scholarly journals Distribution of genetic diversity reveals colonization patterns and philopatry of the loggerhead sea turtles across geographic scales

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Miguel Baltazar-Soares ◽  
Juliana D. Klein ◽  
Sandra M. Correia ◽  
Thomas Reischig ◽  
Albert Taxonera ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Evolutionary History ◽  
Sea Turtle ◽  
Ocean Basin ◽  
Evolutionary Potential ◽  
Loggerhead Sea Turtles ◽  
Cabo Verde ◽  
Cape Of Good Hope ◽  
Significant Genetic Structure ◽  
The Right

Abstract Understanding the processes that underlie the current distribution of genetic diversity in endangered species is a goal of modern conservation biology. Specifically, the role of colonization and dispersal events throughout a species’ evolutionary history often remains elusive. The loggerhead sea turtle (Caretta caretta) faces multiple conservation challenges due to its migratory nature and philopatric behaviour. Here, using 4207 mtDNA sequences, we analysed the colonisation patterns and distribution of genetic diversity within a major ocean basin (the Atlantic), a regional rookery (Cabo Verde Archipelago) and a local island (Island of Boa Vista, Cabo Verde). Data analysis using hypothesis-driven population genetic models suggests the colonization of the Atlantic has occurred in two distinct waves, each corresponding to a major mtDNA lineage. We propose the oldest lineage entered the basin via the isthmus of Panama and sequentially established aggregations in Brazil, Cabo Verde and in the area of USA and Mexico. The second lineage entered the Atlantic via the Cape of Good Hope, establishing colonies in the Mediterranean Sea, and from then on, re-colonized the already existing rookeries of the Atlantic. At the Cabo Verde level, we reveal an asymmetric gene flow maintaining links across island-specific nesting groups, despite significant genetic structure. This structure stems from female philopatric behaviours, which could further be detected by weak but significant differentiation amongst beaches separated by only a few kilometres on the island of Boa Vista. Exploring biogeographic processes at diverse geographic scales improves our understanding of the complex evolutionary history of highly migratory philopatric species. Unveiling the past facilitates the design of conservation programmes targeting the right management scale to maintain a species’ evolutionary potential.

scholarly journals Distribution of genetic diversity reveals colonization and philopatry of the loggerhead sea turtles across geographic scales

2020 ◽  
Author(s):  
Miguel Baltazar-Soares ◽  
Juliana L. Klein ◽  
Sandra M. Correia ◽  
Thomas Reischig ◽  
Amoros Albert Taxonera ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Sea Turtle ◽  
Ocean Basin ◽  
Adaptive Potential ◽  
Loggerhead Sea Turtles ◽  
Loggerhead Sea Turtle ◽  
Cabo Verde ◽  
Cape Of Good Hope ◽  
Significant Genetic Structure ◽  
The Right

AbstractAimUnderstanding the processes that underlie the distribution of genetic diversity in endangered species is a goal of modern conservation biology. Specifically, how population structure affects genetic diversity and contributes to a species’ adaptive potential remain elusive. The loggerhead sea turtle (Caretta caretta) faces multiple conservation challenges due to its migratory nature and philopatric behaviour.LocationsAtlantic Ocean, Cabo Verde, island of BoavistaMethodsHere, using 4207 mtDNA sequences, we analysed the colonisation patterns and distribution of genetic diversity within a major ocean basin (the Atlantic), a regional rookery (Cabo Verde Archipelago) and a local island (Island of Boavista, Cabo Verde).ResultsHypothesis-driven population genetic models suggest the colonization of the Atlantic has occurred in two distinct waves, each corresponding to major mtDNA lineages. We propose the oldest lineage entered the basin via the isthmus of Panama and sequentially established aggregations in Brazil, Cabo Verde and in the area of USA and Mexico. The second lineage entered the Atlantic via the Cape of Good Hope, establishing colonies in the Mediterranean Sea, and from then on, re-colonized the already existing rookeries of the Atlantic. At the Cabo Verde level, we reveal an asymmetric gene flow maintaining links across nesting groups despite significant genetic structure amongst nesting groups. This structure stems from female philopatric behaviour which could further be detected by weak but significant structure amongst beaches separated by only a few kilometres on the island of Boavista.Main conclusionTo explore demographic processes at diverse geographic scales improves understanding the complex evolutionary history of highly migratory philopatric species. Unveiling the past facilitates the design of conservation programmes targeting the right management scale to maintain a species’ adaptive potential and putative response to human-induced selection.

