Biology subjects

Nolte, N. F.

Publications and source records attributed to Nolte, N. F..

3 recordsLinked to original sources

bioRxiv2026

LongPolyASE: An end-to-end framework for allele-specific gene and isoform analysis in polyploids using long-read RNA-seq

MotivationLong-read RNA-seq and phased reference genomes enable haplotype-resolved gene and isoform expression analysis. While methods and tools exist for diploid organisms, analysis tools for polyploids are lacking. ResultsWe developed an end-to-end framework for allele-specific gene and isoform analysis in polyploids with three components: Syntelogfinder identifies syntenic genes in phased assemblies; longrnaseq quantifies transcripts, discovers novel isoforms, and performs quality control of long-read RNA-seq; and PolyASE analyzes differential allelic expression, differential isoform usage between conditions, and structural differences in major isoforms between haplotypes. We demonstrate the use of the framework on diploid rice and autotetraploid potato. Availability and ImplementationSyntelogfinder and longrnaseq are implemented in Nextflow and available on GitHub. PolyASE is a Python package available on PyPI. The framework is fully documented and tutorials are provided. ContactNadja.nolte.franziska@nib.si Supplementary informationSupplementary data are available online and on Zenodo.

bioinformatics↗

bioRxiv2025

The promise of long-read RNA-seq: reducing bias in analyses of allele imbalance

Inaccurate allele and gene expression counts due to map bias and genome ambiguity lead to high false positive and false negative rates in studies of allelic imbalance. We demonstrate that long read RNA-seq and straightforward quality control measures can be used to reduce bias in allele counts in case studies from four species: Drosophila melanogaster, a diploid insect; Solanum tuberosum, an autopolyploid plant; Pongo abelii, a highly heterozygous diploid primate, and Homo sapiens. We recommend 1) mapping to a personalized genome to increase the number of allele assignments 2) tracking multimapping reads and tuning mapping parameters to ensure accurate allele and gene expression counts and 3) evaluating apparent extreme allele bias to identify errors in genome assembly and annotation. We show that these steps can be executed in a straightforward manner and recommend tools for each step.

genetics↗

bioRxiv2025

Multiparent Recombinant Inbred lines crossed to a tester provide novel insights into sources of cis and trans regulation of gene expression

We propose crossing multi-parent recombinant-inbred-lines (RILs) to a common tester and measuring allele specific gene expression in the offspring. Testing whether allelic imbalance between two RIL x Tester crosses is equal, is a test of cis or trans depending on the RIL alleles compared. The study design also enables to separate two sources of trans variation, genetic and environmental, detected via interactions with cis effects. Examining these components of regulatory variation, we demonstrate this approach in a long-read RNA-seq experiment in female abdominal tissue at two time points in Drosophila melanogaster. Among the 40% of all loci that show evidence of genetic variation in cis, trans effects due to the environment are detectable in 31% of loci and trans effects due to genetic background are detectable in 19% of loci with little overlap in sources of trans variation. The loci identified in this study are associated with loci previously reported to exhibit genetic variation in gene expression in a range of tissues and large population samples, suggesting that there is consistent variation for genetic regulation of gene expression. We show that eleven loci in a QTL for thermotolerance, previously shown to differ in expression based on temperature, have evidence for regulation of gene expression regardless of the environment, including Cpr67B, a cuticular protein suggesting a potential functional role for standing variation in gene expression. This study provides a blueprint for efficiently identifying regulatory variation in gene expression, as the tester design maximizes cis variation and enables the efficient assessment of all pairs of RIL alleles relative to the tester, a much smaller study compared to the pairwise direct assessment.

genetics↗