BOL: Related items

Metassembler: merging and optimizing de novo genome assemblies

Rahul Nayak — Tue, 08 May 2018 04:52:33 -0500

Metassembler combines multiple whole genome de novo assemblies into a combined consensus assembly using the best segments of the individual assemblies.

Genome assembly projects typically run multiple algorithms in an attempt to find the single best assembly, although those assemblies often have complementary, if untapped, strengths and weaknesses. We present our metassembler algorithm that merges multiple assemblies of a genome into a single superior sequence.

Address of the bookmark: https://sourceforge.net/projects/metassembler/?source=directory

ARC: pipeline which facilitates iterative, reference guided de novo assemblies

Jit — Thu, 26 Jul 2018 09:20:26 -0500

ARC is a pipeline which facilitates iterative, reference guided de novo assemblies with the intent of:

Reducing time in analysis and increasing accuracy of results by only considering those reads which should assemble together.
Reducing/removing reference bias as compared to mapping based approaches.

The software is designed to work in situations where a whole-genome assembly is not the objective, but rather when the researcher wishes to assemble discreet 'targets' contained within next-generation shotgun sequence data. ARC decomplexifies the traditionally difficult problem of assembly by breaking the reads into small, manageable subsets which can then be assembled quickly and efficiently in parallel. Applications include those in which the researcher wishes to de novo assemble specific content and a set of semi-similar reference targets is available to initialize the assembly process.

https://ibest.github.io/ARC/

Address of the bookmark: https://ibest.github.io/ARC/

Wtdbg2: a de novo sequence assembler for long noisy reads produced by PacBio or Oxford Nanopore

Neel — Fri, 19 Oct 2018 08:48:43 -0500

Wtdbg2 is a de novo sequence assembler for long noisy reads produced by PacBio or Oxford Nanopore Technologies (ONT). It assembles raw reads without error correction and then builds the consensus from intermediate assembly output. Wtdbg2 is able to assemble the human and even the 32Gb Axolotl genome at a speed tens of times faster than CANU and FALCONwhile producing contigs of comparable base accuracy.

Address of the bookmark: https://github.com/ruanjue/wtdbg2

Flye: Fast and accurate de novo assembler for single molecule sequencing reads

Rahul Nayak — Sat, 06 Jul 2019 03:48:22 -0500

Flye is a de novo assembler for single molecule sequencing reads, such as those produced by PacBio and Oxford Nanopore Technologies. It is designed for a wide range of datasets, from small bacterial projects to large mammalian-scale assemblies. The package represents a complete pipeline: it takes raw PB / ONT reads as input and outputs polished contigs. Flye also includes a special mode for metagenome assembly.

Address of the bookmark: https://github.com/fenderglass/Flye

3D de novo assembly (3D DNA) pipeline

Jit — Sun, 02 Feb 2020 13:41:55 -0600

For a detailed description of the pipeline and how it integrates with other tools designed by the Aiden Lab see Genome Assembly Cookbook on http://aidenlab.org/assembly.

For the original version of the pipeline and to reproduce the Hs2-HiC and the AaegL4 genomes reported in (Dudchenko et al., Science, 2017) see the original commit.

For the detailed description of the merge section see https://github.com/theaidenlab/AGWG-merge.

Address of the bookmark: https://github.com/theaidenlab/3d-dna

Meraculous: De Novo Genome Assembly with Short Paired-End Reads

Jit — Tue, 07 Nov 2017 04:36:10 -0600

We describe a new algorithm, meraculous, for whole genome assembly of deep paired-end short reads, and apply it to the assembly of a dataset of paired 75-bp Illumina reads derived from the 15.4 megabase genome of the haploid yeast Pichia stipitis. More than 95% of the genome is recovered, with no errors; half the assembled sequence is in contigs longer than 101 kilobases and in scaffolds longer than 269 kilobases. Incorporating fosmid ends recovers entire chromosomes. Meraculous relies on an efficient and conservative traversal of the subgraph of the k-mer (deBruijn) graph of oligonucleotides with unique high quality extensions in the dataset, avoiding an explicit error correction step as used in other short-read assemblers. A novel memory-efficient hashing scheme is introduced. The resulting contigs are ordered and oriented using paired reads separated by ∼280 bp or ∼3.2 kbp, and many gaps between contigs can be closed using paired-end placements. Practical issues with the dataset are described, and prospects for assembling larger genomes are discussed.

