Limits...
Genetic models reveal historical patterns of sea lamprey population fluctuations within Lake Champlain.

D'Aloia CC, Azodi CB, Sheldon SP, Trombulak SC, Ardren WR - PeerJ (2015)

Bottom Line: Coalescent models based on mtDNA and nDNA identified two potential demographic events: a population decline followed by a very recent population expansion.The decline in effective population size may correlate with land-use and fishing pressure changes post-European settlement, while the recent expansion may be associated with the implementation of the salmonid stocking program in the 1970s.These results are most consistent with the hypothesis that sea lamprey are native to Lake Champlain; however, the credibility intervals around parameter estimates demonstrate that there is uncertainty regarding the magnitude and timing of past demographic events.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Ecology & Evolutionary Biology, University of Toronto , Toronto, Ontario , Canada ; Department of Biology, Middlebury College , Middlebury, VT , USA.

ABSTRACT
The origin of sea lamprey (Petromyzon marinus) in Lake Champlain has been heavily debated over the past decade. Given the lack of historical documentation, two competing hypotheses have emerged in the literature. First, it has been argued that the relatively recent population size increase and concomitant rise in wounding rates on prey populations are indicative of an invasive population that entered the lake through the Champlain Canal. Second, recent genetic evidence suggests a post-glacial colonization at the end of the Pleistocene, approximately 11,000 years ago. One limitation to resolving the origin of sea lamprey in Lake Champlain is a lack of historical and current measures of population size. In this study, the issue of population size was explicitly addressed using nuclear (nDNA) and mitochondrial DNA (mtDNA) markers to estimate historical demography with genetic models. Haplotype network analysis, mismatch analysis, and summary statistics based on mtDNA noncoding sequences for NCI (479 bp) and NCII (173 bp) all indicate a recent population expansion. Coalescent models based on mtDNA and nDNA identified two potential demographic events: a population decline followed by a very recent population expansion. The decline in effective population size may correlate with land-use and fishing pressure changes post-European settlement, while the recent expansion may be associated with the implementation of the salmonid stocking program in the 1970s. These results are most consistent with the hypothesis that sea lamprey are native to Lake Champlain; however, the credibility intervals around parameter estimates demonstrate that there is uncertainty regarding the magnitude and timing of past demographic events.

No MeSH data available.


Haplotype network for 14 concatenated mtDNA haplotypes found in Lake Champlain, constructed using TCS v1.2.1 with 95% parsimony.The size of the circle is proportional to the relative abundance of the haplotype. Solid lines represent one point mutation and small, unfilled circles represent inferred haplotypes. The mutations resulting in branching off of haplotype 7 are concentrated in the repetitive region of the NCII 3′ region, which has an elevated mutation rate due to strand slippage.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4631463&req=5

fig-1: Haplotype network for 14 concatenated mtDNA haplotypes found in Lake Champlain, constructed using TCS v1.2.1 with 95% parsimony.The size of the circle is proportional to the relative abundance of the haplotype. Solid lines represent one point mutation and small, unfilled circles represent inferred haplotypes. The mutations resulting in branching off of haplotype 7 are concentrated in the repetitive region of the NCII 3′ region, which has an elevated mutation rate due to strand slippage.

Mentions: We observed 14 unique haplotypes among the 54 NCTotal mitochondrial sequences (Table 1). The haplotype network of all 14 NCtotal haplotypes visualizes their relationships as well as their relative abundance (Fig. 1). Haplotype 1 is predominant in Lake Champlain, with five other rare haplotypes (2, 3, 6, 7, and 9) having only one base pair difference from haplotype 1. Most of the mutations within these five haplotypes are point mutations within NCI or the 5′ end of NCII (Table 1). In contrast, most of the remaining rare haplotypes branch off of haplotype 7 and are characterized by mutations within the A/T-rich, repetitive 3′ region of NCII. In general, these mutations in the repetitive region were retained in each subsequent repeat of the sequence, leading to a larger number of overall mutations in NCII.