Genetic rescue by augmenting gene flow

2017 ◽  
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Inbreeding Coefficient ◽  
Outbreeding Depression ◽  
Genetic Rescue ◽  
Evolutionary Potential ◽  
Beneficial Effects ◽  
The Difference ◽  
Inbred Populations ◽  
Harmful Effects

Inbreeding is reduced and genetic diversity enhanced when a small isolated inbred population is crossed to another unrelated population. Crossing can have beneficial or harmful effects on fitness, but beneficial effects predominate, and the risks of harmful ones (outbreeding depression) can be predicted and avoided. For crosses with a low risk of outbreeding depression, there are large and consistent benefits on fitness that persist across generations in outbreeding species. Benefits are greater in species that naturally outbreed than those that inbreed, and increase with the difference in inbreeding coefficient between crossed and inbred populations in mothers and zygotes. However, benefits are similar across invertebrates, vertebrates and plants. There are also important benefits for evolutionary potential of crossing between populations.

scholarly journals Genetic Diversity of Rice stripe necrosis virus and New Insights into Evolution of the Genus Benyvirus

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 737
Author(s):  
Issiaka Bagayoko ◽  
Marcos Giovanni Celli ◽  
Gustavo Romay ◽  
Nils Poulicard ◽  
Agnès Pinel-Galzi ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Sierra Leone ◽  
Evolutionary History ◽  
Molecular Diversity ◽  
Genomic Data ◽  
Gene Recombination ◽  
Necrosis Virus ◽  
History Of ◽  
Complex Evolutionary History

The rice stripe necrosis virus (RSNV) has been reported to infect rice in several countries in Africa and South America, but limited genomic data are currently publicly available. Here, eleven RSNV genomes were entirely sequenced, including the first corpus of RSNV genomes of African isolates. The genetic variability was differently distributed along the two genomic segments. The segment RNA1, within which clusters of polymorphisms were identified, showed a higher nucleotidic variability than did the beet necrotic yellow vein virus (BNYVV) RNA1 segment. The diversity patterns of both viruses were similar in the RNA2 segment, except for an in-frame insertion of 243 nucleotides located in the RSNV tgbp1 gene. Recombination events were detected into RNA1 and RNA2 segments, in particular in the two most divergent RSNV isolates from Colombia and Sierra Leone. In contrast to BNYVV, the RSNV molecular diversity had a geographical structure with two main RSNV lineages distributed in America and in Africa. Our data on the genetic diversity of RSNV revealed unexpected differences with BNYVV suggesting a complex evolutionary history of the genus Benyvirus.

scholarly journals Intelligent Characterization of Lentil Genetic Resources: Evolutionary History, Genetic Diversity of Germplasm, and the Need for Well‐Represented Collections

2021 ◽  
Vol 1 (5) ◽  
Author(s):  
Azalea Guerra‐García ◽  
Tania Gioia ◽  
Eric Wettberg ◽  
Giuseppina Logozzo ◽  
Roberto Papa ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Resources ◽  
Evolutionary History

Microsatellite markers provide evidence for sexual reproduction of Mycosphaerella graminicola in Saskatchewan

