scholarly journals Local parasite pressures and host genotype may modulate epigenetic diversity in a mixed-mating fish

2019 ◽  
Author(s):  
Waldir M. Berbel-Filho ◽  
Carlos Garcia de Leaniz ◽  
Paloma Morán ◽  
Jo Cable ◽  
Sergio M. Q. Lima ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Dna Methylation ◽  
Genetic Variation ◽  
Natural Populations ◽  
Mixed Mating ◽  
Host Genotype ◽  
Genetic Population ◽  
Low Genetic Diversity ◽  
Population Structuring ◽  
Epigenetic Diversity

AbstractParasite-mediated selection is one of the main drivers of genetic variation in natural populations. The persistence of asexual reproduction and self-fertilization, however, challenges the notion that low genetic variation and inbreeding compromise the host’s ability to respond to pathogens. DNA methylation represents a potential mechanism for generating additional adaptive variation under low genetic diversity. We compared genetic diversity (microsatellites and AFLPs), variation in DNA methylation (MSAFLPs), and parasite loads in three populations of Kryptolebias hermaphroditus, a unique mixed-mating (partially self-fertilising) fish, to analyse the potential adaptive value of DNA methylation in relation to genetic diversity and parasite loads. We found strong genetic population structuring, as well as differences in parasite loads and methylation levels among sampling sites and selfing lineages. Globally, the interaction between parasites and inbreeding with selfing lineages influenced DNA methylation, but parasites seemed more important in determining methylation levels at the local scale.

scholarly journals Genetic and Epigenetic Changes during the Upward Expansion of Deyeuxia angustifolia Kom. in the Alpine Tundra of the Changbai Mountains, China

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 291
Author(s):  
Biao Ni ◽  
Jian You ◽  
Jiangnan Li ◽  
Yingda Du ◽  
Wei Zhao ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Dna Methylation ◽  
Genetic Variation ◽  
Soil Properties ◽  
Changbai Mountains ◽  
Epigenetic Variation ◽  
Geographical Distance ◽  
Mantel Tests ◽  
Epigenetic Diversity ◽  
Different Populations

Ecological adaptation plays an important role in the process of plant expansion, and genetics and epigenetics are important in the process of plant adaptation. In this study, genetic and epigenetic analyses and soil properties were performed on D. angustifolia of 17 populations, which were selected in the tundra zone on the western slope of the Changbai Mountains. Our results showed that the levels of genetic and epigenetic diversity of D. angustifolia were relatively low, and the main variation occurred among different populations (amplified fragment length polymorphism (AFLP): 95%, methylation sensitive amplification polymorphism (MSAP): 87%). In addition, DNA methylation levels varied from 23.36% to 35.70%. Principal component analysis (PCA) results showed that soil properties of different populations were heterogeneous. Correlation analyses showed that soil moisture, pH and total nitrogen were significantly correlated with genetic diversity of D. angustifolia, and soil temperature and pH were closely related to epigenetic diversity. Simple Mantel tests and partial Mantel tests showed that genetic variation significantly correlated with habitat or geographical distance. However, the correlation between epigenetic variation and habitat or geographical distance was not significant. Our results showed that, in the case of low genetic variation and genetic diversity, epigenetic variation and DNA methylation may provide a basis for the adaptation of D. angustifolia.

scholarly journals Inheritance of DNA methylation differences in the mangrove Rhizophora mangle

2020 ◽  
Author(s):  
Jeannie Mounger ◽  
M. Teresa Boquete ◽  
Marc W. Schmid ◽  
Renan Granado ◽  
Marta H. Robertson ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Genetic Variation ◽  
Gulf Coast ◽  
Natural Populations ◽  
Rhizophora Mangle ◽  
Genotyping By Sequencing ◽  
Foundation Species ◽  
Ecosystem Functions ◽  
Epigenetic Variation ◽  
Epigenetic Diversity

