scholarly journals Whole-genome sequencing reveals the extent of heterozygosity in a preferentially self-fertilizing hermaphroditic vertebrate

Genome ◽  
2018 ◽  
Vol 61 (4) ◽  
pp. 241-247 ◽  
Author(s):  
Luana S.F. Lins ◽  
Shawn Trojahn ◽  
Alexandra Sockell ◽  
Muh-Ching Yee ◽  
Andrey Tatarenkov ◽  
...  

The mangrove rivulus, Kryptolebias marmoratus, is one of only two self-fertilizing hermaphroditic fish species and inhabits mangrove forests. While selfing can be advantageous, it reduces heterozygosity and decreases genetic diversity. Studies using microsatellites found that there are variable levels of selfing among populations of K. marmoratus, but overall, there is a low rate of outcrossing and, therefore, low heterozygosity. In this study, we used whole-genome data to assess the levels of heterozygosity in different lineages of the mangrove rivulus and infer the phylogenetic relationships among those lineages. We sequenced whole genomes from 15 lineages that were completely homozygous at microsatellite loci and used single nucleotide polymorphisms (SNPs) to determine heterozygosity levels. More variation was uncovered than in studies using microsatellite data because of the resolution of full genome sequencing data. Moreover, missense polymorphisms were found most often in genes associated with immune function and reproduction. Inferred phylogenetic relationships suggest that lineages largely group by their geographic distribution. The use of whole-genome data provided further insight into genetic diversity in this unique species. Although this study was limited by the number of lineages that were available, these data suggest that there is previously undescribed variation within lineages of K. marmoratus that could have functional consequences and (or) inform us about the limits to selfing (e.g., genetic load, accumulation of deleterious mutations) and selection that might favor the maintenance of heterozygosity. These results highlight the need to sequence additional individuals within and among lineages.

Heredity ◽  
2021 ◽  
Author(s):  
Axel Jensen ◽  
Mette Lillie ◽  
Kristofer Bergström ◽  
Per Larsson ◽  
Jacob Höglund

AbstractThe use of genetic markers in the context of conservation is largely being outcompeted by whole-genome data. Comparative studies between the two are sparse, and the knowledge about potential effects of this methodology shift is limited. Here, we used whole-genome sequencing data to assess the genetic status of peripheral populations of the wels catfish (Silurus glanis), and discuss the results in light of a recent microsatellite study of the same populations. The Swedish populations of the wels catfish have suffered from severe declines during the last centuries and persists in only a few isolated water systems. Fragmented populations generally are at greater risk of extinction, for example due to loss of genetic diversity, and may thus require conservation actions. We sequenced individuals from the three remaining native populations (Båven, Emån, and Möckeln) and one reintroduced population of admixed origin (Helge å), and found that genetic diversity was highest in Emån but low overall, with strong differentiation among the populations. No signature of recent inbreeding was found, but a considerable number of short runs of homozygosity were present in all populations, likely linked to historically small population sizes and bottleneck events. Genetic substructure within any of the native populations was at best weak. Individuals from the admixed population Helge å shared most genetic ancestry with the Båven population (72%). Our results are largely in agreement with the microsatellite study, and stresses the need to protect these isolated populations at the northern edge of the distribution of the species.


2020 ◽  
Vol 47 (12) ◽  
pp. 9995-10003
Author(s):  
Agnieszka Kaczmarczyk-Ziemba

AbstractThe freshwater true bug Aphelocheirus aestivalis (Aphelocheiridae) is widely distributed in Europe but occurs rather locally and often in isolated populations. Moreover, it is threatened with extinction in parts of its range. Unfortunately, little is known about the genetic diversity and population structure due to the lack of molecular tools for this species. Thus, to overcome the limitations, a whole-genome sequencing has been performed to identify polymorphic microsatellite markers for A. aestivalis. The whole-genome sequencing has been performed with the Illumina MiSeq platform. Obtained paired-end reads were processed and overlapped into 2,378,426 sequences, and the subset of 267 sequences containing microsatellite motifs were then used for in silico primer designing. Finally, 56 microsatellite markers were determined and 34 of them were polymorphic. Analyses performed in two samples (collected from Drawa and Gowienica rivers, respectively) showed that the number of alleles per locus ranged from 2 to 21, and the observed and expected heterozygosity varied from 0 to 0.933 and 0.064 to 0.931, respectively. The microsatellite markers developed in the present study provide new suitable tools available for the scientific community to study A. aestivalis population dynamics. The assessment of its genetic diversity and population structure will provide important data, that can be used in population management and conservation efforts, elucidating the broad- and fine-scale population genetic structure of A. aestivalis.


