Genetic structure and phylogeography of freshwater shrimps (Macrobrachium australiense and Macrobrachium tolmerum): the role of contemporary and historical events

2009 ◽  
Vol 60 (6) ◽  
pp. 541 ◽  
Author(s):  
Suman Sharma ◽  
Jane M. Hughes
Keyword(s):  
Gene Flow ◽  
Population Expansion ◽  
Freshwater Species ◽  
River Systems ◽  
Genetic Structuring ◽  
Recent Population Expansion ◽  
Sea Levels ◽  
Coastal Streams ◽  
Limited Dispersal ◽  
Limited Gene Flow

Freshwater species are expected to show higher levels of genetic structuring than those inhabiting estuarine or marine environments because it is difficult for freshwater species to move between river systems. Previous genetic studies of freshwater species from coastal streams in south-east Queensland had proposed that several of these streams had a common confluence relatively recently, when sea levels were lower ~10 000 years bp. The present study was undertaken to test this idea using two freshwater shrimp species, Macrobrachium australiense and Macrobrachium tolmerum. In M. australiense, there was a major phylogeographical break in the middle of the Sunshine Coast region that was expected to be homogeneous because these creeks may have had a shared confluence before entering the sea, possibly because of extremely limited dispersal abilities compounded over many generations. In M. tolmerum, there was evidence of a recent population expansion and also some evidence of limited gene flow between sites. This is explained by recent colonisation of the area and limited gene flow between river systems, despite the ability of this species to survive in brackish water conditions. The present study shows that even species that are taxonomically very close and that co-occur in the same habitats can have vastly different population structures.

scholarly journals Population genetics of Aedes albopictus (Diptera: Culicidae) in its native range in Lao People’s Democratic Republic

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Maysa Tiemi Motoki ◽  
Dina Madera Fonseca ◽  
Elliott Frederic Miot ◽  
Bruna Demari-Silva ◽  
Phoutmany Thammavong ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Aedes Albopictus ◽  
Isolation By Distance ◽  
Genetic Locus ◽  
Lao Pdr ◽  
Phylogenetic Network ◽  
Population Expansion ◽  
Recent Population Expansion ◽  
The Usa

Abstract Background The Asian tiger mosquito, Aedes (Stegomyia) albopictus (Skuse) is an important worldwide invasive species and can be a locally important vector of chikungunya, dengue and, potentially, Zika. This species is native to Southeast Asia where populations thrive in both temperate and tropical climates. A better understanding of the population structure of Ae. albopictus in Lao PDR is very important in order to support the implementation of strategies for diseases prevention and vector control. In the present study, we investigated the genetic variability of Ae. albopictus across a north-south transect in Lao PDR. Methods We used variability in a 1337-bp fragment of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1), to assess the population structure of Ae. albopictus in Lao PDR. For context, we also examined variability at the same genetic locus in samples of Ae. albopictus from Thailand, China, Taiwan, Japan, Singapore, Italy and the USA. Results We observed very high levels of genetic polymorphism with 46 novel haplotypes in Ae. albopictus from 9 localities in Lao PDR and Thailand populations. Significant differences were observed between the Luangnamtha population and other locations in Lao PDR. However, we found no evidence of isolation by distance. There was overall little genetic structure indicating ongoing and frequent gene flow among populations or a recent population expansion. Indeed, the neutrality test supported population expansion in Laotian Ae. albopictus and mismatch distribution analyses showed a lack of low frequency alleles, a pattern often seen in bottlenecked populations. When samples from Lao PDR were analyzed together with samples from Thailand, China, Taiwan, Japan, Singapore, Italy and the USA, phylogenetic network and Bayesian cluster analysis showed that most populations from tropical/subtropical regions are more genetically related to each other, than populations from temperate regions. Similarly, most populations from temperate regions are more genetically related to each other, than those from tropical/subtropical regions. Conclusions Aedes albopictus in Lao PDR are genetically related to populations from tropical/subtropical regions (i.e. Thailand, Singapore, and California and Texas in the USA). The extensive gene flow among locations in Lao PDR indicates that local control is undermined by repeated introductions from untreated sites.