Genetic models reveal historical patterns of sea lamprey population fluctuations within Lake Champlain.

D'Aloia CC, Azodi CB, Sheldon SP, Trombulak SC, Ardren WR - PeerJ (2015)

Haplotype network for 14 concatenated mtDNA haplotypes found in Lake Champlain, constructed using TCS v1.2.1 with 95% parsimony.The size of the circle is proportional to the relative abundance of the haplotype. Solid lines represent one point mutation and small, unfilled circles represent inferred haplotypes. The mutations resulting in branching off of haplotype 7 are concentrated in the repetitive region of the NCII 3′ region, which has an elevated mutation rate due to strand slippage.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4631463&req=5

fig-1: Haplotype network for 14 concatenated mtDNA haplotypes found in Lake Champlain, constructed using TCS v1.2.1 with 95% parsimony.The size of the circle is proportional to the relative abundance of the haplotype. Solid lines represent one point mutation and small, unfilled circles represent inferred haplotypes. The mutations resulting in branching off of haplotype 7 are concentrated in the repetitive region of the NCII 3′ region, which has an elevated mutation rate due to strand slippage.
Mentions: We observed 14 unique haplotypes among the 54 NCTotal mitochondrial sequences (Table 1). The haplotype network of all 14 NCtotal haplotypes visualizes their relationships as well as their relative abundance (Fig. 1). Haplotype 1 is predominant in Lake Champlain, with five other rare haplotypes (2, 3, 6, 7, and 9) having only one base pair difference from haplotype 1. Most of the mutations within these five haplotypes are point mutations within NCI or the 5′ end of NCII (Table 1). In contrast, most of the remaining rare haplotypes branch off of haplotype 7 and are characterized by mutations within the A/T-rich, repetitive 3′ region of NCII. In general, these mutations in the repetitive region were retained in each subsequent repeat of the sequence, leading to a larger number of overall mutations in NCII.

Bottom Line: Coalescent models based on mtDNA and nDNA identified two potential demographic events: a population decline followed by a very recent population expansion.The decline in effective population size may correlate with land-use and fishing pressure changes post-European settlement, while the recent expansion may be associated with the implementation of the salmonid stocking program in the 1970s.These results are most consistent with the hypothesis that sea lamprey are native to Lake Champlain; however, the credibility intervals around parameter estimates demonstrate that there is uncertainty regarding the magnitude and timing of past demographic events.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Ecology & Evolutionary Biology, University of Toronto , Toronto, Ontario , Canada ; Department of Biology, Middlebury College , Middlebury, VT , USA.

ABSTRACT
The origin of sea lamprey (Petromyzon marinus) in Lake Champlain has been heavily debated over the past decade. Given the lack of historical documentation, two competing hypotheses have emerged in the literature. First, it has been argued that the relatively recent population size increase and concomitant rise in wounding rates on prey populations are indicative of an invasive population that entered the lake through the Champlain Canal. Second, recent genetic evidence suggests a post-glacial colonization at the end of the Pleistocene, approximately 11,000 years ago. One limitation to resolving the origin of sea lamprey in Lake Champlain is a lack of historical and current measures of population size. In this study, the issue of population size was explicitly addressed using nuclear (nDNA) and mitochondrial DNA (mtDNA) markers to estimate historical demography with genetic models. Haplotype network analysis, mismatch analysis, and summary statistics based on mtDNA noncoding sequences for NCI (479 bp) and NCII (173 bp) all indicate a recent population expansion. Coalescent models based on mtDNA and nDNA identified two potential demographic events: a population decline followed by a very recent population expansion. The decline in effective population size may correlate with land-use and fishing pressure changes post-European settlement, while the recent expansion may be associated with the implementation of the salmonid stocking program in the 1970s. These results are most consistent with the hypothesis that sea lamprey are native to Lake Champlain; however, the credibility intervals around parameter estimates demonstrate that there is uncertainty regarding the magnitude and timing of past demographic events.

No MeSH data available.