Address of the bookmark: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3158087/

ALE: Assembly Likelihood Estimator

BioStar — Wed, 08 Mar 2023 01:39:33 -0600

Just import the assembly, bam and ALE scores. You can convert the .ale file to a set of .wig files with ale2wiggle.py and IGV can read those directly. Depending on your genome size you may want to convert the .wig files to the BigWig format.

Address of the bookmark: https://github.com/sc932/ALE

Bioinformatics Programme Officer @ International Centre for Genetic ICGEB Engineering and Biotechnology

Fri, 23 Nov 2018 03:50:16 -0600

The following vacancies are available in the DBT Apex Biotechnology Information project at ICGEB, New Delhi, India. These positions are available for a period of approx. two years, however, initial appointment offer will be for 6 months, which will be extended based on performance of work. Salaries will be offered as per DBT, educational qualification and experience. Depending on requirements, selected candidates may be required to work on location from the Department of Biotechnology, New Delhi. Shortlisted candidates will be invited for an interview at ICGEB. Only the selected candidates will be informed individually. No TA/DA or accommodation will be offered to the candidates attending the interview.

4 Programme Officer 1
5 Technical Research Assistant 1

Minimum Educational Qualification, desirable experience and expected duties:

4: The applicants should be Postgraduates with experience in Data collection and Statistics, especially in Biotechnology-related data.

Expected duties: Collection of Biotechnology related information from India, to facilitate the Apex BTIC experts committee review of programmes at centres and R&D programs funded by DBT.

5: The applicants should be Postgraduates in Science with experience in Bioinformatics-related projects.
Expected duties: The candidates will assist the senior staff of the centre in daily activities and help in the preparation of the Annual Training Calendar, seminar and training podcasts/videos, repository of training material and Apex BTIC Newsletter.

Interested candidates should submit their full, updated Curriculum Vitae with a detailed description of relevant experience, along with two references by December 14th, 2018, addressed to, The Chairperson, DBT- Apex BTIC, ICGEB, Aruna Asaf Ali Marg, New Delhi 110067, Email: abtic@icgeb.res.in, kindly write “Application for DBT Apex BTIC vacancy” in the subject of the email or envelope, if sending by post.

Advertisement: http://www.icgeb.org/tl_files/Vacancies/dbt-abtic-vac-annmntrevsk.pdf

Genetic basis of tail-loss evolution

LEGE — Tue, 04 Mar 2025 12:12:36 -0600

The paper "On the genetic basis of tail-loss evolution in humans and apes (https://www.nature.com/articles/s41586-024-07095-8)", published in Nature, investigates the genetic mechanisms that led to the loss of tails in humans and apes. The study suggests that a specific genetic mutation, involving the insertion of an Alu element (a type of transposable DNA sequence), played a critical role in the evolutionary transition from tailed primates to tailless hominoids.

Key Findings of the Study:

Alu Insertion and Tail Loss:
The researchers discovered an Alu-mediated genetic change in a common ancestor of modern apes and humans. This change disrupted the normal function of a gene involved in tail development, leading to the suppression of tail formation.
Gene Disruption Mechanism:
The Alu insertion was found within a regulatory region of the TBXT gene (also known as T or Brachyury), which is crucial for tail development in vertebrates. This insertion likely altered the gene's expression patterns, leading to tail reduction over evolutionary time.
Functional Evidence from Model Organisms:
To test their hypothesis, the researchers introduced similar genetic modifications in mice. The modified mice exhibited shortened or absent tails, supporting the idea that the identified mutation played a role in tail loss in hominoids.
Evolutionary Implications:
The findings suggest that small, random genomic changes—such as transposable element insertions—can have profound effects on body morphology. This study provides evidence that mobile DNA elements (like Alu) can drive major evolutionary transitions.
Relevance to Human Evolution:
Understanding the genetic basis of tail loss helps in reconstructing the evolutionary history of hominins (the lineage that includes humans and our extinct relatives). It also sheds light on how genetic variations contribute to anatomical diversity among primates.

Significance of the Study:

This research highlights the role of transposable elements in shaping evolutionary traits and provides a concrete genetic explanation for a defining characteristic of humans and great apes. It also demonstrates how mutations in regulatory regions of developmental genes can lead to significant anatomical changes.

Flanker

Rahul Nayak — Sat, 27 Feb 2021 22:04:53 -0600

Flanker, a Python package which performs alignment-free clustering of gene flanking sequences in a consistent format, allowing investigation of mobile genetic elements (MGEs) without prior knowledge of their structure. Flanker can be flexibly parameterised to finetune outputs by characterising upstream and downstream regions separately and investigating variable lengths of flanking sequence.

Address of the bookmark: https://github.com/wtmatlock/flanker