Genetic analyses reveal limited dispersal and recovery potential in the large freshwater crayfish Euastacus armatus from the southern Murray–Darling Basin

2017 ◽  
Vol 68 (2) ◽  
pp. 213 ◽  
Author(s):  
Nick S. Whiterod ◽  
Sylvia Zukowski ◽  
Martin Asmus ◽  
Dean Gilligan ◽  
Adam D. Miller
Keyword(s):  
Gene Flow ◽  
Anthropogenic Impacts ◽  
Population Decline ◽  
Biological Traits ◽  
Freshwater Crayfish ◽  
Freshwater Species ◽  
Genetic Structuring ◽  
Murray Darling Basin ◽  
Murray River ◽  
Dispersal Limitations

Understanding dispersal traits and adaptive potential is critically important when assessing the vulnerability of freshwater species in highly modified ecosystems. The present study investigates the population genetic structure of the Murray crayfish Euastacus armatus in the southern Murray–Darling Basin. This species has suffered significant population declines in sections of the Murray River in recent years, prompting the need for information on natural recruitment processes to help guide conservation. We assessed allele frequencies from 10 polymorphic microsatellite loci across 20 sites encompassing the majority of the species’ range. Low levels of gene flow were observed throughout hydrologically connected waterways, but significant spatial autocorrelation and low migration rate estimates reflect local genetic structuring and dispersal limitations, with home ranges limited to distances <50-km. Significant genetic differentiation of headwater populations upstream of barriers imposed by impoundments were also observed; however, population simulations demonstrate that these patterns likely reflect historical limitations to gene flow rather than contemporary anthropogenic impacts. Dispersal limitations, coupled with its biological traits, suggest that local populations are vulnerable to environmental disturbance with limited potential for natural recolonisation following population decline. We discuss the implications of these findings in the context of managing the recovery of the species.

scholarly journals Limited gene flow and partial isolation phylogeography of Himalayan snowcock Tetraogallus himalayensis based on part mitochondrial D-loop sequences

2011 ◽  
Vol 57 (6) ◽  
pp. 758-767 ◽  
Author(s):  
Xiaoli Wang ◽  
Jiangyong Qu ◽  
Naifa Liu ◽  
Xinkang Bao ◽  
Sen Song
Keyword(s):  
Mitochondrial Dna ◽  
Gene Flow ◽  
Control Region ◽  
Divergence Time ◽  
Population Expansion ◽  
Middle Pleistocene ◽  
Distribution Analysis ◽  
D Loop ◽  
Limited Gene Flow ◽  
Partial Isolation

Abstract Himalayan snowcock Tetraogallus himalayensis are distributed in alpine and subalpine areas in China. We used mitochondrial DNA control-region data to investigate the origin and past demographic change in sixty-seven Himalayan snowcock T. himalayensis. The fragments of 1155 nucleotides from the control region of mitochondrial DNA were sequenced, and 57 polymorphic positions defined 37 haplotypes. A high level of genetic diversity was detected in all populations sampled and may be associated isolation of the mountains and habitat fragmentation and deterioration from Quaternary glaciations. In the phylogenetic tree, all haplotypes grouped into four groups: clade A (Kunlun Mountains clade), clade B (Northern Qinghai-Tibetan Plateau clade), clade C (Tianshan Mountains clade) and clade D (Kalakunlun Mountains clade). We found a low level of gene flow and significant genetic differentiation among all populations. Based on divergence time we suggest that the divergence of Himalayan snowcock occurred in the middle Pleistocene inter-glaciation, and expansion occurred in the glaciation. Analysis of mtDNA D-loop sequences confirmed demographic population expansion, as did our non-significant mismatch distribution analysis. In conclusion, limited gene flow and a pattern of partial isolation phylogeographic was found in geographic populations of T. himalayansis based on the analysis on mtDNA D-loop sequences.

scholarly journals Isolation of Metrosideros (ʻOhiʻa) Taxa on Oʻahu Increases with Elevation and Extreme Environments

2019 ◽  
Vol 111 (1) ◽  
pp. 103-118 ◽  
Author(s):  
Elizabeth A Stacy ◽  
Tomoko Sakishima ◽  
Heaven Tharp ◽  
Neil Snow
Keyword(s):  
Gene Flow ◽  
Isolation By Distance ◽  
Extreme Environments ◽  
Common Garden ◽  
Metrosideros Polymorpha ◽  
Elevation Gradients ◽  
Principal Role ◽  
Generation Times ◽  
Limited Dispersal ◽  
Limited Gene Flow

