Josipa Lipovac
@jlipovac.bsky.social
62 followers 87 following 13 posts
PhD student at FER, University of Zagreb | Bioinformatics | Metagenome analysis | Genome assembly
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jlipovac.bsky.social
I am happy to share our new preprint introducing MADRe - a pipeline for Metagenomic Assembly-Driven Database Reduction, enabling accurate and computationally efficient strain-level metagenomic classification.

🔗https://www.biorxiv.org/content/10.1101/2025.05.12.653324v1
1/9
Reposted by Josipa Lipovac
sinamajidian.bsky.social
Excited to share our EvANI benchmarking workflow, published in Briefings in Bioinformatics doi.org/10.1093/bib/...
Computing average nucleotide identity (ANI) is neither conceptually nor computationally trivial. Its definition has evolved over years, with different meanings and assumptions (1/5)
Figure 1(A) ANI quantifies the similarity between two genomes. ANI can be defined as the number of aligned positions where the two aligned bases are identical, divided by the total number of aligned bases. Historically, ANI was calculated using a single gene family for multiple sequence alignment. Another approach finds orthologous genes between two genomes and reports the average similarity between their CDSs. This method was later extended to whole-genome alignment by identifying local alignments and excluding supplementary alignments with lower similarity. (B) Different ANI tools employ various approaches in calculating ANI values. ANIm, OrthoANI, and FastANI use aligners to identify homologous regions, whereas Mash uses k-mer hashing to estimate similarities. Only alignments with higher similarity represented by green arrows are included in ANI calculations, while red arrows, corresponding to paralogs, are excluded. (C) The proposed benchmarking method evaluates the performance of different tools using both real and simulated data. It assumes that more distantly related species on the phylogenetic tree should have lower ANI similarities. This is measured by calculating the statistics of Spearman rank correlation. We expect a negative correlation between ANI and the tree distance (scatter plot on the right).
https://academic.oup.com/bib/article/doi/10.1093/bib/bbaf267/8160681
Reposted by Josipa Lipovac
zaminiqbal.bsky.social
Sometimes you meet absolutely incredible bioinfo-magicians.
It was a huge privilege when @shenwei356.bsky.social
joined our group for a year on an @embl.org sabbatical.
While here, he developed a new way of aligning to
millions of bacteria, called LexicMap 1/n
www.nature.com/articles/s41...
Efficient sequence alignment against millions of prokaryotic genomes with LexicMap - Nature Biotechnology
LexicMap uses a fixed set of probes to efficiently query gene sequences for fast and low-memory alignment.
www.nature.com
Reposted by Josipa Lipovac
jimshaw.bsky.social
Preprint out for myloasm, our new nanopore / HiFi metagenome assembler!

Nanopore's getting accurate, but

1. Can this lead to better metagenome assemblies?
2. How, algorithmically, to leverage them?

with co-author Max Marin @mgmarin.bsky.social, supervised by Heng Li @lh3lh3.bsky.social

1 / N
biorxiv-bioinfo.bsky.social
High-resolution metagenome assembly for modern long reads with myloasm https://www.biorxiv.org/content/10.1101/2025.09.05.674543v1
Reposted by Josipa Lipovac
rayanchikhi.bsky.social
🌎👩‍🔬 For 15+ years biology has accumulated petabytes (million gigabytes) of🧬DNA sequencing data🧬 from the far reaches of our planet.🦠🍄🌵

Logan now democratizes efficient access to the world’s most comprehensive genetics dataset. Free and open.

doi.org/10.1101/2024...
Reposted by Josipa Lipovac
contaminatedsci.bsky.social
Our high-precision metagenomic strain caller, PHLAME, is now published in Cell Reports!! www.cell.com/cell-reports...

PHLAME works on tough sample types -- including those with coexisting strains of a species and low depth.
jlipovac.bsky.social
Proud to share our work on the first complete genome of an Indian individual - now on bioRxiv! 😄
Reposted by Josipa Lipovac
biorxiv-bioinfo.bsky.social
Campolina: A Deep Neural Framework for Accurate Segmentation of Nanopore Signals https://www.biorxiv.org/content/10.1101/2025.07.08.663658v1
Reposted by Josipa Lipovac
pierrepeterlongo.bsky.social
📜 Excited to share insights from our recent paper: "Kaminari: a resource-frugal index for approximate colored k-mer queries". The study aims to efficiently identify documents containing a query string, focusing on DNA strings. www.biorxiv.org/content/10.1... 🧬 🖥️ 1/8
jlipovac.bsky.social
Thanks Roland! It’s good to mention here that Hairsplitter is also part of it 😄
Reposted by Josipa Lipovac
zaminiqbal.bsky.social
This looks cool from @jlipovac.bsky.social ! Strain-level metag assignment; first use EM +mapping to shrink your ref db, then do read classification
www.biorxiv.org/content/10.1...
Overview of pipeline. Map reads to NCBI database of references, use EM to choose a minimal set, then use mapping info to do read classification
jlipovac.bsky.social
A key feature of MADRe is its focus on organisms with sufficient abundance to be assembled.
While low-abundance strains may be underrepresented, this trade-off significantly reduces false-positive identifications, a common issue in strain-level metagenomics.
8/9
jlipovac.bsky.social
We evaluated MADRe on both real and simulated datasets and observed:
✅ Comparable or improved accuracy over existing tools
✅ Clearer and more realistic abundance profiles
✅ Substantial reductions in runtime and memory usage
7/9
jlipovac.bsky.social
While assembly is often considered computationally expensive, we demonstrate that MADRe, by combining assembly with contig-level mapping, is more efficient than directly mapping large volumes of reads to a full reference database. 6/9
jlipovac.bsky.social
To complete the pipeline, MADRe maps reads to the reduced reference database and applies a second round of probabilistic reassignment.
This enhances classification sensitivity and filters false-positive identifications, enabling precise strain-level profiling. 5/9
jlipovac.bsky.social
This reduction identifies candidate genomes present in the sample.
However, this step alone does not eliminate all false positives and does not provide accurate abundance estimates. 4/9
jlipovac.bsky.social
MADRe begins by assembling the metagenomic sample and mapping the resulting contigs - often representing collapsed strains - to a (large) reference database.
Using EM-based read reassignment and info about strain collapses, we construct reduced database. 3/9
jlipovac.bsky.social
Strain-level classification requires large reference databases, especially when there is no prior knowledge about sample composition.
However, mapping reads to such large databases is computationally expensive and often impractical at scale. 2/9
jlipovac.bsky.social
I am happy to share our new preprint introducing MADRe - a pipeline for Metagenomic Assembly-Driven Database Reduction, enabling accurate and computationally efficient strain-level metagenomic classification.

🔗https://www.biorxiv.org/content/10.1101/2025.05.12.653324v1
1/9
Reposted by Josipa Lipovac
biorxiv-bioinfo.bsky.social
High-quality metagenome assembly from nanopore reads with nanoMDBG https://www.biorxiv.org/content/10.1101/2025.04.22.649928v1
Reposted by Josipa Lipovac
brinda.eu
A decade ago, we had thousands of bacterial genomes. Now, we have millions. How to scale computational methods?

Our paper in @naturemethods.bsky.social answers this: use evolutionary history to guide compression and search.

rdcu.be/eg4OA

w/ @baym.lol, @zaminiqbal.bsky.social et al. 🧵1/
Reposted by Josipa Lipovac