Biology subjects

Jobling, M. A.

Publications and source records attributed to Jobling, M. A..

6 recordsLinked to original sources

bioRxiv2025

Rapid on-site universal vertebrate species identification via multi-barcode nanopore sequencing

The growing illegal wildlife trade (IWT) threatens biodiversity and is a conduit for zoonotic disease, yet its risk of detection is low. Once processed, trafficked species are difficult to identify morphologically, and currently require DNA-based approaches that are time-consuming, costly, and lab-based. There is thus a need for a rapid, cheap, on-site method for species identification. We describe VeRIF-ID (Vertebrate Rapid In-Field Identification via DNA), a method that employs simultaneous on-site nanopore sequencing of four different mitochondrial DNA barcodes. Primers were designed to produce short amplicons to aid analysis of damaged DNA, and to be effective over a broad taxonomic range of vertebrates from lamprey to chimpanzee. Validation demonstrated species-level identification in 91% of 83 tested species, and genus/tribe-level identification of the remaining species (which are also problematic with existing approaches). DNA extraction, PCR and library preparation steps were simplified and optimised so that sampling to species identification takes <3 h for a single sample. Species components are identifiable non-quantitatively in prepared mixtures of muscle tissue from up to five species, and laboratory tests of Traditional East Asian Medicine samples reveal DNA from species including critically endangered saiga antelope and black rhinoceros. In conjunction with a portable BentoLab device the necessary equipment and reagents are easily portable, and we apply the method to analyse seized bushmeat and fish samples within an airport customs zone, identifying mammal and fish species in 15 samples within 6 h. The initial equipment costs for VeRIF-ID are [~]$8K, and the cost per sample of [~]$10-48 (depending on set-up), considerably cheaper than current conventional lab-based approaches. The method requires only basic hands-on skills. Ongoing trials with potential end-users will focus on establishing forensic reporting criteria prior to casework implementation. Future development of user-friendly bioinformatic interfaces will aim to fully democratise species identification.

genetics↗

bioRxiv2024

Himalayan whole-genome sequences provide insight into population formation and adaptation

High-altitude environments pose substantial challenges for human survival and reproduction, attracting considerable attention to the demographic and adaptive histories of high-altitude populations. Previous work focused mainly on Tibetans, establishing their genetic relatedness to East Asians and their genetic adaptation to high altitude, especially at EPAS1. Here, we present 87 new whole-genome sequences from 16 Himalayan populations and the insight they provide into the genomic history of the region. We show that population structure in the Himalayas began to emerge as early as 10,000 years ago, predating archaeological evidence of permanent habitation above 2,500 meters by approximately 6,000 years. The high prevalence of the introgressed adaptive EPAS1 haplotype in all high-altitude populations today supports a shared genetic origin and its importance for survival in this region. We also identify additional selection signals in genes associated with hypoxia, physical activity, immunity and metabolism which could have facilitated adaptation to the harsh environment. Over time, increasing genetic structure led to the diverse and strongly differentiated ethnic groups observed today, most of which maintained small population sizes throughout their history or experienced severe bottlenecks. Between 6,000 and 3,000 years ago, a few uniparental lineages became predominant, likely coinciding with the advent of agriculture, although significant population growth was not observed in the Himalayas except in the Tibetans. In more recent times, we detect bidirectional gene flow between high-altitude and lowland groups, occurring on both sides of the Himalayan range. The timing of this admixture aligns with the rise and expansion of historical regional powers, particularly during the Tibetan Empire and the northern Indian Gupta Empire. In the past few centuries, migrations to the Himalayas seem to have occurred alongside conflicts and population displacements in nearby regions and show some sex bias.

genomics↗

bioRxiv2023

Defining cat mitogenome variation and accounting for numts via multiplex amplification and Nanopore sequencing

Hair shed by domestic cats is a potentially useful source of forensic evidence. Analysable hair DNA is predominantly mitochondrial, but the recent domestication history of cats means that mtDNA diversity is low. A 402-bp control region segment is usually sequenced, defining only a small number of distinct mitotypes in populations. Previously, we used a long-amplicon approach to sequence whole mitogenomes in a sample of blood DNAs from 119 UK cats, greatly increasing observed diversity and reducing random match probabilities. To exploit this variation for forensic analysis, we here describe a multiplex system that amplifies the cat mitogenome in 60 overlapping amplicons of mean length 360 bp, followed by Nanopore sequencing. Variants detected in multiplex sequence data from hair completely mirror those from long-amplicon data from blood from the same individuals. However, applying the multiplex to matched blood DNA reveals additional sequence variants which derive from the major feline nuclear mitochondrial insertion sequence (numt), which covers 7.9 kb of the 17-kb mitogenome and exists in multiple tandem copies. We use long-amplicon Nanopore sequencing to investigate numt variation in a set of cats, together with an analysis of published genome sequences, and show that numt arrays are variable in both structure and sequence, thus providing a potential source of uncertainty when nuclear DNA predominates in a sample. Forensic application of the test was demonstrated by matching hairs from a cat with skeletal remains from its putative mother, both of which shared a globally common mitotype at the control region. The random match probability (RMP) in this case with the CR 402-bp segment was 0.21 and this decreased to 0.03 when considering the whole mitogenome. The developed multiplex and sequencing approach, when applied to cat hair where nuclear DNA is scarce, can provide a reliable and highly discriminating source of forensic genetic evidence. The confounding effect of numt co-amplification in degraded samples where mixed sequences are observed can be mitigated by variant phasing, and by comparison with numt sequence diversity data, such as those presented here.

