Publications by authors named "Rachel O'Neill"

The marsupial moles are arguably Australia's most enigmatic marsupials. Almost indistinguishable from placental (eutherian) moles, they provide a striking example of convergent evolution. Exploring the genome of the southern marsupial mole, we provide insights into its unusual biology.

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  • The MAPK genes are important for gonadal differentiation in eutherian mammals, and this study investigates their role in marsupials, specifically the tammar wallaby.
  • The researchers used a MAPK inhibitor, SB202190, to study its effects on gonads and found it reduced levels of key genes SOX9 and AMH in XY gonads.
  • The study concludes that the MAPK pathway is involved in testis differentiation in marsupials, similar to its role in eutherian mammals.
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T cell receptor (TCR) sensitivity to peptide-major histocompatibility complex (MHC) dictates T cell fate. Canonical models of TCR sensitivity cannot be fully explained by transcriptional regulation. In this work, we identify a posttranscriptional regulatory mechanism of TCR sensitivity that guides alternative splicing of TCR signaling transcripts through an evolutionarily ultraconserved poison exon (PE) in the RNA-binding protein (RBP) TRA2β in mouse and human.

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Great apes have maintained a stable karyotype with few large-scale rearrangements; in contrast, gibbons have undergone a high rate of chromosomal rearrangements coincident with rapid centromere turnover. Here we characterize assembled centromeres in the Eastern hoolock gibbon, (HLE), finding a diverse group of transposable elements (TEs) that differ from the canonical alpha satellites found across centromeres of other apes. We find that HLE centromeres contain a CpG methylation centromere dip region, providing evidence this epigenetic feature is conserved in the absence of satellite arrays; nevertheless, we report a variety of atypical centromeric features, including protein-coding genes and mismatched replication timing.

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  • X chromosome inactivation (XCI) is an epigenetic phenomenon where one X chromosome in females is silenced, differing between eutherian (random silencing) and marsupial mammals (always paternal silencing).
  • In eutherians, the inactive X shows high DNA methylation at key sites, while marsupials have lower methylation levels on the paternal X.
  • The study focused on the tammar wallaby's X chromosome during sperm development, finding that the paternal X has a DNA methylation profile similar to the inactive X in female tissues, suggesting it may serve as an imprint for paternal XCI in marsupials.
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  • The study presents detailed genomes of six ape species, achieving high accuracy and complete sequencing of all their chromosomes.
  • It addresses complex genomic regions, leading to enhanced understanding of evolutionary relationships among these species.
  • The findings will serve as a crucial resource for future research on human evolution and our closest ape relatives.
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Telomere-to-telomere (T2T) assemblies reveal new insights into the structure and function of the previously 'invisible' parts of the genome and allow comparative analyses of complete genomes across entire clades. We present here an open collaborative effort, termed the 'Ruminant T2T Consortium' (RT2T), that aims to generate complete diploid assemblies for numerous species of the Artiodactyla suborder Ruminantia to examine chromosomal evolution in the context of natural selection and domestication of species used as livestock.

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  • Apes have two sex chromosomes: the essential Y chromosome for male reproduction and the X chromosome necessary for both reproduction and cognition, with differences in mating patterns affecting their function.
  • Studying these chromosomes is challenging due to their repetitive structures, but researchers created gapless assemblies for five great apes and one lesser ape to explore their evolutionary complexities.
  • The Y chromosomes are highly variable and undergo significant changes compared to the more stable X chromosomes, and this research can provide insights into human evolution and aid in the conservation of endangered ape species.
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  • - The eastern quoll, an endangered marsupial from Australia, has lost its mainland populations and now only exists on two islands, leading to efforts for captive breeding and re-establishment on the mainland.
  • - Researchers created a high-quality reference genome for the eastern quoll, aiding in genetic management and providing insight into its demographic history, which shows signs of long-term decline starting in the late Pleistocene.
  • - The study also discovered a genetic deletion at the ASIP locus that may explain the color differences in fur between the eastern quoll and the closely related Tasmanian devil.
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  • Scorpions are an ancient group of arachnids, over 400 million years old, and one of the first land-dwelling animals, but research on their evolution is limited due to the lack of genomic data.
  • This study used advanced sequencing techniques to create the first detailed chromosome-level genome assembly for the desert hairy scorpion, Hadrurus arizonensis, yielding a genome size of 2.23 Gb and reorganizing the data into nine chromosomes.
  • The assembly identified a high number of protein-coding genes and complete arthropod orthologs, making it a valuable resource for understanding scorpion evolution, arachnid relationships, and for future genomic studies.
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  • DNA methylation is vital for regulating transposable elements and gene expression, influencing plant stress responses; traditional quantification methods are often inaccurate.
  • Advances in long-read sequencing, particularly using Oxford Nanopore Technologies, allow for more accurate real-time detection of methylation across various contexts in plants.
  • This research generated methylation profiles for two maple species, revealing significant patterns related to transposable elements and helping understand gene family dynamics and nutrient stress responses in angiosperms.
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Chromosome reshuffling events are often a foundational mechanism by which speciation can occur, giving rise to highly derivative karyotypes even amongst closely related species. Yet, the features that distinguish lineages prone to such rapid chromosome evolution from those that maintain stable karyotypes across evolutionary time are still to be defined. In this review, we summarize lineages prone to rapid karyotypic evolution in the context of Simpson's rates of evolution-tachytelic, horotelic, and bradytelic-and outline the mechanisms proposed to contribute to chromosome rearrangements, their fixation, and their potential impact on speciation events.

