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Hartmann, U.

Publications and source records attributed to Hartmann, U..

2 recordsLinked to original sources

TinkerHap - A Novel Read-Based Phasing Algorithm with Integrated Multi-Method Support for Enhanced Accuracy

Phasing, the assignment of alleles to their respective parental chromosomes, is fundamental to studying genetic variation and identifying disease-causing variants. Traditional approaches, including statistical, pedigree-based, and read-based phasing, face challenges such as limited accuracy for rare variants, reliance on external reference panels, and constraints in regions with sparse genetic variation. To address these limitations, we developed TinkerHap, a novel and unique phasing algorithm that integrates a read-based phaser, based on a pairwise distance-based unsupervised classification, with external phased data, such as statistical or pedigree phasing. We evaluated TinkerHaps performance against other phasing algorithms using 1,040 parent-offspring trios from the UK Biobank (Illumina short-reads) and GIAB Ashkenazi trio (PacBio long-reads). TinkerHaps read-based phaser alone achieved higher phasing accuracies than all other algorithms with 95.1% for short-reads (second best: 94.8%) and 97.5% for long-reads (second best: 95.5%). Its hybrid approach further enhanced short-read performance to 96.3% accuracy and was able to phase 99.5% of all heterozygous sites. TinkerHap also extended haplotype block sizes to a median of 79,449 base-pairs for long-reads (second best: 68,303 bp) and demonstrated higher accuracy for both SNPs and indels. This combination of a robust read-based algorithm and hybrid strategy makes TinkerHap a uniquely powerful tool for genomic analyses.

genomics↗

The secreted neuronal signal Spock1 regulates the blood-brain barrier

The blood-brain barrier (BBB) is a unique set of properties of the brain vasculature which severely restricts its permeability to proteins and small molecules. Classic chick-quail chimera studies showed that these properties are not intrinsic to the brain vasculature but rather are induced by surrounding neural tissue. Here we identify Spock1 as a candidate neuronal signal for regulating BBB permeability in zebrafish and mice. Mosaic genetic analysis shows that neuronally-expressed Spock1 is cell non-autonomously required for a functional BBB. Leakage in spock1 mutants is associated with altered extracellular matrix (ECM), increased endothelial transcytosis, and altered pericyte-endothelial interactions. Furthermore, a single dose of recombinant SPOCK1 partially restores BBB function in spock1 mutants by quenching gelatinase activity and restoring vascular expression of BBB genes including mcamb. These analyses support a model in which neuronally secreted Spock1 induces BBB properties by altering the ECM, thereby regulating pericyte-endothelial interactions and downstream vascular gene expression. One-Sentence SummarySpock1 is a signal secreted by neurons that induces barrier properties in the brain vasculature

neuroscience↗