY, SW/SS and BAS/BASW; and a probable sixth population would be found in CSA/BAE. More recently, Cuhna et al. [34] performed a new genetic study in which they included sequences of franciscana dolphins from the northern limit of its range and re-assessed Secchi et al. [24] FMAs. They found additional genetically distinct populations in Brazil and an evolutionary break between franciscanas from the northern (ES to North RJ) and the southern (South RJ to Argentina) portions of its distribution, which indicate that they should be managed as independent Evolutionarily Significant Units. Additionally, Valsecchi & Zanelatto [32] found that the population from RJ, at the northern limit of the species distribution, showed the lowest genetic variability and suggested the analysis of this phenomenon in the southern populations of franciscana. Following Valsecchi & Zanelatto [32] suggestion, Negri [31] performed genetic analyses on 44 franciscana dolphins collected along the coastal area between Necochea (NC) and Bahía Blanca (BB), Argentina. However, the authors did not include in its analysis the population of franciscanas located off the coasts of RN, which includes the southernmost breeding area reported to date [35], providing only partial information about the southern populations of the species.

Bottom Line: From the analysis of mitochondrial DNA control region sequences, 5 novel haplotypes were found, totalizing 60 haplotypes for the entire distribution range.The haplotype network did not show an apparent phylogeographical signal for the southern FMAs.The apparent increase in NC+CL+RN size would be consistent with the higher genetic variability found, since genetic diversity is generally higher in older and expanding populations.

View Article: PubMed Central - PubMed

Affiliation: Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.

ABSTRACT
Due to anthropogenic factors, the franciscana dolphin, Pontoporia blainvillei, is the most threatened small cetacean on the Atlantic coast of South America. Four Franciscana Management Areas have been proposed: Espiritu Santo to Rio de Janeiro (FMA I), São Paulo to Santa Catarina (FMA II), Rio Grande do Sul to Uruguay (FMA III), and Argentina (FMA IV). Further genetic studies distinguished additional populations within these FMAs. We analyzed the population structure, phylogeography, and demographic history in the southernmost portion of the species range. From the analysis of mitochondrial DNA control region sequences, 5 novel haplotypes were found, totalizing 60 haplotypes for the entire distribution range. The haplotype network did not show an apparent phylogeographical signal for the southern FMAs. Two populations were identified: Monte Hermoso (MH) and Necochea (NC)+Claromecó (CL)+Río Negro (RN). The low levels of genetic variability, the relative constant size over time, and the low levels of gene flow may indicate that MH has been colonized by a few maternal lineages and became isolated from geographically close populations. The apparent increase in NC+CL+RN size would be consistent with the higher genetic variability found, since genetic diversity is generally higher in older and expanding populations. Additionally, RN may have experienced a recent split from CL and NC; current high levels of gene flow may be occurring between the latter ones. FMA IV would comprise four franciscana dolphin populations: Samborombón West+Samborombón South, Cabo San Antonio+Buenos Aires East, NC+CL+Buenos Aires Southwest+RN and MH. Results achieved in this study need to be taken into account in order to ensure the long-term survival of the species.

No MeSH data available.