2020 ◽  
Author(s):  
Hengyou Zhang ◽  
He Jiang ◽  
Zhenbin Hu ◽  
Qijian Song ◽  
Yong-qiang Charles An

SummaryWith the advance of next-generation sequencing technologies, over 15 terabytes of raw soybean genome sequencing data were generated and made available in the public. To develop a consolidated, diverse, and user-friendly genomic resource to facilitate post-genomic research, we sequenced 91 highly diverse wild soybean genomes representing the entire US collection of wild soybean accessions to increase the genetic diversity of the sequenced genomes. Having integrated and analyzed the sequencing data with the public data, we identified and annotated 32 million single nucleotide polymorphisms (32mSNPs) with a resolution of 30 SNPs/kb and 12 non-synonymous SNPs/gene in 1,556 accessions (1.5K). Population structure analysis showed that the 1.5K accessions represent the genetic diversity of the 20,087 (20K) soybean accessions in the U.S. collection. Inclusion of wild soybean genomes significantly increased the genetic diversity and shorten linkage disequilibrium distance in the panel of soybean accessions. We identified a collection of paired accessions sharing the highest genomic identity between the 1.5K and 20K accessions as genomically “equivalent” accessions to maximize the use of the genome sequences. We demonstrated that the 32mSNPs in the 1.5K accessions can be effectively used for in-silico genotyping, discovering trait QTL, gene alleles/mutations, identifying germplasms containing beneficial allele and domestication selection of trait alleles. We made the 32mSNPs and 1.5K accessions with detailed annotation available at SoyBase and Ag Data Commons. The dataset could serve as a versatile resource to release the potential of the huge amount of genome sequencing data for a variety of postgenomic research.


2020 ◽  
Vol 66 (1) ◽  
pp. 39-52
Author(s):  
Tomoya Tanjo ◽  
Yosuke Kawai ◽  
Katsushi Tokunaga ◽  
Osamu Ogasawara ◽  
Masao Nagasaki

AbstractStudies in human genetics deal with a plethora of human genome sequencing data that are generated from specimens as well as available on public domains. With the development of various bioinformatics applications, maintaining the productivity of research, managing human genome data, and analyzing downstream data is essential. This review aims to guide struggling researchers to process and analyze these large-scale genomic data to extract relevant information for improved downstream analyses. Here, we discuss worldwide human genome projects that could be integrated into any data for improved analysis. Obtaining human whole-genome sequencing data from both data stores and processes is costly; therefore, we focus on the development of data format and software that manipulate whole-genome sequencing. Once the sequencing is complete and its format and data processing tools are selected, a computational platform is required. For the platform, we describe a multi-cloud strategy that balances between cost, performance, and customizability. A good quality published research relies on data reproducibility to ensure quality results, reusability for applications to other datasets, as well as scalability for the future increase of datasets. To solve these, we describe several key technologies developed in computer science, including workflow engine. We also discuss the ethical guidelines inevitable for human genomic data analysis that differ from model organisms. Finally, the future ideal perspective of data processing and analysis is summarized.


2014 ◽  
Vol 35 (21-22) ◽  
pp. 3102-3110 ◽  
Author(s):  
Anneleen Van Geystelen ◽  
Tom Wenseleers ◽  
Ronny Decorte ◽  
Maarten J. L. Caspers ◽  
Maarten H. D. Larmuseau

mBio ◽  
2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Henju Marjuki ◽  
How-Yi Chang ◽  
Nadav Topaz ◽  
Melissa J. Whaley ◽  
Jeni Vuong ◽  
...  

