The assembly of long reads from Pacific Biosciences and Oxford Nanopore Technologies typically requires resource-intensive error-correction and consensus-generation steps to obtain high-quality ...assemblies. We show that the error-correction step can be omitted and that high-quality consensus sequences can be generated efficiently with a SIMD-accelerated, partial-order alignment-based, stand-alone consensus module called Racon. Based on tests with PacBio and Oxford Nanopore data sets, we show that Racon coupled with miniasm enables consensus genomes with similar or better quality than state-of-the-art methods while being an order of magnitude faster.
The SIFT (sorting intolerant from tolerant) algorithm helps bridge the gap between mutations and phenotypic variations by predicting whether an amino acid substitution is deleterious. SIFT has been ...used in disease, mutation and genetic studies, and a protocol for its use has been previously published with Nature Protocols. This updated protocol describes SIFT 4G (SIFT for genomes), which is a faster version of SIFT that enables practical computations on reference genomes. Users can get predictions for single-nucleotide variants from their organism of interest using the SIFT 4G annotator with SIFT 4G's precomputed databases. The scope of genomic predictions is expanded, with predictions available for more than 200 organisms. Users can also run the SIFT 4G algorithm themselves. SIFT predictions can be retrieved for 6.7 million variants in 4 min once the database has been downloaded. If precomputed predictions are not available, the SIFT 4G algorithm can compute predictions at a rate of 2.6 s per protein sequence. SIFT 4G is available from http://sift-dna.org/sift4g.
Abstract
Singapore’s National Flower,
Papilionanthe
(
Ple
.) Miss Joaquim ‘Agnes’ (PMJ) is highly prized as a horticultural flower from the Orchidaceae family. A combination of short-read sequencing, ...single-molecule long-read sequencing and chromatin contact mapping was used to assemble the PMJ genome, spanning 2.5 Gb and 19 pseudo-chromosomal scaffolds. Genomic resources and chemical profiling provided insights towards identifying, understanding and elucidating various classes of secondary metabolite compounds synthesized by the flower. For example, presence of the anthocyanin pigments detected by chemical profiling coincides with the expression of
ANTHOCYANIN SYNTHASE (ANS)
, an enzyme responsible for the synthesis of the former. Similarly, the presence of vandaterosides (a unique class of glycosylated organic acids with the potential to slow skin aging) discovered using chemical profiling revealed the involvement of glycosyltransferase family enzymes candidates in vandateroside biosynthesis. Interestingly, despite the unnoticeable scent of the flower, genes involved in the biosynthesis of volatile compounds and chemical profiling revealed the combination of oxygenated hydrocarbons, including traces of linalool, beta-ionone and vanillin, forming the scent profile of PMJ. In summary, by combining genomics and biochemistry, the findings expands the known biodiversity repertoire of the Orchidaceae family and insights into the genome and secondary metabolite processes of PMJ.
Protein database search is one of the fundamental problems in bioinformatics. For decades, it has been explored and solved using different exact and heuristic approaches. However, exponential growth ...of data in recent years has brought significant challenges in improving already existing algorithms. BLAST has been the most successful tool for protein database search, but is also becoming a bottleneck in many applications. Due to that, many different approaches have been developed to complement or replace it. In this article, we present SWORD, an efficient protein database search implementation that runs 8-16 times faster than BLAST in the sensitive mode and up to 68 times faster in the fast and less accurate mode. It is designed to be used in nearly all database search environments, but is especially suitable for large databases. Its sensitivity exceeds that of BLAST for majority of input datasets and provides guaranteed optimal alignments.
Sword is freely available for download from https://github.com/rvaser/sword
robert.vaser@fer.hr and mile.sikic@fer.hr
Supplementary data are available at Bioinformatics online.