AbstractThe capacity to respond to environmental challenges ultimately relies on phenotypic variation which manifests from complex interactions of genetic and non-genetic mechanisms through development. While we know something about genetic variation and structure of many species of conservation importance, we know very little about the non-genetic contributions to variation. Rhizophora mangle is a foundation species that occurs in coastal estuarine habitats throughout the neotropics where it provides critical ecosystem functions, and is potentially threatened by climate change. Several studies have documented landscape level patterns of genetic variation in this species, but we know virtually nothing about the inheritance of non-genetic variation. To assess one type of non-genetic variation, we examined the patterns of DNA sequence and DNA methylation in maternal plants and offspring from natural populations of R. mangle from the Gulf Coast of Florida. We used a reduced representation bisulfite sequencing approach (epi-genotyping by sequencing or epiGBS) to address the following questions: a) What are the levels of genetic and epigenetic diversity in natural populations of R. mangle? b) How are genetic and epigenetic variation structured within and among populations? c) How faithfully is epigenetic variation inherited? We found low genetic diversity but high epigenetic diversity from natural populations of maternal plants in the field and that a large portion (up to ~25%) of epigenetic differences among offspring grown in common garden was explained by maternal family. Therefore, epigenetic variation could be an important source of response to challenging environments in the genetically depauperate populations of this foundation species.

scholarly journals Moderate Genetic Diversity and Demographic Reduction in the Threatened Giant Anteater, Myrmecophaga tridactyla

2021 ◽  
Vol 12 ◽  
Author(s):  
Carmen Elena Barragán-Ruiz ◽  
Rosane Silva-Santos ◽  
Bruno H. Saranholi ◽  
Arnaud L. J. Desbiez ◽  
Pedro Manoel Galetti
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Western Region ◽  
Mammal Species ◽  
Genetic Population ◽  
Entire Area ◽  
Flow Restriction ◽  
Population Structuring ◽  
Recent Bottleneck

In general, large mammal species with highly specialized feeding behavior and solitary habits are expected to suffer genetic consequences from habitat loss and fragmentation. To test this hypothesis, we analyzed the genetic diversity distribution of the threatened giant anteater inhabiting a human-modified landscape. We used 10 microsatellite loci to assess the genetic diversity and population structure of 107 giant anteaters sampled in the Brazilian Central-Western region. No genetic population structuring was observed in this region suggesting no gene flow restriction within the studied area. On the other hand, the moderate level of genetic diversity (Ho = 0.54), recent bottleneck detected and inbreeding (Fis, 0.13; p ≤ 0.001) signatures suggest potential impacts on the genetic variation of this Xenarthra. Additionally, a previous demographic reduction was suggested. Thus, considering the increased human-promoted impacts across the entire area of distribution of the giant anteater, our results can illustrate the potential effects of these disturbances on the genetic variation, allowing us to request the long-term conservation of this emblematic species.

scholarly journals Parasite variation and the evolution of virulence in a Daphnia-microparasite system

Parasitology ◽  
2007 ◽  
Vol 135 (3) ◽  
pp. 303-308 ◽  
Author(s):  
T. J. LITTLE ◽  
W. CHADWICK ◽  
K. WATT
Keyword(s):  
Genetic Variation ◽  
Rank Order ◽  
Genetic Relationships ◽  
Natural Populations ◽  
Host Genotype ◽  
Relative Growth ◽  
Trade Off ◽  
Relative Growth Rates ◽  
Pasteuria Ramosa ◽  
Evolution Of Virulence

