scholarly journals Geographic cline analysis as a tool for studying genome-wide variation: a case study of pollinator-mediated divergence in a monkeyflower

2016 ◽  
Author(s):  
Sean Stankowski ◽  
James M. Sobel ◽  
Matthew A. Streisfeld

A major goal of speciation research is to reveal the genomic signatures that accompany the speciation process. Genome scans are routinely used to explore genome-wide variation and identify highly differentiated loci that may contribute to ecological divergence, but they do not incorporate spatial, phenotypic, or environmental data that might enhance outlier detection. Geographic cline analysis provides a potential framework for integrating diverse forms of data in a spatially-explicit framework, but it has not been used to study genome-wide patterns of divergence. Aided by a first-draft genome assembly, we combine an FCT scan and geographic cline analysis to characterize patterns of genome-wide divergence between divergent pollination ecotypes of Mimulus aurantiacus. FCT analysis of 58,872 SNPs generated via RADseq revealed little ecotypic differentiation (mean FCT = 0.041), though a small number of loci were moderately to highly diverged. Consistent with our previous results from the gene MaMyb2, which contributes to differences in flower color, 130 loci have cline shapes that recapitulate the spatial pattern of trait divergence, suggesting that they reside in or near the genomic regions that contribute to pollinator isolation. In the narrow hybrid zone between the ecotypes, extensive admixture among individuals and low linkage disequlibrium between markers indicate that outlier loci are scattered throughout the genome, rather than being restricted to one or a few regions. In addition to revealing the genomic consequences of ecological divergence in this system, we discuss how geographic cline analysis is a powerful but under-utilized framework for studying genome-wide patterns of divergence.


2019 ◽  
Vol 110 (4) ◽  
pp. 494-513 ◽  
Author(s):  
Adam G Jones ◽  
Stevan J Arnold ◽  
Reinhard Bürger

Abstract With the advent of next-generation sequencing approaches, the search for individual loci underlying local adaptation has become a major enterprise in evolutionary biology. One promising method to identify such loci is to examine genome-wide patterns of differentiation, using an FST-outlier approach. The effects of pleiotropy and epistasis on this approach are not yet known. Here, we model 2 populations of a sexually reproducing, diploid organism with 2 quantitative traits, one of which is involved in local adaptation. We consider genetic architectures with and without pleiotropy and epistasis. We also model neutral marker loci on an explicit genetic map as the 2 populations diverge and apply FST outlier approaches to determine the extent to which quantitative trait loci (QTL) are detectable. Our results show, under a wide range of conditions, that only a small number of QTL are typically responsible for most of the trait divergence between populations, even when inheritance is highly polygenic. We find that the loci making the largest contributions to trait divergence tend to be detectable outliers. These loci also make the largest contributions to within-population genetic variance. The addition of pleiotropy reduces the extent to which quantitative traits can evolve independently but does not reduce the efficacy of outlier scans. The addition of epistasis, however, reduces the mean FST values for causative QTL, making these loci more difficult, but not impossible, to detect in outlier scans.



2021 ◽  
Author(s):  
Shruti Mahajan ◽  
Abhisek Chakraborty ◽  
Titas Sil ◽  
Vineet K Sharma

During the ongoing COVID-19 pandemic Tinospora cordifolia also known as Giloy gained immense popularity and use due to its immunity-boosting function and anti-viral properties. T. cordifolia is among the most important medicinal plants that has numerous therapeutic applications in health due to the production of a diverse array of secondary metabolites. Therefore, to gain genomic insights into the medicinal properties of T. cordifolia, the first genome sequencing was carried out using 10x Genomics linked read technology and the draft genome assembly comprised of 1.01 Gbp. This is also the first genome sequenced from the plant family Menispermaceae. We also performed the first genome size estimation for T. cordifolia and was found to be 1.13 Gbp. The deep sequencing of transcriptome from the leaf tissue was also performed followed by transcriptomic analysis to gain insights into the gene expression and functions. The genome and transcriptome assemblies were used to construct the gene set in T. cordifolia that resulted in 19,474 coding gene sequences. Further, the phylogenetic position of T. cordifolia was also determined through the construction of a genome-wide phylogenetic tree using 35 other dicot species and one monocot species as an outgroup species.