Brucella
, an extremely diverse but yet genetically highly homogenous genus of bacteria, has been a puzzle for scientists for many decades. These bacteria remain a prominent public health issue, ...particularly in the Balkan region. Correctly identifying and understanding the pathogen is a vital step in the epidemiology and epizootiology of any bacteria. Identification can be challenging, especially in the case of zoonotic species. This study aimed to implement fourth-generation sequencing in the typing of 11
Brucella suis
strains kept in our archive and to compare this method to the classical and non-sequencing based molecular methods used to date. Classical biotyping is highly subjective and gave inconclusive results for 3 strains. Molecular methods used were multiplex PCR and RFLP methods since no one method can identify both species and biovar which is vital in the case of
Brucella suis
infections. Species and biovars of all the strains were successfully confirmed and in concordance with biotyping results. Oxford Nanopore long-read sequencing was used on a MinION device for next-generation sequencing (NGS). Various algorithms were implemented for genome assembly and BioNumerics 8.0 software was used for MLST identification and analysis. MLST 21 was used for biovar identification and epidemiological comparison of tested strains. The assembled genomes were 3,2 Mb in size and assembled into two chromosomes. MLST 21 analysis placed our strains into species and biovar clusters in concordance with other molecular tests used. To the extent of our knowledge, this is the first documented use of long-read sequencing in
Brucella suis
identification in this region. We conclude that bacteriological biotyping is outdated and host-specific identification in this genus is incorrect and that molecular characterisation is always the safer, faster and more suitable option. MinION sequencing proved to be a strong, accessible solution for species determination. Future study is required to determine how detailed genome information it can give, considering the error rate.
Rod
Brucella
biološki je iznimno raznolik, ali genetski vrlo homogen rod bakterija te je već desetljećima znanstvenicima nepoznanica. Ove bakterije su veliki javno-zdravstveni problem, a osobito na Balkanu. Pravilno prepoznavanje i razumijevanje patogena ključan je korak u epidemiologiji i epizootiologiji bilo koje bakterijske vrste, čija identifikacija može biti izazovna, osobito u slučaju zoonotskih vrsta. Cilj je ovog rada bio implementirati sekvenciranje četvrte generacije u tipizaciji 11 sojeva
Brucella suis
koje se čuvaju u našoj arhivi te ovu metodu usporediti s klasičnim i molekularnim metodama koje se trenutačno primjenjuju, a ne zasnivaju se na sekvenciranju. Klasično je biotipiziranje vrlo subjektivno i dalo je podvojene rezultate za 3 soja. Od molekularnih metoda koristili smo višestruku lančanu reakciju polimerazom (engl. Polymerase Chain Reaction, PCR) i polimorfizam duljine restrikcijskih fragmenata (engl. Restriction Fragment Lenght Polymorphism, RFLP) budući da niti jedna od metoda ne može zasebno identificirati i vrstu i biovar, a što je važno u slučaju
Brucella suis
infekcije. Vrsta i biovar svih sojeva uspješno su potvrđene i u skladu s rezultatima biotipizacije. Sekvenciranje sljedeće generacije (engl. Next Generation Sequencing, NGS) provodili smo na Oxford Nanopore MinION uređaju koji sekvencira duge lance DNK. Za sastavljanje genoma rabljeni su različiti algoritmi, a za identifikaciju i analizu rezultata MLST-a korišten je softver BioNumerics 8.0. MLST 21 je korišten za identifikaciju biovara i epidemiološku usporedbu ispitivanih sojeva. Genomi su bili veličine 3,2 Mb i sastavljeni u dva kromosoma. Analiza MLST 21 smjestila je naše sojeve u vrsne i biovarne skupine u skladu s drugim korištenim molekularnim testovima. Koliko je nama poznato, ovo je prva dokumentirana uporaba sekvenciranja dugih lanaca DNK u identifikaciji
Brucella suis
u jugoistočnoj Europi. Zaključujemo da je bakteriološka biotipizacija zastarjela i da je identifikacija biovara u ovom rodu, ovisno o domaćinu, netočna te da je molekularna karakterizacija uvijek sigurnija, brža i prikladnija opcija. MinION sekvenciranje pokazalo se kao vrlo pristupačno rješenje za određivanje vrste i biovara
Brucella suis
. Daljnja su istraživanja potrebna da bi se ustvrdilo koliko detaljne informacije o genomu može dati, imajući u vidu značajniji postotak pogreške prilikom sekvenciranja.
Yet another de novo genome assembler Vaser, Robert; Sikic, Mile
2019 11th International Symposium on Image and Signal Processing and Analysis (ISPA),
2019-Sept.
Conference Proceeding
Odprti dostop
Advances in sequencing technologies have pushed the limits of genome assemblies beyond imagination. The sheer amount of long read data that is being generated enables the assembly for even the ...largest and most complex organism for which efficient algorithms are needed. We present a new tool, called Ra, for de novo genome assembly of long uncorrected reads. It is a fast and memory friendly assembler based on sequence classification and assembly graphs, developed with large genomes in mind. It is freely available at https://github.com/lbcbsci/ra.
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