Background: Genome-wide comparisons of populations are widely used to explore the patterns of nucleotide diversity and sequence divergence to provide knowledge on how natural selection and genetic drift affect the genome. In this study we have compared whole-genome sequencing data from Atlantic and Pacific herring, two sister species that diverged about 2 million years ago, to explore the pattern of genetic differentiation between the two species.
Results: The genome comparison of the two species revealed high genome-wide differentiation but with islands of remarkably low genetic differentiation, as measured by an F analysis. However, the low F observed in these islands is not caused by low interspecies sequence divergence (d) but rather by exceptionally high estimated intraspecies nucleotide diversity (π). These regions of low differentiation and elevated nucleotide diversity, termed high-diversity regions in this study, are not enriched for repeats but are highly enriched for immune-related genes. This enrichment includes genes from both the adaptive immune system, such as immunoglobulin, T-cell receptor and major histocompatibility complex genes, as well as a substantial number of genes with a role in the innate immune system, e.g. novel immune-type receptor, tripartite motif and tumor necrosis factor receptor genes. Analysis of long-read based assemblies from two Atlantic herring individuals revealed extensive copy number variation in these genomic regions, indicating that the elevated intraspecies nucleotide diversities were partially due to the cross-mapping of short reads.
Conclusions: This study demonstrates that copy number variation is a characteristic feature of immune trait loci in herring. Another important implication is that these loci are blind spots in classical genome-wide screens for genetic differentiation using short-read data, not only in herring, likely also in other species harboring qualitatively similar variation at immune trait loci. These loci stood out in this study because of the relatively high genome-wide baseline for F values between Atlantic and Pacific herring.
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http://dx.doi.org/10.1186/s12864-024-10380-5 | DOI Listing |
Recent single-cell experiments that measure copy numbers of over 40 proteins in individual cells at different time points [time-stamped snapshot (TSS) data] exhibit cell-to-cell variability. Because the same cells cannot be tracked over time, TSS data provide key information about the time-evolution of protein abundances that could yield mechanisms that underlie signaling kinetics. We recently developed a generalized method of moments (GMM) based approach that estimates parameters of mechanistic models using TSS data.
View Article and Find Full Text PDFChanges in the copy number of large genomic regions, termed copy number variations (CNVs), contribute to important phenotypes in many organisms. CNVs are readily identified using conventional approaches when present in a large fraction of the cell population. However, CNVs that are present in only a few genomes across a population are often overlooked but important; if beneficial under specific conditions, a de novo CNV that arises in a single genome can expand during selection to create a larger population of cells with novel characteristics.
View Article and Find Full Text PDFbioRxiv
December 2024
Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire, UK.
Conjugation, the major driver of the spread of antimicrobial resistance genes, relies on a conjugation pilus for DNA transfer. Conjugative pili, such as the F-pilus, are dynamic tubular structures, composed of a polymerized pilin, that mediate the initial donor-recipient interactions, a process known as mating pair formation (MPF). IncH are low-copy-number plasmids, traditionally considered broad host range, which are found in bacteria infecting both humans and animals.
View Article and Find Full Text PDFIntroduction: Structural variants (SVs) of the nebulin gene ( ), including intragenic duplications, deletions, and copy number variation of the triplicate region, are an established cause of recessively inherited nemaline myopathies and related neuromuscular disorders. Large deletions have been shown to cause dominantly inherited distal myopathies. Here we provide an overview of 35 families with muscle disorders caused by such SVs in .
View Article and Find Full Text PDFAtheroscler Plus
March 2025
Department of Laboratory Medicine, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
Background And Aims: Familial hypercholesterolemia (FH) and other disorders with similar features are common genetic disorders that remain underdiagnosed and undertreated, due in part to the cost of screening. The aim of this study was to design and implement a whole gene targeted NGS panel for the molecular diagnosis of FH and statin intolerance with an emphasis on high quality variant calling, including copy number analysis.
Methods: A whole gene panel for hybridisation-based short read NGS was designed for the dominant FH-genes low density lipoprotein receptor (), apolipoprotein B (APOB), proproteinconvertas subtilisin/kexin type 9 (PCSK9), apolipoprotein E (APOE) and the recessive FH-genes low density lipoprotein receptor adaptor protein 1 (), ATP binding cassette subfamily member 5/8 (ABCG5/8) and lipase A, lysosomal acid type (), as well as solute carrier organic anion transporter family member 1B1 (), not an FH gene but linked to statin intolerance.
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