Abstract Species radiations should be facilitated by short generation times and limited dispersal among discontinuous populations. Hawaii’s hyper-diverse, landscape-dominant tree, Metrosideros, is unique among the islands’ radiations for its massive populations that occur continuously over space and time within islands, its exceptional capacity for gene flow by both pollen and seed, and its extended life span (ca. &gt;650 years). Metrosideros shows the greatest phenotypic and microsatellite DNA diversity on Oʻahu, where taxa occur in tight sympatry or parapatry in mesic and montane wet forest on 2 volcanoes. We document the nonrandom distributions of 12 taxa (including unnamed morphotypes) along elevation gradients, measure phenotypes of ~6-year-old common-garden plants of 8 taxa to verify heritability of phenotypes, and examine genotypes of 476 wild adults at 9 microsatellite loci to compare the strengths of isolation across taxa, volcanoes, and distance. All 8 taxa retained their diagnostic phenotypes in the common garden. Populations were isolated by taxon to a range of degrees (pairwise FST between taxa: 0.004–0.267), and there was no pattern of isolation by distance or by elevation; however, significant isolation between volcanoes was observed within monotypic species, suggesting limited gene flow between volcanoes. Among the infraspecific taxa of Metrosideros polymorpha, genetic diversity and isolation significantly decreased and increased, respectively, with elevation. Overall, 5 of the 6 most isolated taxa were associated with highest elevations or otherwise extreme environments. These findings suggest a principal role for selection in the origin and maintenance of the exceptional diversity that occurs within continuous Metrosideros stands on Oʻahu.

Invasive and Quarantine Risks of Cacopsylla chinensis (Hemiptera: Psyllidae) in East Asia: Hybridization or Gene Flow Between Differentiated Lineages

2020 ◽  
Vol 113 (6) ◽  
pp. 2890-2899
Author(s):  
Cheng-Lung Tsai ◽  
Hsien-Chung Lee ◽  
Geonho Cho ◽  
Yi-Chang Liao ◽  
Man-Miao Yang ◽  
...  
Keyword(s):  
Gene Flow ◽  
East Asia ◽  
Southern China ◽  
Incomplete Lineage Sorting ◽  
Anthropogenic Activities ◽  
Nuclear Gene ◽  
Population Expansion ◽  
Lineage Sorting ◽  
Recent Population Expansion ◽  
Putative Gene

Abstract Pear psyllids are major pests and the causal agents of pear decline disease in orchards. In the past two decades, their outbreaks have raised issues pertaining to invasions and taxonomic identification of the dimorphic Cacopsylla chinensis (Yang and Li) in East Asia. The present study elucidated, as an aid to quarantine management, the invasive origins, differentiation history, and putative gene flow and hybridization between C. chinensis and its sibling species Cacopsylla jukyungi (Kwon). Analyses revealed that the ancestors of C. jukyungi might have diverged from C. chinensis approximately 3.5 million yr ago (Mya) and that differentiation between C. chinensis lineages I and II probably occurred 1.5 Mya. The known overlapping distribution of C. chinensis and C. jukyungi in northeastern China and the two C. chinensis lineages in the Bohai Rim region and Taiwan could be attributed to recent population expansion after the Last Glacial Maximum and/or anthropogenic activities. Analyses of the nuclear gene demonstrated that frequent gene flow between the two C. chinensis lineages and the paraphyletic relationship between C. chinensis and C. jukyungi might be caused by incomplete lineage sorting or hybridization events. On the basis of the current distribution, it is evident that C. jukyungi is not present in middle-southern China, whereas C. chinensis is not distributed in Japan and Korea. Preventing new invasions of Cacopsylla psyllids among geographic regions through the transportation of pear scions is thus pivotal in East Asia, particularly for the possible genetic exchanges among differentiated lineages after secondary invasion events.

