Genetic diversity inCrambe maritimaalong the English Channel: the role of ocean currents in determining population structure

AbstractMosaic aneuploidy prevalent in organisms such as Leishmania and Fungi and in genomes of some neurological disorders and cancers manifest as non-integer haplotypes due to heterogeneity in somy across a population of cells. Thus, the tools designed for strictly haploid or diploid genomes are insufficient to study them. We addressed this issue by upgrading our population genetics tool POPSICLE for aneuploid genomes and studied the population structure of 50 strains of Leishmania to understand genetic diversity and the sexual strategies that predispose to that diversity. Leishmania showed enormous diversity but a dichotomic nature of extreme zygosities. To understand this dichotomy, we specifically studied two species, L. tropica that contained strains with both hetero and homozygosities and L. major that were mainly homozygous. The homozygosity in L. tropica was a consequence of extreme inbreeding while heterozygosity was due to recent hybridizations involving two different genotypes. In contrast, L. major also contained two different genotypes and products of extreme inbreeding but no recent hybridizations. The heterozygous strains of L. tropica that were geographically isolated from the homozygous strains were F1 hybrids that appeared sterile to each other while those in proximity to the homozygous strains were outcrosses involving multiple cycles of hybridization indicating their mating preference with homozygous strains. Development of POPSICLE for aneuploid genomes offers a unique tool for determining the shared ancestries and in reinforcing sex as one of the driving mechanisms for speciation as demonstrated for Leishmania. POPSICLE is a Java based utility available for free download at https://popsicle-admixture.sourceforge.io/

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Population Structure of Dipodomys ingens (Heteromyidae): The Role of Spatial Heterogeneity in Maintaining Genetic Diversity

Evolution ◽

10.2307/2411058 ◽

1997 ◽

Vol 51 (4) ◽

pp. 1296 ◽

Cited By ~ 7

Author(s):

Sara V. Good ◽

Daniel F. Williams ◽

Katherine Ralls ◽

Robert C. Fleischer

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Spatial Heterogeneity ◽

Dipodomys Ingens

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Quantification of Outcrossing Events in Haploid Fungi Using Microsatellite Markers

Journal of Fungi ◽

10.3390/jof6020048 ◽

2020 ◽

Vol 6 (2) ◽

pp. 48

Author(s):

Dong-Hyeon Lee ◽

Brenda D. Wingfield ◽

Jolanda Roux ◽

Michael J. Wingfield

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

High Frequency ◽

Reproductive Strategies ◽

Mating Strategies ◽

Mating Types ◽

Ceratocystis Fimbriata ◽

Mating Type Switching ◽

High Level

Species in genera of the fungal family Ceratocystidaceae are known to have different mating strategies, including heterothallism and homothallism. Of these, species of Ceratocystis, typified by the pathogen Ceratocystis fimbriata all undergo unidirectional mating-type switching. This implies that the pathogens possess the ability to self, but also to undergo sexual outcrossing between isolates of different mating types. In this study, we extended the recently developed microsatellite-based technique to determine the extent to which outcrossing occurs in ascospore masses of haploid fungi to two field collections of Ceratocystis albifundus. In this way, the role of reproductive strategies in shaping population structure and diversity could be better understood. Results showed that a high frequency of outcrossing occurs in isolates of the pathogen from both non-native and native areas. This explains the high level of genetic diversity previously observed in this population despite the fact that this pathogen has the ability to self.

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Genetic diversity and relatedness in aquaculture and marina populations of the invasive tunicate Didemnum vexillum in the British Isles

Biological Invasions ◽

10.1007/s10530-021-02615-3 ◽

2021 ◽

Author(s):

M. B. Prentice ◽

S. R. Vye ◽

S. R. Jenkins ◽

P. W. Shaw ◽

J. E. Ironside

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Native Species ◽

Didemnum Vexillum ◽

Global Spread ◽

History Of ◽

Complex Life History ◽

Source Populations ◽

Successful Invader

AbstractIntroductions of invasive, non-native species in the marine environment are increasing as human activity within coastal areas rises. Genetic datasets are useful tools to identify source populations, track routes of invasions, and illuminate the role of genetic variation in the establishment and subsequent spread of novel introductions. Here, a microsatellite dataset is used to estimate the genetic diversity and population structure of 7 introduced Didemnum vexillum populations in Britain and Ireland, 4 of which are associated with aquaculture and 3 with marinas. Genetic differentiation observed between these populations indicates human-mediated transport as the main mechanism underlying the population structure of D. vexillum in Britain and Ireland. In addition to elucidating patterns of population structure we found that aquaculture sites showed significantly higher genetic diversity (measured as allelic richness) in comparison to the marina sites. We discuss these findings in relation to the history of each invasion, the complex life history of D. vexillum, and available evidence of the relative invasiveness of these populations. Our results show numerous interesting patterns which highlight further research avenues to elucidate the complex factors underlying the global spread of this successful invader.

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