@article {78, title = {Accurate circular consensus long-read sequencing improves variant detection and assembly of a human genome.}, journal = {Nat Biotechnol}, volume = {37}, year = {2019}, month = {2019 Oct}, pages = {1155-1162}, abstract = {

The DNA sequencing technologies in use today produce either highly accurate short reads or less-accurate long reads. We report the optimization of circular consensus sequencing (CCS) to improve the accuracy of single-molecule real-time (SMRT) sequencing (PacBio) and generate highly accurate (99.8\%) long high-fidelity (HiFi) reads with an average length of 13.5 kilobases (kb). We applied our approach to sequence the well-characterized human HG002/NA24385 genome and obtained precision and recall rates of at least 99.91\% for single-nucleotide variants (SNVs), 95.98\% for insertions and deletions <50 bp (indels) and 95.99\% for structural variants. Our CCS method matches or exceeds the ability of short-read sequencing to detect small variants and structural variants. We estimate that 2,434 discordances are correctable mistakes in the {\textquoteright}genome in a bottle{\textquoteright} (GIAB) benchmark set. Nearly all (99.64\%) variants can be phased into haplotypes, further improving variant detection. De novo genome assembly using CCS reads alone produced a contiguous and accurate genome with a contig N50 of >15 megabases (Mb) and concordance of 99.997\%, substantially outperforming assembly with less-accurate long reads.

}, issn = {1546-1696}, doi = {10.1038/s41587-019-0217-9}, author = {Wenger, Aaron M and Peluso, Paul and Rowell, William J and Chang, Pi-Chuan and Hall, Richard J and Concepcion, Gregory T and Ebler, Jana and Fungtammasan, Arkarachai and Kolesnikov, Alexey and Olson, Nathan D and T{\"o}pfer, Armin and Alonge, Michael and Mahmoud, Medhat and Qian, Yufeng and Chin, Chen-Shan and Phillippy, Adam M and Schatz, Michael C and Myers, Gene and DePristo, Mark A and Ruan, Jue and Marschall, Tobias and Sedlazeck, Fritz J and Zook, Justin M and Li, Heng and Koren, Sergey and Carroll, Andrew and Rank, David R and Hunkapiller, Michael W} } @article {80, title = {Ancestral Admixture Is the Main Determinant of Global Biodiversity in Fission Yeast.}, journal = {Mol Biol Evol}, volume = {36}, year = {2019}, month = {2019 09 01}, pages = {1975-1989}, abstract = {

Mutation and recombination are key evolutionary processes governing phenotypic variation and reproductive isolation. We here demonstrate that biodiversity within all globally known strains of Schizosaccharomyces pombe arose through admixture between two divergent ancestral lineages. Initial hybridization was inferred to have occurred \~{}20-60 sexual outcrossing generations ago consistent with recent, human-induced migration at the onset of intensified transcontinental trade. Species-wide heritable phenotypic variation was explained near-exclusively by strain-specific arrangements of alternating ancestry components with evidence for transgressive segregation. Reproductive compatibility between strains was likewise predicted by the degree of shared ancestry. To assess the genetic determinants of ancestry block distribution across the genome, we characterized the type, frequency, and position of structural genomic variation using nanopore and single-molecule real-time sequencing. Despite being associated with double-strand break initiation points, over 800 segregating structural variants exerted overall little influence on the introgression landscape or on reproductive compatibility between strains. In contrast, we found strong ancestry disequilibrium consistent with negative epistatic selection shaping genomic ancestry combinations during the course of hybridization. This study provides a detailed, experimentally tractable example that genomes of natural populations are mosaics reflecting different evolutionary histories. Exploiting genome-wide heterogeneity in the history of ancestral recombination and lineage-specific mutations sheds new light on the population history of S. pombe and highlights the importance of hybridization as a creative force in generating biodiversity.

