Genetic and Morphological Variation of the Forkbeard, Phycis phycis (Pisces, Phycidae): Evidence of Panmixia and Recent Population Expansion along Its Distribution Area

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.

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

Applied and Environmental Microbiology ◽

10.1128/aem.01594-09 ◽

2010 ◽

Vol 76 (6) ◽

pp. 1946-1954 ◽

Cited By ~ 27

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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Genetic Diversity in the mtDNA control region and population structure of Chrysichthys nigrodigitatus from selected Nigerian rivers: Implications for conservation and aquaculture

Archives of Polish Fisheries ◽

10.1515/aopf-2016-0010 ◽

2016 ◽

Vol 24 (2) ◽

pp. 85-97 ◽

Cited By ~ 2

Author(s):

Sylvanus A. Nwafili ◽

Tian-Xiang Gao

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Control Region ◽

Haplotype Diversity ◽

Population Expansion ◽

Mitochondrial Control Region ◽

Recent Population Expansion ◽

Base Pair Fragment ◽

Population Structures ◽

High Level

Abstract The genetic diversity and population structure of Chrysichthys nigrodigitatus were evaluated using a 443 base pair fragment of the mitochondrial control region. Among the eight populations collected comprising 129 individuals, a total of 89 polymorphic sites defined 57 distinct haplotypes. The mean haplotype diversity and nucleotide diversity of the eight populations were 0.966±0.006 and 0.0359±0.004, respectively. Analysis of molecular variance showed significant genetic differentiation among the eight populations (FST =0.34; P < 0.01). The present results revealed that C. nigrodigitatus populations had a high level of genetic diversity and distinct population structures. We report the existence of two monophyletic matrilineal lineages with mean genetic distance of 10.5% between them. Non-significant negative Tajima’s D and Fu’s Fs for more than half the populations suggests that the wild populations of C. nigrodigitatus underwent a recent population expansion, although a weak one since the late Pleistocene.

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Three phylogenetic groups have driven the recent population expansion of Cryptococcus neoformans

Nature Communications ◽

10.1038/s41467-019-10092-5 ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 13

Author(s):

P. M. Ashton ◽

L. T. Thanh ◽

P. H. Trieu ◽

D. Van Anh ◽

N. M. Trinh ◽

...

Keyword(s):

Cryptococcus Neoformans ◽

Population Expansion ◽

Phylogenetic Groups ◽

Recent Population Expansion

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High levels of genetic diversity inNosema ceranaewithinApis melliferacolonies

Parasitology ◽

10.1017/s0031182013001790 ◽

2013 ◽

Vol 141 (4) ◽

pp. 475-481 ◽

Cited By ~ 17

Author(s):

TAMARA GÓMEZ-MORACHO ◽

XULIO MASIDE ◽

RAQUEL MARTÍN-HERNÁNDEZ ◽

MARIANO HIGES ◽

CAROLINA BARTOLOMÉ

Keyword(s):

Genetic Recombination ◽

Population Expansion ◽

Single Copy ◽

Recent Population Expansion ◽

Colony Losses ◽

Bee Colony ◽

Host Parasite Interactions ◽

Recent Origin ◽

Different Strains ◽

Host Parasite

SUMMARYNosema ceranaeis a widespread honeybee parasite, considered to be one of the pathogens involved in the colony losses phenomenon. To date, little is known about its intraspecific genetic variability. The few studies onN. ceranaevariation have focused on the subunits of ribosomal DNA, which are not ideal for this purpose and have limited resolution. Here we characterized three single copy loci (Actin, Hsp70andRPB1) in threeN. ceranaeisolates from Hungary and Hawaii. Our results provide evidence of unexpectedly high levels of intraspecific polymorphism, the coexistence of a wide variety of haplotypes within each bee colony, and the occurrence of genetic recombination inRPB1. Most haplotypes are not shared across isolates and derive from a few frequent haplotypes by a reduced number of singletons (mutations that appear usually just once in the sample), which suggest that they have a fairly recent origin. Overall, our data indicate that this pathogen has experienced a recent population expansion. The presence of multiple haplotypes within individual isolates could be explained by the existence of different strains ofN. ceranaeinfecting honeybee colonies in the field which complicates, and must not be overlooked, further analysis of host–parasite interactions.

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Signatures of mito-nuclear discordance in Schistosoma turkestanicum indicate a complex evolutionary history of emergence in Europe

Parasitology ◽

10.1017/s0031182017000920 ◽

2017 ◽

Vol 144 (13) ◽

pp. 1752-1762 ◽

Cited By ~ 6

Author(s):

SCOTT P. LAWTON ◽

LAUREN I. BOWEN ◽

AIDAN M. EMERY ◽

GÁBOR MAJOROS

Keyword(s):