Genome ◽  
2004 ◽  
Vol 47 (5) ◽  
pp. 789-794 ◽  
Author(s):  
M Razavi ◽  
G R Hughes
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Sexual Reproduction ◽  
Primary Source ◽  
Mycosphaerella Graminicola ◽  
Septoria Tritici Blotch ◽  
Septoria Tritici ◽  
Allelic Series ◽  
Evolutionary Potential ◽  
Wheat Field

This study examined the genetic structure of a Saskatchewan population of Mycosphaerella graminicola, cause of the foliar disease Septoria tritici blotch of wheat. Such knowledge is valuable for understanding the evolutionary potential of this pathogen and for developing control strategies based on host resistance. Nine pairs of single-locus microsatellite primers were used to analyze the genomic DNA of 90 isolates of M. graminicola that were collected using a hierarchical sampling procedure from different locations, leaves, and lesions within a wheat field near Saskatoon. Allelic series at eight different loci were detected. The number of alleles per locus ranged from one to five with an average of three alleles per locus. Genetic diversity values ranged from 0.04 to 0.67. Partitioning the total genetic variability into within- and among-location components revealed that 88% of the genetic variability occurred within locations, i.e., within areas of 1 m2, but relatively little variability occurred among locations. Low variability among locations and a high degree of variability within locations would result if the primary source of inoculum was airborne ascospores, which would be dispersed uniformly within the field. This finding was confirmed by gametic disequilibrium analysis and suggests that the sexual reproduction of M. graminicola occurs in Saskatchewan.Key words: Mycosphaerella graminicola, SSR markers, sexual reproduction, genetic diversity.

scholarly journals Evolutionary history and genetic connectivity across highly fragmented populations of an endangered daisy

Heredity ◽  
2021 ◽  
Author(s):  
Yael S. Rodger ◽  
Alexandra Pavlova ◽  
Steve Sinclair ◽  
Melinda Pickup ◽  
Paul Sunnucks
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Evolutionary History ◽  
Livestock Grazing ◽  
Genetic Connectivity ◽  
Evolutionary Divergence ◽  
Common Component ◽  
A Genome ◽  
Eastern Australia

AbstractConservation management can be aided by knowledge of genetic diversity and evolutionary history, so that ecological and evolutionary processes can be preserved. The Button Wrinklewort daisy (Rutidosis leptorrhynchoides) was a common component of grassy ecosystems in south-eastern Australia. It is now endangered due to extensive habitat loss and the impacts of livestock grazing, and is currently restricted to a few small populations in two regions >500 km apart, one in Victoria, the other in the Australian Capital Territory and nearby New South Wales (ACT/NSW). Using a genome-wide SNP dataset, we assessed patterns of genetic structure and genetic differentiation of 12 natural diploid populations. We estimated intrapopulation genetic diversity to scope sources for genetic management. Bayesian clustering and principal coordinate analyses showed strong population genetic differentiation between the two regions, and substantial substructure within ACT/NSW. A coalescent tree-building approach implemented in SNAPP indicated evolutionary divergence between the two distant regions. Among the populations screened, the last two known remaining Victorian populations had the highest genetic diversity, despite having among the lowest recent census sizes. A maximum likelihood population tree method implemented in TreeMix suggested little or no recent gene flow except potentially between very close neighbours. Populations that were more genetically distinctive had lower genetic diversity, suggesting that drift in isolation is likely driving population differentiation though loss of diversity, hence re-establishing gene flow among them is desirable. These results provide background knowledge for evidence-based conservation and support genetic rescue within and between regions to elevate genetic diversity and alleviate inbreeding.