genetics↗

bioRxiv2023

Mitogenome sequences of domestic cats demonstrate lineage expansions and dynamic mutation processes in a mitochondrial minisatellite

As a population genetic tool, mitochondrial DNA is commonly divided into the [~]1-kb control region (CR), in which single nucleotide variant (SNV) diversity is relatively high, and the coding region, in which selective constraint is greater and diversity lower, but which provides an informative phylogeny. In some species, the CR contains variable tandemly repeated sequences that are understudied due to heteroplasmy. Domestic cats (Felis catus) have a recent origin and therefore traditional CR-based analysis of populations yields only a small number of haplotypes. To increase resolution we used Nanopore sequencing to analyse 119 cat mitogenomes via a long-amplicon approach. This greatly improves discrimination (from 15 to 87 distinct haplotypes) and defines a phylogeny showing similar starlike topologies within all cat haplogroups, likely reflecting post-domestication expansion. We sequenced RS2, a CR tandem array of 80-bp repeat units, placing RS2 array structures within the phylogeny and increasing overall haplotype diversity. Repeat number varies between 3 and 12 (median: 4) with over 30 different repeat unit types differing largely by SNVs. Five SNVs show evidence of independent recurrence within the phylogeny, and seven are involved in at least 11 instances of rapid spread along repeat arrays within haplogroups. In defining mitogenome variation our study provides key information for the forensic genetic analysis of cat hair evidence, and for the first time a phylogenetically informed picture of tandem repeat variation that reveals remarkably dynamic mutation processes at work in the mitochondrion.

genomics↗

bioRxiv2022

Sequencing the orthologs of human autosomal forensic short tandem repeats provides individual- and species-level identification in African great apes

BackgroundGreat apes are a global conservation concern, with anthropogenic pressures threatening their survival. Genetic analysis can be used to assess the effects of reduced population sizes and the effectiveness of conservation measures. In humans, autosomal short tandem repeats (aSTRs) are widely used in population genetics and for forensic individual identification and kinship testing. Traditionally, genotyping is length-based via capillary electrophoresis (CE), but there is an increasing move to direct analysis by massively parallel sequencing (MPS). Here we assess in African great ape DNAs the human-based ForenSeq DNA Sequencing Prep Kit, which amplifies multiple loci including 27 aSTRs, prior to sequencing via Illumina technology. We ask whether cross-species genotyping of the orthologs of these loci can provide both individual and (sub)species identification. ResultsThe Forenseq kit was used to amplify and sequence aSTRs in 52 individuals (14 chimpanzees; 4 bonobos; 16 western lowland, 6 eastern lowland, and 12 mountain gorillas). The orthologs of 24/27 human aSTRs amplified across species, and a core set of thirteen loci could be genotyped in all individuals. Genotypes were individually and (sub)species identifying. Both allelic diversity and the power to discriminate (sub)species were greater when considering STR sequences rather than allele lengths. Comparing human and African great-ape STR sequences with an orangutan outgroup showed general conservation of repeat types and allele size ranges, but variation in repeat array structures and little relationship with the known phylogeny, suggesting stochastic origins of mutations giving rise to diverse imperfect repeat arrays. Interruptions within long repeat arrays in African great apes do not appear to reduce allelic diversity, indicating a possible mutational difference to humans. ConclusionsDespite some variability in amplification success, orthologs of most human aSTRs in the ForenSeq DNA Sequencing Prep Kit can be analysed in African great apes. MPS of the orthologs of human loci provides better resolution for both individual and (sub)species identification in great apes than standard CE-based approaches, and has the further advantage that there is no need to limit the number and size ranges of analysed loci.

genetics↗

bioRxiv2019

Genetic Variation At 27 Y-STRs In Four Regions Of Bahrain

Bahrain location in the Arabian Gulf contributed to the diversity of its indigenous population descended from Christian Arabs, Persians (Zoroastrians), Jews, and Aramaic-speaking agriculturalists. The aim of this study was to examine population substructure within Bahrain using the 27 Y-STRs (short tandem repeats) in the Yfiler Plus kit and to characterize the haplotypes of 562 unrelated Bahraini nationals, sub-divided into the four geographical regions - North, Capital, South and Muharraq. Yfiler Plus provided a significant improvement over the earlier 17-locus Yfiler kit in discrimination capacity, increasing it from 77% to 87.5%, but this value differed widely between regions from 98.4% in Muharraq to 75.2% in the Northern region, an unusually low value possibly as a consequence of the very rapid expansion in population size in the last 80 years. Clusters of closely related male lineages were seen, with only 79.4% of donors displaying unique haplotypes and 59% of instances of shared haplotypes occurring within, rather than between, regions. Haplogroup prediction indicated diverse origins of the population with a predominance of haplogroups J2 and J1, both typical of the Arabian Peninsula, but also haplogroups such as B2 and E1b1a originating in Africa and H, L and R2 indicative of migration from the east. Haplogroup frequencies differed significantly between regions with J2 significantly more common in the Northern region compared with the Southern possibly as a result of differential settlement with Baharna (descended from populations in which J2 predominates) and Arabs (both indigenous and migrant Huwala who are expected to have a higher frequency of J1). Our study illustrated the importance of encompassing geographical and social variation when constructing population databases and the need for highly discriminating multiplexes where rapid expansions have occurred within tightly bounded populations.

genetics↗