2017 ◽  
Author(s):  
Anna Marcionetti ◽  
Victor Rossier ◽  
Joris A. M. Bertrand ◽  
Glenn Litsios ◽  
Nicolas Salamin

AbstractClownfishes (or anemonefishes) form an iconic group of coral reef fishes, particularly known for their mutualistic interaction with sea anemones. They are characterized by particular life history traits, such as a complex social structure and mating system involving sequential hermaphroditism, coupled with an exceptionally long lifespan. Additionally, clownfishes are considered to be one of the rare group to have experienced an adaptive radiation in the marine environment.Here, we assembled and annotated the first genome of a clownfish species, the tomato clownfish (Amphiprion frenatus). We obtained a total of 17,801 assembled scaffolds, containing a total of 26,917 genes. The completeness of the assembly and annotation was satisfying, with 96.5% of the Actinopterygii BUSCOs (Benchmarking Universal Single-Copy Orthologs) being retrieved in A. frenatus assembly. The quality of the resulting assembly is comparable to other bony fish assemblies.This resource is valuable for the advancing of studies of the particular life-history traits of clownfishes, as well as being useful for population genetic studies and the development of new phylogenetic markers. It will also open the way to comparative genomics. Indeed, future genomic comparison among closely related fishes may provide means to identify genes related to the unique adaptations to different sea anemone hosts, as well as better characterize the genomic signatures of an adaptive radiation.



2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Bhavani Manivannan ◽  
Niranjana Mahalingam ◽  
Sudhir Jadhao ◽  
Amrita Mishra ◽  
Pravin Nilawe ◽  
...  

We present the draft genome assembly of an extensively drug-resistant (XDR) Pseudomonas aeruginosa strain isolated from a patient with a history of genito urinary tuberculosis. The draft genome is 7,022,546 bp with a G+C content of 65.48%. It carries 7 phage genomes, genes for quorum sensing, biofilm formation, virulence, and antibiotic resistance.



Author(s):  
Dominic A. Stoll ◽  
Nicolas Danylec ◽  
Christina Grimmler ◽  
Sabine E. Kulling ◽  
Melanie Huch

The strain Adlercreutzia caecicola DSM 22242T (=CCUG 57646T=NR06T) was taxonomically described in 2013 and named as Parvibacter caecicola Clavel et al. 2013. In 2018, the name of the strain DSM 22242T was changed to Adlercreutzia caecicola (Clavel et al. 2013) Nouioui et al. 2018 due to taxonomic investigations of the closely related genera Adlercreutzia, Asaccharobacter and Enterorhabdus within the phylum Actinobacteria . However, the first whole draft genome of strain DSM 22242T was published by our group in 2019. Therefore, the genome was not available within the study of Nouioui et al. (2018). The results of the polyphasic approach within this study, including phenotypic and biochemical analyses and genome-based taxonomic investigations [genome-wide average nucleotide identity (gANI), alignment fraction (AF), average amino acid identity (AAI), percentage of orthologous conserved proteins (POCP) and genome blast distance phylogeny (GBDP) tree], indicated that the proposed change of the name Parvibacter caecicola to Adlercreutzia caecicola was not correct. Therefore, it is proposed that the correct name of Adlercreutzia caecicola (Clavel et al. 2013) Nouioui et al. 2018 strain DSM 22242T is Parvibacter caecicola Clavel et al. 2013.



2012 ◽  
Vol 71 (6) ◽  
pp. 895-906 ◽  
Author(s):  
Luming Yang ◽  
Dal-Hoe Koo ◽  
Yuhong Li ◽  
Xuejiao Zhang ◽  
Feishi Luan ◽  
...  


2021 ◽  
Author(s):  
Zhijin Liu ◽  
Xuekun Qian ◽  
Ziming Wang ◽  
Huamei Wen ◽  
Ling Han ◽  
...  

Abstract BcakgroundLoaches of the superfamily Cobitoidea (Cypriniformes, Nemacheilidae) are small elongated bottom-dwelling freshwater fishes with several barbels near the mouth. The genus Oreonectes with 18 currently recognized species contains representatives for all three key stages of the evolutionary process (a surface-dwelling lifestyle, facultative cave persistence, and permanent cave dwelling). Some Oreonectes species show typical cave dwelling-related traits, such as partial or complete leucism and regression of the eyes, rendering them as suitable study objects of micro-evolution. Genome information of Oreonectes species is therefore an indispensable resource for research into the evolution of cavefishes.ResultsHere we assembled the genome sequence of O. shuilongensis, a surface-dwelling species, using an integrated approach that combined PacBio single-molecule real-time sequencing and Illumina X-ten paired-end sequencing. Based on in total 50.9 Gb of sequencing data, our genome assembly from Canu and Pilon spans approximately 515.64 Mb (estimated coverage of 100 ×), containing 803 contigs with N50 values of 5.58 Mb. 25,247 protein-coding genes were predicted, of which 95.65% have been functionally annotated. We also performed genome re-sequencing of three additional cave-dwelling Oreonectes fishes. Twenty-nine pseudogenes annotated using DAVID showed significant enrichment for the GO terms of “eye development” and “retina development in camera-type eye”. It is presumed that these pseudogenes might lead to eye degeneration of semi/complete cave-dwelling Oreonectes species. Furthermore, Mc1r (melanocortin-1 receptor) is a pseudogenization by a deletion in O. daqikongensis, likely blocking biosynthesis of melanin and leading to the albino phenotype.ConclusionsWe here report the first draft genome assembly of Oreonectes fishes, which is also the first genome reference for Cobitidea fishes. Pseudogenization of genes related to body color and eye development may be responsible for loss of pigmentation and vision deterioration in cave-dwelling species. This genome assembly will contribute to the study of the evolution and adaptation of fishes within Oreonectes and beyond (Cobitidea).