Evolutionary History ◽

Molecular Diversity ◽

Population Expansion ◽

Its Sequences ◽

Cox1 Gene ◽

Internal Transcribed Spacer Region ◽

Recent Population Expansion ◽

Haplotype Frequencies ◽

History Of ◽

Low Levels

SUMMARYHigh levels of molecular diversity were identified in mitochondrial cytochrome c oxidase (cox1) gene sequences of Schistosoma turkestanicum from Hungary. These cox1 sequences were all specific to Hungary which contrasted with the low levels of diversity seen in the nuclear internal transcribed spacer region (ITS) sequences, the majority of which were shared between China and Iran isolates. Measures of within and between host molecular variation within S. turkestanicum showed there to be substantial differences in molecular diversity, with cox1 being significantly more diverse than the ITS. Measures of haplotype frequencies revealed that each host contained its own subpopulation of genetically unique parasites with significant levels of differentiation. Pairwise mismatch analysis of cox1 sequences indicated S. turkestanicum populations to have a bimodal pairwise difference distribution and to be stable unlike the ITS sequences, which appeared to have undergone a recent population expansion event. Positive selection was also detected in the cox1 sequences, and biochemical modelling of the resulting protein illustrated significant mutational events causing an alteration to the isoelectric point of the cox1 protein, potentially altering metabolism. The evolutionary signature from the cox1 indicates local adaptation and long establishment of S. turkestanicum in Hungary with continual introgression of nuclear genes from Asian isolates. These processes have led to the occurrence of mito-nuclear discordance in a schistosome population

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Comparative genetic diversity of Cryptosporidium species causing human infections

Parasitology ◽

10.1017/s0031182020001493 ◽

2020 ◽

Vol 147 (13) ◽

pp. 1532-1537 ◽

Cited By ~ 1

Author(s):

Juan C. Garcia-R ◽

Murray P. Cox ◽

David T. S. Hayman

Keyword(s):

Genetic Diversity ◽

Population Expansion ◽

Recent Population Expansion ◽

Cryptosporidium Hominis ◽

High Genetic Diversity ◽

Genetic Changes ◽

Low Genetic Diversity ◽

Human Infections ◽

Host Parasite ◽

Founder Events

AbstractParasites sometimes expand their host range and cause new disease aetiologies. Genetic changes can then occur due to host-specific adaptive alterations, particularly when parasites cross between evolutionarily distant hosts. Characterizing genetic variation in Cryptosporidium from humans and other animals may have important implications for understanding disease dynamics and transmission. We analyse sequences from four loci (gp60, HSP-70, COWP and actin) representing multiple Cryptosporidium species reported in humans. We predicted low genetic diversity in species that present unusual human infections due to founder events and bottlenecks. High genetic diversity was observed in isolates from humans of Cryptosporidium meleagridis, Cryptosporidium cuniculus, Cryptosporidium hominis and Cryptosporidium parvum. A deviation of expected values of neutrality using Tajima's D was observed in C. cuniculus and C. meleagridis. The high genetic diversity in C. meleagridis and C. cuniculus did not match our expectations but deviations from neutrality indicate a recent decrease in genetic variability through a population bottleneck after an expansion event. Cryptosporidium hominis was also found with a significant Tajima's D positive value likely caused by recent population expansion of unusual genotypes in humans. These insights indicate that changes in genetic diversity can help us to understand host-parasite adaptation and evolution.

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Trapped by climate: interglacial refuge and recent population expansion in the endemic Iberian adderVipera seoanei

Diversity and Distributions ◽

10.1111/ddi.12265 ◽

2014 ◽

Vol 21 (3) ◽

pp. 331-344 ◽

Cited By ~ 25

Author(s):

Fernando Martínez-Freiría ◽

Guillermo Velo-Antón ◽

José C. Brito

Keyword(s):

Population Expansion ◽

Recent Population Expansion

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Diploid and tetraploid cytotypes and subspecies of Odontarrhena tortuosa (Brassicaceae) in Pannonia: differences in morphology, ecology and genome size

Phytotaxa ◽

10.11646/phytotaxa.358.2.4 ◽

2018 ◽

Vol 358 (2) ◽

pp. 162

Author(s):

STANISLAV ŠPANIEL ◽

LÝDIA HABURAJOVÁ ◽

VERONIKA CETLOVÁ

Keyword(s):

Genome Size ◽

Central Europe ◽

Morphological Variation ◽

Pannonian Basin ◽

Sand Dunes ◽

Distribution Area ◽

Flow Cytometric Data ◽

Flow Cytometric ◽

Morphological Differences ◽

Rocky Habitats

Odontarrhena tortuosa is a herbaceous species occurring in steppe and rocky habitats of Eurasia. The present study is focused on the cytogeography and morphological variation of the species’ populations growing in the Pannonian basin (Central Europe), which represents the westernmost part of its distribution area. Flow cytometric analyses have revealed the existence of tetraploid populations, which are reported here for the first time for Central Europe. We analysed the morphological variation of 329 individuals from Slovakia, Hungary and Serbia by multivariate morphometric methods to evaluate morphological differences between two cytotypes (diploids and tetraploids), between the subspecies (O. tortuosa subsp. tortuosa and O. tortuosa subsp. heterophylla) and between populations growing in three regions differing in the type of substrate (rocks, sand dunes and sandy and rocky screes). Although we have not found any clear morphological differences between the cytotypes, we have confirmed several previously reported morphological differences between the two subspecies, which occur in regions differing in the type of substrate. Flow cytometric data also indicate certain differences in monoploid genome size between all groups of populations under comparison. Populations from Serbia differ from other populations of O. tortuosa subsp. tortuosa in morphology and genome size, but due to a lack of data on the genetic variation of the species we suggest no change in taxonomy. For the identification of the two subspecies, we present an updated determination key.

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