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.

scholarly journals SARS-Like Coronaviruses in Horseshoe Bats (Rhinolophus spp.) in Russia, 2020

Viruses ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 113
Author(s):  
Sergey Alkhovsky ◽  
Sergey Lenshin ◽  
Alexey Romashin ◽  
Tatyana Vishnevskaya ◽  
Oleg Vyshemirsky ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Evolutionary History ◽  
Structural Proteins ◽  
Rt Pcr ◽  
Phylogenetic Lineage ◽  
History Of ◽  
Horseshoe Bats ◽  
Regions Of Russia ◽  
Nonstructural Genes

We found and genetically described two novel SARS-like coronaviruses in feces and oral swabs of the greater (R. ferrumequinum) and the lesser (R. hipposideros) horseshoe bats in southern regions of Russia. The viruses, named Khosta-1 and Khosta-2, together with related viruses from Bulgaria and Kenya, form a separate phylogenetic lineage. We found evidence of recombination events in the evolutionary history of Khosta-1, which involved the acquisition of the structural proteins S, E, and M, as well as the nonstructural genes ORF3, ORF6, ORF7a, and ORF7b, from a virus that is related to the Kenyan isolate BtKY72. The examination of bats by RT-PCR revealed that 62.5% of the greater horseshoe bats in one of the caves were positive for Khosta-1 virus, while its overall prevalence was 14%. The prevalence of Khosta-2 was 1.75%. Our results show that SARS-like coronaviruses circulate in horseshoe bats in the region, and we provide new data on their genetic diversity.

scholarly journals The role of environment, local adaptation and past climate fluctuation on the amount and distribution of genetic diversity in the teosinte in Mexico

2019 ◽  
Author(s):  
Jaime Gasca-Pineda ◽  
Yocelyn T. Gutiérrez-Guerrero ◽  
Erika Aguirre-Planter ◽  
Luis E. Eguiarte
Keyword(s):  
Genetic Diversity ◽  
Local Adaptation ◽  
Environmental Conditions ◽  
Wide Distribution ◽  
Wide Range ◽  
Significant Genetic Structure ◽  
Nuclear Microsatellite ◽  
Genetic Clusters ◽  
Assignment Analysis ◽  
Climate Fluctuation

AbstractWild maize, commonly known as teosinte, has a wide distribution in central Mexico and inhabits a wide range of environmental conditions. According to previous studies, the environment is a determinant factor for the amount and distribution of genetic diversity. In this study, we used a set of neutral markers to explore the influence of contemporary factors and historical environmental shifts on genetic diversity, including present and three historical periods. Using a set of 22 nuclear microsatellite loci, we genotyped 527 individuals from 29 localities. We found highly variable levels of genetic diversity (Z. m. parviglumis HE= 0.3646–0.7699; Z. m. mexicana HE= 0.5885–0.7671) and significant genetic structure among localities (average DEST= 0.4332). Also, we recovered significant values of heterozygote deficiency (average FIS= 0.1796) and variable levels of selfing (sg2=0.0–0.3090). The Bayesian assignment analysis yielded four genetic clusters dividing the sample into subspecies, that in turn, were separated into two clusters. Environmental conditions played a strong influence in the distribution of genetic diversity, as demographic analysis and changes in species range revealed by modeling analyses were consistent. We conclude that current genetic diversity in teosinte is the result of a mixture of local adaptation and genetic isolation along with historical environmental fluctuations.

Unusual giant pleural lipomas: imaging features

2021 ◽  
Vol 14 (6) ◽  
pp. e238870
Author(s):  
Dipin Sudhakaran ◽  
Sheragaru Hanumanthappa Chandrashekhara ◽  
Sunil Kumar ◽  
Mohamed Sulaiman
Keyword(s):  
Intercostal Space ◽  
Parietal Pleura ◽  
Imaging Features ◽  
Thoracic Cavity ◽  
Evolutionary Potential ◽  
The Right

Pleural lipomas are rarely encountered in the thoracic cavity. Sometimes, they infiltrate the intercostal space to have a component on either side of the intercostal space forming a hourglass configuration. They are generally solitary, small and asymptomatic. We present the case of a 49-year-old man with two giant pleural lipomas, both originating from the right parietal pleura, and one of which was passing through the intercostal space giving rise to a hourglass-shaped configuration. When they occur, although benign, considering the evolutionary potential, excision is recommended.

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