Author(s):  
Jian-Zhi Huang ◽  
Chih-Peng Lin ◽  
Ting-Chi Cheng ◽  
Ya-Wen Huang ◽  
Yi-Jung Tsai ◽  
...  

Phalaenopsis orchid is an important potted flower with high economic value around the world. We report the 3.1 Gb draft genome assembly of an important winter flowering Phalaenopsis ‘KHM190’ cultivar. We generated 89.5 Gb RNA-seq and 113 million sRNA-seq reads to use these data to identify 41,153 protein-coding genes and 188 miRNA families. We also generated a draft genome for Phalaenopsis pulcherrima ‘B8802’, a summer flowering species, via resequencing. Comparison of genome data between the two Phalaenopsis cultivars allowed the identification of 691,532 single-nucleotide polymorphisms. In this study, we reveal the key role of PhAGL6b in the regulation of flower organ development involves alternative splicing. We also show gibberellin pathways that regulate the expression of genes control flowering time during the stage in reproductive phase change induced by cool temperature. Our work should contribute a valuable resource for the flowering control, flower architecture development, and breeding of the Phalaenopsis orchids.



2021 ◽  
Author(s):  
Roger Huerlimann ◽  
Jeff A Cowley ◽  
Nicholas M Wade ◽  
Yinan Wang ◽  
Naga Kasinadhuni ◽  
...  

Shrimp are a valuable aquaculture species globally; however, disease remains a major hindrance to shrimp aquaculture sustainability and growth. Mechanisms mediated by endogenous viral elements (EVEs) have been proposed as a means by which shrimp that encounter a new virus start to accommodate rather than succumb to infection over time. However, evidence on the nature of such EVEs and how they mediate viral accommodation is limited. More extensive genomic data on Penaeid shrimp from different geographical locations should assist in exposing the diversity of EVEs. In this context, reported here is a PacBio Sequel-based draft genome assembly of an Australian black tiger shrimp (Penaeus monodon) inbred for one generation. The 1.89 Gbp draft genome is comprised of 31,922 scaffolds (N50: 496,398 bp) covering 85.9% of the projected genome size. The genome repeat content (61.8% with 30% representing simple sequence repeats) is almost the highest identified for any species. The functional annotation identified 35,517 gene models, of which 25,809 were protein-coding and 17,158 were annotated using interproscan. Scaffold scanning for specific EVEs identified an element comprised of a 9,045 bp stretch of repeated, inverted and jumbled genome fragments of Infectious hypodermal and hematopoietic necrosis virus (IHHNV) bounded by a repeated 591/590 bp host sequence. As only near complete linear ~4 kb IHHNV genomes have been found integrated in the genome of P. monodon previously, its discovery has implications regarding the validity of PCR tests designed to specifically detect such linear EVE types. The existence of conjoined inverted IHHNV genome fragments also provides a means by which hairpin dsRNAs could be expressed and processed by the shrimp RNA interference (RNAi) machinery.



2017 ◽  
Author(s):  
Timothy H Webster ◽  
Greer A. Dolby ◽  
Melissa Wilson Sayres ◽  
Kenro Kusumi

Exogenous sequence contamination presents a challenge in first-draft genomes because it can lead to non-contiguous, chimeric assembled sequences. This can mislead downstream analyses reliant on synteny, such as linkage-based analyses. Recently, the Mojave Desert Tortoise (Gopherus agassizii) draft genome was published as a resource to advance conservation efforts for the threatened species and discover more about chelonian biology and evolution. Here, we illustrate steps taken to improve the desert tortoise draft genome by removing contaminating sequences—actions that are typically carried out after the initial release of a draft genome assembly. We used information from NCBI’s Vecscreen output to remove intra-scaffold contamination and trim heading and trailing Ns. We then reordered and renamed scaffolds, and transferred the gene annotation onto this assembly. Finally, we describe the tools developed for this pipeline, freely available on Github (https://github.com/thw17/G_agassizii_reference_update), which facilitate post-assembly processing of other draft genomes. The new gopAga1.1 genome has an N50 of 251 KB, L50 of 2592 scaffolds, and its annotation retains 17,201 of the original 20,172 genes that were unaffected by the scaffold processing.



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