Global population structure and life history traits in the Galapagos Marine Reserve of wahoo (Acanthocybium solandri): Implications for fisheries management

2019 ◽  
Author(s):  
Maria Haro
Author(s):  
Gaotian Zhang ◽  
Jake D Mostad ◽  
Erik C Andersen

Abstract Life history traits underlie the fitness of organisms and are under strong natural selection. A new mutation that positively impacts a life history trait will likely increase in frequency and become fixed in a population (e.g. a selective sweep). The identification of the beneficial alleles that underlie selective sweeps provides insights into the mechanisms that occurred during the evolution of a species. In the global population of Caenorhabditis elegans, we previously identified selective sweeps that have drastically reduced chromosomal-scale genetic diversity in the species. Here, we measured the fecundity of 121 wild C. elegans strains, including many recently isolated divergent strains from the Hawaiian islands and found that strains with larger swept genomic regions have significantly higher fecundity than strains without evidence of the recent selective sweeps. We used genome-wide association (GWA) mapping to identify three quantitative trait loci (QTL) underlying the fecundity variation. Additionally, we mapped previous fecundity data from wild C. elegans strains and C. elegans recombinant inbred advanced intercross lines that were grown in various conditions and detected eight QTL using GWA and linkage mappings. These QTL show the genetic complexity of fecundity across this species. Moreover, the haplotype structure in each GWA QTL region revealed correlations with recent selective sweeps in the C. elegans population. North American and European strains had significantly higher fecundity than most strains from Hawaii, a hypothesized origin of the C. elegans species, suggesting that beneficial alleles that caused increased fecundity could underlie the selective sweeps during the worldwide expansion of C. elegans.


Author(s):  
Pierre Lesturgie ◽  
Serge Planes ◽  
Stefano Mona

Dispersal abilities play a crucial role in shaping the extent of population genetic structure, with more mobile species being panmictic over large geographic ranges and less mobile ones organized in meta-populations exchanging migrants to different degrees. In turn, population structure directly influences the coalescence pattern of the sampled lineages, but the consequences on the estimated variation of the effective population size (Ne) over time obtained by means of unstructured demographic models remain poorly understood. However, this knowledge is crucial for biologically interpreting the observed Ne trajectory and further devising conservation strategies in endangered species. Here we investigated the demographic history of four shark species (Carharhinus melanopterus, Carharhinus limbatus, Carharhinus amblyrhynchos, Galeocerdo cuvier) with different degrees of endangered status and life history traits related to dispersal distributed in the Indo-Pacific and sampled off New Caledonia. We compared several evolutionary scenarios representing both structured (meta-population) and unstructured models and then inferred the Ne variation through time. By performing extensive coalescent simulations, we provided a general framework relating the underlying population structure and the observed Ne dynamics. On this basis, we concluded that the recent decline observed in three out of the four considered species when assuming unstructured demographic models can be explained by the presence of population structure. Furthermore, we also demonstrated the limits of the inferences based on the sole site frequency spectrum and warn that statistics based on linkage disequilibrium will be needed to exclude recent demographic events affecting meta-populations.


2020 ◽  
Vol 77 (10) ◽  
pp. 1688-1699
Author(s):  
Nan Zheng ◽  
Matthew Robertson ◽  
Noel Cadigan ◽  
Fan Zhang ◽  
Joanne Morgan ◽  
...  

Fisheries management usually does not explicitly account for spatial variation in life history traits within populations. However, for some stocks this spatial variation may be substantial. We develop a spatiotemporal generalized linear model and fit the model to a long time series of maturation data for American plaice (Hippoglossoides platessoides) on the Grand Bank off Newfoundland and Labrador. The spatiotemporal correlation structure improves estimation of small-scale spatiotemporal variation in maturity across locations and times with limited or few samples. We test how American plaice maturity varies at three different spatial resolutions. We find improvements in model fit when decreasing spatial scales for higher spatial resolution due to high levels of spatial heterogeneity in American plaice maturity at age and size. Modeling variation in life history traits at the appropriate spatial and temporal scales is necessary for understanding population dynamics and developing appropriate fisheries management strategies.


Copeia ◽  
2018 ◽  
Vol 106 (3) ◽  
pp. 515-523 ◽  
Author(s):  
J. R. Marin Jarrin ◽  
S. Andrade-Vera ◽  
C. Reyes-Ojedis ◽  
P. Salinas-de-León

Author(s):  
Pierre Lesturgie ◽  
Serge Planes ◽  
Stefano Mona

Dispersal abilities play a crucial role in shaping the extent of population genetic structure, with more mobile species being panmictic over large geographic ranges and less mobile ones organized in meta-populations exchanging migrants to different degrees. In turn, population structure directly influences the coalescent pattern of the sampled lineages, but the consequences on the estimated variation of the effective population size (Ne) over time obtained by means of unstructured demographic models remain poorly understood. However, this knowledge is crucial for biologically interpreting the observed Ne trajectory and further devising conservation strategies in endangered species. Here we investigated the demographic history of four shark species (Carharhinus melanopterus, Carharhinus limbatus, Carharhinus amblyrhynchos, Galeocerdo cuvier) with different degrees of endangered status and life history traits related to dispersal distributed in the Indo-Pacific and sampled off New Caledonia. We compared several evolutionary scenarios representing both structured (meta-population) and unstructured models and then inferred the Ne variation through time. By performing extensive coalescent simulations, we provided a general framework relating the underlying population structure and the observed Ne dynamics. On this basis, we concluded that the recent decline observed in three out of the four considered species when assuming unstructured demographic models can be explained by the presence of population structure. Furthermore, we also demonstrated the limits of the inferences based on the sole site frequency spectrum and warn that statistics based on linkage disequilibrium will be needed to exclude recent demographic events affecting meta-populations.


2017 ◽  
Vol 233 (3) ◽  
pp. 190-205 ◽  
Author(s):  
Jessica A. Gilpin ◽  
Nanette E. Chadwick

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