}, issn = {1537-1719}, doi = {10.1093/molbev/msz126}, author = {Tusso, Sergio and Nieuwenhuis, Bart P S and Sedlazeck, Fritz J and Davey, John W and Jeffares, Daniel C and Wolf, Jochen B W} } @article {54, title = {Atlas-CNV: a validated approach to call single-exon CNVs in the eMERGESeq gene panel.}, journal = {Genet Med}, volume = {21}, year = {2019}, month = {2019 Sep}, pages = {2135-2144}, abstract = {

PURPOSE: To provide a validated method to confidently identify exon-containing copy-number variants (CNVs), with a low false discovery rate (FDR), in targeted sequencing data from a clinical laboratory with particular focus on single-exon CNVs.

METHODS: DNA sequence coverage data are normalized within each sample and subsequently exonic CNVs are identified in a batch of samples, when the target log ratio of the sample to the batch median exceeds defined thresholds. The quality of exonic CNV calls is assessed by C-scores (Z-like scores) using thresholds derived from gold standard samples and simulation studies. We integrate an ExonQC threshold to lower FDR and compare performance with alternate software (VisCap).

RESULTS: Thirteen CNVs were used as a truth set to validate Atlas-CNV and compared with VisCap. We demonstrated FDR reduction in validation, simulation, and 10,926 eMERGESeq samples without sensitivity loss. Sixty-four multiexon and 29 single-exon CNVs with high C-scores were assessed by~Multiplex Ligation-dependent Probe Amplification (MLPA).

CONCLUSION: Atlas-CNV is validated as a method to identify exonic CNVs in targeted sequencing data generated in the clinical laboratory. The ExonQC and C-score assignment can reduce FDR (identification of targets with high variance) and improve calling accuracy of single-exon CNVs respectively. We propose guidelines and criteria to identify high confidence single-exon CNVs.

}, issn = {1530-0366}, doi = {10.1038/s41436-019-0475-4}, author = {Chiang, Theodore and Liu, Xiuping and Wu, Tsung-Jung and Hu, Jianhong and Sedlazeck, Fritz J and White, Simon and Schaid, Daniel and Andrade, Mariza de and Jarvik, Gail P and Crosslin, David and Stanaway, Ian and Carrell, David S and Connolly, John J and Hakonarson, Hakon and Groopman, Emily E and Gharavi, Ali G and Fedotov, Alexander and Bi, Weimin and Leduc, Magalie S and Murdock, David R and Jiang, Yunyun and Meng, Linyan and Eng, Christine M and Wen, Shu and Yang, Yaping and Muzny, Donna M and Boerwinkle, Eric and Salerno, William and Venner, Eric and Gibbs, Richard A} } @article {37, title = {Accurate detection of complex structural variations using single-molecule sequencing.}, journal = {Nat Methods}, volume = {15}, year = {2018}, month = {2018 06}, pages = {461-468}, abstract = {

Structural variations are the greatest source of genetic variation, but they remain poorly understood because of technological limitations. Single-molecule long-read sequencing has the potential to dramatically advance the field, although high error rates are a challenge with existing methods. Addressing this need, we introduce open-source methods for long-read alignment (NGMLR; https://github.com/philres/ngmlr ) and structural variant identification (Sniffles; https://github.com/fritzsedlazeck/Sniffles ) that provide unprecedented sensitivity and precision for variant detection, even in repeat-rich regions and for complex nested events that can have substantial effects on human health. In several long-read datasets, including healthy and cancerous human genomes, we discovered thousands of novel variants and categorized systematic errors in short-read approaches. NGMLR and Sniffles can automatically filter false events and operate on low-coverage data, thereby reducing the high costs that have hindered the application of long reads in clinical and research settings.

}, keywords = {DNA Mutational Analysis, Genome, Human, Genomics, High-Throughput Nucleotide Sequencing, Humans, Sequence Analysis, DNA}, issn = {1548-7105}, doi = {10.1038/s41592-018-0001-7}, author = {Sedlazeck, Fritz J and Rescheneder, Philipp and Smolka, Moritz and Fang, Han and Nattestad, Maria and von Haeseler, Arndt and Schatz, Michael C} }