Integrating morphological and genetic data at different spatial scales in a cosmopolitan marine turtle species: challenges for management and conservation

Abstract Patterns of genetic structure in highly mobile marine vertebrates may be accompanied by phenotypic variation. Most studies in marine turtles focused on population genetic structure have been performed at rookeries. We studied whether genetic and morphological variation of the endangered green turtle (Chelonia mydas) is consistent geographically, focusing on foraging grounds. An association between population genetic structure and body shape variation at broad (inter-lineage) and fine (foraging grounds) scales was predicted and analysed using mitochondrial DNA and geometric morphometrics. Although genetic and phenotypic differentiation patterns were congruent between lineages, no fine-scale association was found, suggesting adaptive divergence. Connectivity among Pacific foraging grounds found here suggests that temperatures of ocean surface currents may influence the genetic structure of C. mydas on a broad scale. Our results suggest that vicariance, dispersal, life-history traits and ecological conditions operating in foraging grounds have shaped the intraspecific morphology and genetic diversity of this species. Considering a range of geographic and temporal scales is useful when management strategies are required for cosmopolitan species. Integrating morphological and genetic tools at different spatial scales, conservation management is proposed based on protection of neutral and adaptive diversity. This approach opens new questions and challenges, especially regarding conservation genetics in cosmopolitan species.

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Significant genetic differences among Heterodera schachtii populations within and among sugar beet production areas

Nematology ◽

10.1163/15685411-00003297 ◽

2020 ◽

Vol 22 (2) ◽

pp. 165-177 ◽

Cited By ~ 1

Author(s):

Rasha Haj Nuaima ◽

Johannes Roeb ◽

Johannes Hallmann ◽

Matthias Daub ◽

Holger Heuer

Keyword(s):

Genetic Variation ◽

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Spatial Scales ◽

Geographic Distance ◽

Heterodera Schachtii ◽

Parasitic Nematodes ◽

Neutral Genetic Variation ◽

Production Areas

Summary Characterising the non-neutral genetic variation within and among populations of plant-parasitic nematodes is essential to determine factors shaping the population genetic structure. This study describes the genetic variation of the parasitism gene vap1 within and among geographic populations of the beet cyst nematode Heterodera schachtii. Forty populations of H. schachtii were sampled at four spatial scales: 695 km, 49 km, 3.1 km and 0.24 km. DGGE fingerprinting showed significant differences in vap1 patterns among populations. High similarity of vap1 patterns appeared between geographically close populations, and occasionally among distant populations. Analysis of spatially sampled populations within fields revealed an effect of tillage direction on the vap1 similarity for two of four studied fields. Overall, geographic distance and similarity of vap1 patterns of H. schachtii populations were negatively correlated. In conclusion, the population genetic structure was shaped by the interplay between the genetic adaptation and the passive transport of this nematode.

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Birds are islands for parasites

Biology Letters ◽

10.1098/rsbl.2014.0255 ◽

2014 ◽

Vol 10 (8) ◽

pp. 20140255 ◽

Cited By ~ 25

Author(s):

Jennifer A. H. Koop ◽

Karen E. DeMatteo ◽

Patricia G. Parker ◽

Noah K. Whiteman

Keyword(s):

Population Structure ◽

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Evolutionary Biology ◽

Isolation By Distance ◽

Spatial Scales ◽

Island Populations ◽

Louse Species ◽

Parasite Populations

Understanding the mechanisms driving the extraordinary diversification of parasites is a major challenge in evolutionary biology. Co-speciation, one proposed mechanism that could contribute to this diversity is hypothesized to result from allopatric co-divergence of host–parasite populations. We found that island populations of the Galápagos hawk ( Buteo galapagoensis ) and a parasitic feather louse species ( Degeeriella regalis ) exhibit patterns of co-divergence across variable temporal and spatial scales. Hawks and lice showed nearly identical population genetic structure across the Galápagos Islands. Hawk population genetic structure is explained by isolation by distance among islands. Louse population structure is best explained by hawk population structure, rather than isolation by distance per se , suggesting that lice tightly track the recent population histories of their hosts. Among hawk individuals, louse populations were also highly structured, suggesting that hosts serve as islands for parasites from an evolutionary perspective. Altogether, we found that host and parasite populations may have responded in the same manner to geographical isolation across spatial scales. Allopatric co-divergence is likely one important mechanism driving the diversification of parasites.