ABSTRACT Carriage evaluations were conducted during 2015 to 2016 at two U.S. universities in conjunction with the response to disease outbreaks caused by Neisseria meningitidis serogroup B and at a university where outbreak and response activities had not occurred. All eligible students at the two universities received the serogroup B meningococcal factor H binding protein vaccine (MenB-FHbp); 5.2% of students (181/3,509) at one university received MenB-4C. A total of 1,514 meningococcal carriage isolates were obtained from 8,905 oropharyngeal swabs from 7,001 unique participants. Whole-genome sequencing data were analyzed to understand MenB-FHbp’s impact on carriage and antigen genetic diversity and distribution. Of 1,422 isolates from carriers with known vaccination status (726 [51.0%] from MenB-FHbp-vaccinated, 42 [3.0%] from MenB-4C-vaccinated, and 654 [46.0%] from unvaccinated participants), 1,406 (98.9%) had intact fHbp alleles (716 from MenB-FHbp-vaccinated participants). Of 726 isolates from MenB-FHbp-vaccinated participants, 250 (34.4%) harbored FHbp peptides that may be covered by MenB-FHbp. Genogroup B was detected in 122/1,422 (8.6%) and 112/1,422 (7.9%) isolates from MenB-FHbp-vaccinated and unvaccinated participants, respectively. FHbp subfamily and peptide distributions between MenB-FHbp-vaccinated and unvaccinated participants were not statistically different. Eighteen of 161 MenB-FHbp-vaccinated repeat carriers (11.2%) acquired a new strain containing one or more new vaccine antigen peptides during multiple rounds of sample collection, which was not statistically different (P = 0.3176) from the unvaccinated repeat carriers (1/30; 3.3%). Our findings suggest that lack of MenB vaccine impact on carriage was not due to missing the intact fHbp gene; MenB-FHbp did not affect antigen genetic diversity and distribution during the study period. IMPORTANCE The impact of serogroup B meningococcal (MenB) vaccines on carriage is not completely understood. Using whole-genome sequencing data, we assessed the diversity and distribution of MenB vaccine antigens (particularly FHbp) among 1,514 meningococcal carriage isolates recovered from vaccinated and unvaccinated students at three U.S. universities, two of which underwent MenB-FHbp mass vaccination campaigns following meningococcal disease outbreaks. The majority of carriage isolates recovered from participants harbored intact fHbp genes, about half of which were recovered from MenB-FHbp-vaccinated participants. The distribution of vaccine antigen peptides was similar among carriage isolates recovered from vaccinated and unvaccinated participants, and almost all strains recovered from repeat carriers retained the same vaccine antigen profile, suggesting insignificant vaccine selective pressure on the carriage population in these universities.


PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242168
Author(s):  
Julien Paganini ◽  
Peter L. Nagy ◽  
Nicholas Rouse ◽  
Philippe Gouret ◽  
Jacques Chiaroni ◽  
...  

Many questions can be explored thanks to whole-genome data. The aim of this study was to overcome their main limits, software availability and database accuracy, and estimate the feasibility of red blood cell (RBC) antigen typing from whole-genome sequencing (WGS) data. We analyzed whole-genome data from 79 individuals for HLA-DRB1 and 9 RBC antigens. Whole-genome sequencing data was analyzed with software allowing phasing of variable positions to define alleles or haplotypes and validated for HLA typing from next-generation sequencing data. A dedicated database was set up with 1648 variable positions analyzed in KEL (KEL), ACKR1 (FY), SLC14A1 (JK), ACHE (YT), ART4 (DO), AQP1 (CO), CD44 (IN), SLC4A1 (DI) and ICAM4 (LW). Whole-genome sequencing typing was compared to that previously obtained by amplicon-based monoallelic sequencing and by SNaPshot analysis. Whole-genome sequencing data were also explored for other alleles. Our results showed 93% of concordance for blood group polymorphisms and 91% for HLA-DRB1. Incorrect typing and unresolved results confirm that WGS should be considered reliable with read depths strictly above 15x. Our results supported that RBC antigen typing from WGS is feasible but requires improvements in read depth for SNV polymorphisms typing accuracy. We also showed the potential for WGS in screening donors with rare blood antigens, such as weak JK alleles. The development of WGS analysis in immunogenetics laboratories would offer personalized care in the management of RBC disorders.


GigaScience ◽  
2021 ◽  
Vol 10 (11) ◽  
Author(s):  
Milovan Suvakov ◽  
Arijit Panda ◽  
Colin Diesh ◽  
Ian Holmes ◽  
Alexej Abyzov

Abstract Background Detecting copy number variations (CNVs) and copy number alterations (CNAs) based on whole-genome sequencing data is important for personalized genomics and treatment. CNVnator is one of the most popular tools for CNV/CNA discovery and analysis based on read depth. Findings Herein, we present an extension of CNVnator developed in Python—CNVpytor. CNVpytor inherits the reimplemented core engine of its predecessor and extends visualization, modularization, performance, and functionality. Additionally, CNVpytor uses B-allele frequency likelihood information from single-nucleotide polymorphisms and small indels data as additional evidence for CNVs/CNAs and as primary information for copy number–neutral losses of heterozygosity. Conclusions CNVpytor is significantly faster than CNVnator—particularly for parsing alignment files (2–20 times faster)—and has (20–50 times) smaller intermediate files. CNV calls can be filtered using several criteria, annotated, and merged over multiple samples. Modular architecture allows it to be used in shared and cloud environments such as Google Colab and Jupyter notebook. Data can be exported into JBrowse, while a lightweight plugin version of CNVpytor for JBrowse enables nearly instant and GUI-assisted analysis of CNVs by any user. CNVpytor release and the source code are available on GitHub at https://github.com/abyzovlab/CNVpytor under the MIT license.


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