Differentiation and Interrelations of Two Representatives of Laudakia stellio Complex (Reptilia: Agamidae) in Israel

2011 ◽  
Vol 4 (2) ◽  
pp. 102-114 ◽  
Author(s):  
Evgenyi N. Panov ◽  
Larissa Yu. Zykova
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Habitat Preference ◽  
Additional Data ◽  
Near East ◽  
Field Studies ◽  
Subspecies Level ◽  
Limited Gene Flow ◽  
Study Sites ◽  
And Behavior

Field studies were conducted in Central Negev within the breeding range of Laudakia stellio brachydactyla and in NE Israel (Qyriat Shemona) in the range of an unnamed form (tentatively “Near-East Rock Agama”), during March – May 1996. Additional data have been collected in Jerusalem at a distance of ca. 110 km from the first and about 170 km from the second study sites. A total of 63 individuals were caught and examined. The animals were marked and their subsequent movements were followed. Social and signal behavior of both forms were described and compared. Lizards from Negev and Qyriat Shemona differ from each other sharply in external morphology, habitat preference, population structure, and behavior. The differences obviously exceed the subspecies level. At the same time, the lizards from Jerusalem tend to be intermediate morphologically between those from both above-named localities, which permits admitting the existence of a limited gene flow between lizard populations of Negev and northern Israel. The lizards from NE Israel apparently do not belong to the nominate subspecies of L. stellio and should be regarded as one more subspecies within the species.

Population fragmentation causes inadequate gene flow and increases extinction risk

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Gene Flow ◽  
Extinction Risk ◽  
Random Mating ◽  
Large Population ◽  
Isolated Population ◽  
Population Fragmentation ◽  
Single Population ◽  
Total Size ◽  
Limited Gene Flow

Most species now have fragmented distributions, often with adverse genetic consequences. The genetic impacts of population fragmentation depend critically upon gene flow among fragments and their effective sizes. Fragmentation with cessation of gene flow is highly harmful in the long term, leading to greater inbreeding, increased loss of genetic diversity, decreased likelihood of evolutionary adaptation and elevated extinction risk, when compared to a single population of the same total size. The consequences of fragmentation with limited gene flow typically lie between those for a large population with random mating and isolated population fragments with no gene flow.

High gene flow through pollen partially compensates spatial limited gene flow by seeds for a Neotropical tree in forest conservation and restoration areas

2021 ◽  
Author(s):  
Patricia Sanae Sujii ◽  
Evandro Vagner Tambarussi ◽  
Carolina Grando ◽  
Ellida de Aguiar Silvestre ◽  
João Paulo Gomes Viana ◽  
...  
Keyword(s):  
Gene Flow ◽  
Forest Conservation ◽  
Neotropical Tree ◽  
High Gene Flow ◽  
High Gene ◽  
Limited Gene Flow ◽  
Flow Through

scholarly journals Expansion of Genetic Diversity in Randomly Mating Founder Populations of Alternaria brassicicola Infecting Cakile maritima in Australia

2010 ◽  
Vol 76 (6) ◽  
pp. 1946-1954 ◽  
Author(s):  
C. C. Linde ◽  
J. A. Liles ◽  
P. H. Thrall
Keyword(s):  
Genetic Diversity ◽  
Plant Pathogens ◽  
Isolation By Distance ◽  
Population Expansion ◽  
Alternaria Brassicicola ◽  
Evolutionary Potential ◽  
Recent Population Expansion ◽  
Fungal Plant Pathogens ◽  
Cakile Maritima ◽  
Founder Populations

ABSTRACT Founder populations of fungal plant pathogens are expected to have low levels of genetic diversity coupled with further genetic drift due to, e.g., limited host availability, which should result in additional population bottlenecks. This study used microsatellite markers in the interaction between Cakile maritima and the fungal pathogen Alternaria brassicicola to explore genetic expectations associated with such situations. The host, C. maritima, was introduced into Australia approximately 100 years ago, but it is unknown whether the pathogen was already present in Australia, as it has a wide occurrence, or whether it was introduced to Australia on brassicaceous hosts. Eleven A. brassicicola populations were studied, and all showed moderate levels of gene and genotypic diversity. Chi-square tests of the frequencies of mating type alleles, a large number of genotypes, and linkage equilibrium among microsatellite loci all suggest A. brassicicola reproduces sexually. Significant genetic differentiation was found among populations, but there was no evidence for isolation by distance effects. Bayesian analyses identified eight clusters where the inferred clusters did not represent geographical populations but instead consisted of individuals admixed from all populations. Further analysis indicated that fungal populations were more likely to have experienced a recent population expansion than a population bottleneck. It is suggested that A. brassicicola has been introduced into Australia multiple times, potentially increasing the diversity and size of any A. brassicola populations already present there. Combined with its ability to reproduce sexually, such processes appear to have increased the evolutionary potential of the pathogen through recent population expansions.

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