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Population genetic structure of the tree-hole tick Ixodes arboricola (Acari: Ixodidae) at different spatial scales

Heredity ◽

10.1038/hdy.2014.41 ◽

2014 ◽

Vol 113 (5) ◽

pp. 408-415 ◽

Cited By ~ 8

Author(s):

A R Van Oosten ◽

D J A Heylen ◽

K Jordaens ◽

T Backeljau ◽

E Matthysen

Keyword(s):

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Spatial Scales ◽

Tree Hole ◽

Ixodes Arboricola

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Population genetic structure of three freshwater mussel (Unionidae) species within a small stream system: significant variation at local spatial scales

Freshwater Biology ◽

10.1111/j.1365-2427.2007.01756.x ◽

2007 ◽

Vol 52 (8) ◽

pp. 1427-1439 ◽

Cited By ~ 28

Author(s):

DAVID J. BERG ◽

ALAN D. CHRISTIAN ◽

SHELDON I. GUTTMAN

Keyword(s):

Genetic Structure ◽

Population Genetic Structure ◽

Significant Variation ◽

Population Genetic ◽

Spatial Scales ◽

Freshwater Mussel ◽

Small Stream ◽

Stream System

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A tale of two seas: contrasting patterns of population structure in the small-spotted catshark across Europe

Royal Society Open Science ◽

10.1098/rsos.140175 ◽

2014 ◽

Vol 1 (3) ◽

pp. 140175 ◽

Cited By ~ 13

Author(s):

Chrysoula Gubili ◽

David W. Sims ◽

Ana Veríssimo ◽

Paolo Domenici ◽

Jim Ellis ◽

...

Keyword(s):

Population Structure ◽

Genetic Structure ◽

Population Genetic Structure ◽

Population Genetic ◽

Spatial Scales ◽

Sea Level Changes ◽

Glacial Cycles ◽

Mediterranean Populations ◽

Population Reduction ◽

The Mediterranean

Elasmobranchs represent important components of marine ecosystems, but they can be vulnerable to overexploitation. This has driven investigations into the population genetic structure of large-bodied pelagic sharks, but relatively little is known of population structure in smaller demersal taxa, which are perhaps more representative of the biodiversity of the group. This study explores spatial population genetic structure of the small-spotted catshark ( Scyliorhinus canicula ), across European seas. The results show significant genetic differences among most of the Mediterranean sample collections, but no significant structure among Atlantic shelf areas. The data suggest the Mediterranean populations are likely to have persisted in a stable and structured environment during Pleistocene sea-level changes. Conversely, the Northeast Atlantic populations would have experienced major changes in habitat availability during glacial cycles, driving patterns of population reduction and expansion. The data also provide evidence of male-biased dispersal and female philopatry over large spatial scales, implying complex sex-determined differences in the behaviour of elasmobranchs. On the basis of this evidence, we suggest that patterns of connectivity are determined by trends of past habitat stability that provides opportunity for local adaptation in species exhibiting philopatric behaviour, implying that resilience of populations to fisheries and other stressors may differ across the range of species.

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Population genetic structure of Indo-West Pacific carcharhinid sharks: what do we know and where to from here?

Pacific Conservation Biology ◽

10.1071/pc19046 ◽

2020 ◽

Vol 26 (4) ◽

pp. 319

Author(s):

Brenton M. Pember ◽

Jennifer A. Chaplin ◽

Neil R. Loneragan ◽

Matias Braccini

Keyword(s):

Genetic Structure ◽

Dna Sequences ◽

Population Genetic Structure ◽

Population Genetic ◽

Population Genomics ◽

Spatial Scales ◽

Small Sample ◽

Future Research ◽

Individual Species ◽

West Pacific

The Carcharhinidae is one of the most at-risk shark families in the Indo-West Pacific (IWP), which is a global priority for the conservation of elasmobranchs. Of the 57 described species of carcharhinids, 43 are known from the IWP, where many are subject to high fishing pressure. Many of these species are also found outside this bioregion. Understanding the connectivity of individual species across their ranges is paramount to successful management of their fisheries. Studies of population genetic structure have been the mainstay for assessing connectivity. Here, we review 41 studies pertaining to the population genetic structure of 20 species of carcharhinid whose ranges include the IWP and for which relevant data are available. The genetic markers used range from microsatellite loci and small mitochondrial DNA sequences (375 to 4797bp) to genomic analyses. Overall, the population genetic structure for these carcharhinids was varied but patterns emerged according to the lifestyle of the species, with the greatest structure shown by species that are highly habitat dependent and the least structure shown by oceanic species. Experimental designs of the underlying studies have, however, often been opportunistic with small sample sizes, few locations sampled and based on analysis of single mitochondrial regions and/or few microsatellite markers. The literature provides a basis for understanding the population genetic structure of IWP carcharhinids, but future research needs to focus on the application of population genomics and more robust experimental design so that population genetic structure can be quantified with higher certainty and resolution over finer spatial scales.

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