This study examines the feasibility of employing raw two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC–ToF-MS) data for the purpose of human scent identity verification. Unlike techniques that require expert-driven identification of compounds, our framework transforms each GC×GC–ToF-MS sample into a multi-channel image. A comprehensive assessment has been conducted on ten feature-embedding methods, and five spatial-alignment strategies.The evaluation is performed on a newly assembled dataset of 252 individuals, comprising 2,528 raw samples and aggregating around 7.5 TB of data. On our dataset, the best method reaches ≈ 53% true positive rate at a 5% false positive rate without explicit spatial registration. Although this performance is below that of well-established biometrics (e.g., iris verification), the results demonstrate the feasibility of raw-odor verification for scenarios where direct line-of-sight or cooperation may be limited and suggest that, for our acquisition/drift regime, explicit registration is not required to reach the best performance.Code and dataset on github.com.

Motivation: The NCBI database contains mitochondrial DNA (mtDNA) genomes from numerous species. We investigated the presence and locations of inverted repeat sequences (IRs) in these mtDNA sequences, which are known to be important for regulating nuclear genomes. Results: IRs were identified in mtDNA in all species. IR lengths and frequencies correlate with evolutionary age and the greatest variability was detected in subgroups of plants and fungi and the lowest variability in mammals. IR presence is non-random and evolutionary favoured. The frequency of IRs generally decreased with IR length, but not for IRs 24 or 30 bp long, which are 1.5 times more abundant. IRs are enriched in sequences from the replication origin, followed by D-loop, stem-loop and miscellaneous sequences, pointing to the importance of IRs in regulatory regions of mitochondrial DNA. Availability and implementation: Data were produced using Palindrome analyser, freely available on the web at http://bioinformatics.ibp.cz. Contact: [email protected]. Supplementary information: Supplementary data are available at Bioinformatics online.