SUMMARYUnderstanding genetic relationships amongst the life-history traits of parasites is crucial for testing hypotheses on the evolution of virulence. This study therefore examined variation between parasite isolates (the bacterium Pasteuria ramosa) from the crustacean Daphnia magna. From a single wild-caught infected host we obtained 2 P. ramosa isolates that differed substantially in the mortality they caused. Surprisingly, the isolate causing higher early mortality was, on average, less successful at establishing infections and had a slower growth rate within hosts. The observation that within-host replication rate was negatively correlated with mortality could violate a central assumption of the trade-off hypothesis for the evolution of virulence, but we discuss a number of caveats which caution against premature rejection of the trade-off hypothesis. We sought to test if the characteristics of these parasite isolates were constant across host genotypes in a second experiment that included 2 Daphnia host clones. The relative growth rates of the two parasite isolates did indeed depend on the host genotype (although the rank order did not change). We suggest that testing evolutionary hypotheses for virulence may require substantial sampling of both host and parasite genetic variation, and discuss how selection for virulence may change with the epidemiological state of natural populations and how this can promote genetic variation for virulence.

scholarly journals Determining Whether Geographic Origin and Potato Genotypes Shape the Population Structure of Phytophthora infestans in the Central Region of Colombia

2019 ◽  
Vol 109 (1) ◽  
pp. 145-154
Author(s):  
Sandra Catalina Chaves ◽  
María Camila Rodríguez ◽  
María Fernanda Mideros ◽  
Florencia Lucca ◽  
Carlos E. Ñústez ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Phytophthora Infestans ◽  
Central Region ◽  
Geographic Origin ◽  
Geographic Area ◽  
Potato Cultivars ◽  
Clonal Lineage ◽  
Host Genotype ◽  
Genetic Population

Pathogen variation plays an important role in the dynamics of infectious diseases. In this study, the genetic variation of 279 Phytophthora infestans isolates was assessed using a combination of 12 microsatellite simple-sequence repeat markers. Isolates were collected from 11 different potato cultivars in 11 different geographic localities of the central region of Colombia. The objective of this study was to determine whether populations were differentiated by host genotype or geographic origin. Within a single clonal lineage, EC-1, 76 genotypes were detected. An analysis of molecular variance attributed most of the variation to differences within host genotypes rather than among the host genotypes, suggesting that host cultivars do not structure the populations of the pathogen. Furthermore, the lack of a genetic population structure according to the host cultivar was confirmed by all of the analyses, including the Bayesian clustering analysis and the minimum spanning network that used the Bruvo genetic distance, which suggested that there are no significant barriers to gene flow for P. infestans among potato cultivars. According to the geographic origin, the populations of P. infestans were also not structured, and most of the variation among the isolates was attributed to differences within localities. Only some but not all localities in the north and west of the central region of Colombia showed some genetic differentiation from the other regions. The absence of sexual reproduction of this pathogen in Colombia was also demonstrated. Important insights are discussed regarding the genetic population dynamics of the P. infestans populations of the central region of Colombia that were provided by the results. In Colombia, there is a high genetic variation within the EC-1 clonal lineage with closely related genotypes, none dominant, that coexist in a wide geographic area and on several potato cultivars.

scholarly journals Coalescent Theory of Migration Network Motifs

2019 ◽  
Vol 36 (10) ◽  
pp. 2358-2374
Author(s):  
Nicolas Alcala ◽  
Amy Goldberg ◽  
Uma Ramakrishnan ◽  
Noah A Rosenberg
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Nucleotide Diversity ◽  
Natural Populations ◽  
Node Degree ◽  
Small Subset ◽  
Network Motifs ◽  
Coalescent Theory ◽  
Migration Networks ◽  
The Impact

Abstract Natural populations display a variety of spatial arrangements, each potentially with a distinctive impact on genetic diversity and genetic differentiation among subpopulations. Although the spatial arrangement of populations can lead to intricate migration networks, theoretical developments have focused mainly on a small subset of such networks, emphasizing the island-migration and stepping-stone models. In this study, we investigate all small network motifs: the set of all possible migration networks among populations subdivided into at most four subpopulations. For each motif, we use coalescent theory to derive expectations for three quantities that describe genetic variation: nucleotide diversity, FST, and half-time to equilibrium diversity. We describe the impact of network properties on these quantities, finding that motifs with a high mean node degree have the largest nucleotide diversity and the longest time to equilibrium, whereas motifs with low density have the largest FST. In addition, we show that the motifs whose pattern of variation is most strongly influenced by loss of a connection or a subpopulation are those that can be split easily into disconnected components. We illustrate our results using two example data sets—sky island birds of genus Sholicola and Indian tigers—identifying disturbance scenarios that produce the greatest reduction in genetic diversity; for tigers, we also compare the benefits of two assisted gene flow scenarios. Our results have consequences for understanding the effect of geography on genetic diversity, and they can assist in designing strategies to alter population migration networks toward maximizing genetic variation in the context of conservation of endangered species.

scholarly journals Extending the Genotype in Brachypodium by Including DNA Methylation Reveals a Joint Contribution with Genetics on Adaptive Traits

2020 ◽  
Vol 10 (5) ◽  
pp. 1629-1637 ◽  
Author(s):  
Steven R. Eichten ◽  
Akanksha Srivastava ◽  
Adam J. Reddiex ◽  
Diep R. Ganguly ◽  
Alison Heussler ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Dna Methylation ◽  
Phenotypic Variation ◽  
Genetic Relationships ◽  
Natural Populations ◽  
Epigenetic Inheritance ◽  
Genetic Differences ◽  
Linear Modeling ◽  
Climate Conditions ◽  
Joint Contribution

Epigenomic changes have been considered a potential missing link underlying phenotypic variation in quantitative traits but is potentially confounded with the underlying DNA sequence variation. Although the concept of epigenetic inheritance has been discussed in depth, there have been few studies attempting to directly dissect the amount of epigenomic variation within inbred natural populations while also accounting for genetic diversity. By using known genetic relationships between Brachypodium lines, multiple sets of nearly identical accession families were selected for phenotypic studies and DNA methylome profiling to investigate the dual role of (epi)genetics under simulated natural seasonal climate conditions. Despite reduced genetic diversity, appreciable phenotypic variation was still observable in the measured traits (height, leaf width and length, tiller count, flowering time, ear count) between as well as within the inbred accessions. However, with reduced genetic diversity there was diminished variation in DNA methylation within families. Mixed-effects linear modeling revealed large genetic differences between families and a minor contribution of DNA methylation variation on phenotypic variation in select traits. Taken together, this analysis suggests a limited but significant contribution of DNA methylation toward heritable phenotypic variation relative to genetic differences.

scholarly journals Keragaman Genetik Kukang Jawa (Nycticebus javanicus) Menggunakan Control Region (D-loop) DNA Mitokondria (mtDNA) (GENETIC DIVERSITY ON JAVAN SLOW LORIS (NYCTICEBUS JAVANICUS) USING OF CONTROL REGION (D-LOOP) mtDNA)

2019 ◽  
Vol 20 (3) ◽  
pp. 360
Author(s):  
Wirdateti Wirdateti ◽  
Hayati Aziza ◽  
Handayani Handayani
Keyword(s):  
Genetic Diversity ◽  
Genetic Distance ◽  
Control Region ◽  
West Java ◽  
Slow Loris ◽  
Genetic Population ◽  
Central Java ◽  
Low Genetic Diversity ◽  
The Status ◽  
D Loop

Javan slow loris (Nycticebus javanicus)  one of the species of the genus Nycticebus is endemic in Java.  Their distribution region  is in West Java and Banten, and also reported to be found in Central Java and East Java, although very rarely.  Status of the species is Critically Endangered due to high levels of poaching, habitat loss and habitat fragmentation, so that the necessary conservation in order to increase the population. For conservation management it is necessary to know the status of genetic resources that play of  role in breeding, then this research is to explore the genetic population of the Javan slow loris  from some locations in West Java. The research objective was to assess the diversity of their current population of Java loris through the control region (D-loop) of mitochondrial DNA (mtDNA). A total of 23 individuals samples from Gunung Halimun Park, Tasikmalaya, Garut, Ciamis, Jember and confiscated at the Rehabilitation Center IAR Bogor were used in this stydy. Specific primers of D-loop are used for loris with a length of 296 bp sequence. The result showed there are only five different sites and formed six haplotypes, each haplotypes only 1-3 nucleotides different. Low genetic diversity is shown as much as 42.96% of individuals show the same sequence or genetic distance (d) = 0 that indicate was monomorf population from different population. The genetic distance of the entire population was 0.003 ± 0:01 (0.3%).

Schistosome genetic diversity: the implications of population structure as detected with microsatellite markers

Parasitology ◽  
2002 ◽  
Vol 125 (7) ◽  
pp. S51-S59 ◽  
Author(s):  
J. CURTIS ◽  
R. E. SORENSEN ◽  
D. J. MINCHELLA
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
Molecular Markers ◽  
Microsatellite Markers ◽  
Natural Populations ◽  
Mitochondrial Marker ◽  
Tropical Regions ◽  
Blood Flukes

Blood flukes in the genus Schistosoma are important human parasites in tropical regions. A substantial amount of genetic diversity has been described in populations of these parasites using molecular markers. We first consider the extent of genetic variation found in Schistosoma mansoni and some factors that may be contributing to this variation. Recently, though, attempts have been made to analyze not only the genetic diversity but how that diversity is partitioned within natural populations of schistosomes. Studies with non-allelic molecular markers (e.g. RAPDs and mtVNTRs) have indicated that schistosome populations exhibit varying levels of gene flow among component subpopulations. The recent characterization of microsatellite markers for S. mansoni provided an opportunity to study schistosome population structure within a population of schistosomes from a single Brazilian village using allelic markers. Whereas the detection of population structure depends strongly on the type of analysis with a mitochondrial marker, analyses with a set of seven microsatellite loci consistently revealed moderate genetic differentiation when village boroughs were used to define parasite subpopulations and greater subdivision when human hosts defined subpopulations. Finally, we discuss the implications that such strong population structure might have on schistosome epidemiology.

scholarly journals Unusually Low Levels of Genetic Variation among Giardia lamblia Isolates

2007 ◽  
Vol 6 (8) ◽  
pp. 1421-1430 ◽  
Author(s):  
Smilja Teodorovic ◽  
John M. Braverman ◽  
Heidi G. Elmendorf
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Giardia Lamblia ◽  
Diarrheal Disease ◽  
Regulation Of Gene Expression ◽  
Genetic Exchange ◽  
Disease Etiology ◽  
Noncoding Regions ◽  
Low Genetic Diversity ◽  
Low Levels

ABSTRACT Giardia lamblia, an intestinal pathogen of mammals, including humans, is a significant cause of diarrheal disease around the world. Additionally, the parasite is found on a lineage which separated early from the main branch in eukaryotic evolution. The extent of genetic diversity among G. lamblia isolates is insufficiently understood, but this knowledge is a prerequisite to better understand the role of parasite variation in disease etiology and to examine the evolution of mechanisms of genetic exchange among eukaryotes. Intraisolate genetic variation in G. lamblia has never been estimated, and previous studies on interisolate genetic variation have included a limited sample of loci. Here we report a population genetics study of intra- and interisolate genetic diversity based on six coding and four noncoding regions from nine G. lamblia isolates. Our results indicate exceedingly low levels of genetic variation in two out of three G. lamblia groups that infect humans; this variation is sufficient to allow identification of isolate-specific markers. Low genetic diversity at both coding and noncoding regions, with an overall bias towards synonymous substitutions, was discovered. Surprisingly, we found a dichotomous haplotype structure in the third, more variable G. lamblia group, represented by a haplotype shared with one of the homogenous groups and an additional group-specific haplotype. We propose that the distinct patterns of genetic-variation distribution among lineages are a consequence of the presence of genetic exchange. More broadly, our findings have implications for the regulation of gene expression, as well as the mode of reproduction in the parasite.

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