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  • Apes have two main sex chromosomes, X and Y, where Y is crucial for male reproduction and its deletions can lead to infertility, while X is important for both reproduction and brain function.
  • Recent advancements in genomic techniques helped researchers create complete structures of the X and Y chromosomes for multiple great ape species, allowing them to explore their evolutionary complexities.
  • Findings indicate that Y chromosomes are highly variable and undergo rapid changes due to unique genetic regions and transposable elements, while X chromosomes are more stable, highlighting differing evolutionary paths among great ape species.
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Ocean warming favors pelagic tunicates, such as salps, that exhibit increasingly frequent and rapid population blooms, impacting trophic dynamics and composition and human marine-dependent activities. Salp blooms are a result of their successful reproductive life history, alternating seasonally between asexual and sexual protogynous (i.e.

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  • Advances in affordable third-generation sequencing and bioinformatics allow for better conservation efforts by enabling the sequencing and analysis of endangered species like Juglans cinerea (butternut walnut).
  • Butternut is endangered primarily due to a deadly fungus (Ophiognomonia clavigignenti-juglandacearum) that damages the tree and leads to its decline, emphasizing the need for conservation because of its ecological and cultural importance.
  • The study includes the first reference genome for Juglans cinerea, created using advanced sequencing techniques, revealing insights into its genetic structure and challenges like reduced gene families linked to stress responses.
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The human Y chromosome has been notoriously difficult to sequence and assemble because of its complex repeat structure that includes long palindromes, tandem repeats and segmental duplications. As a result, more than half of the Y chromosome is missing from the GRCh38 reference sequence and it remains the last human chromosome to be finished. Here, the Telomere-to-Telomere (T2T) consortium presents the complete 62,460,029-base-pair sequence of a human Y chromosome from the HG002 genome (T2T-Y) that corrects multiple errors in GRCh38-Y and adds over 30 million base pairs of sequence to the reference, showing the complete ampliconic structures of gene families TSPY, DAZ and RBMY; 41 additional protein-coding genes, mostly from the TSPY family; and an alternating pattern of human satellite 1 and 3 blocks in the heterochromatic Yq12 region.

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The prevalence of highly repetitive sequences within the human Y chromosome has prevented its complete assembly to date and led to its systematic omission from genomic analyses. Here we present de novo assemblies of 43 Y chromosomes spanning 182,900 years of human evolution and report considerable diversity in size and structure. Half of the male-specific euchromatic region is subject to large inversions with a greater than twofold higher recurrence rate compared with all other chromosomes.

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The kangaroo endogenous retrovirus (KERV) was previously reported to have undergone a rapid copy number increase in the red-necked wallaby; however, the mode of amplification was left to be clarified. The present study revealed that the long terminal repeat (LTR) (0.6 kb) and internal region (2.

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The novel long non-coding RNA (lncRNA) is extraordinarily conserved in both its location (syntenic with an essential gene in anogenital patterning) and sequence. Here we show that is upregulated following the testosterone surge from the developing testis and directly interacts with positively regulating its expression. expression is suppressed by estrogen, which in turn suppresses the expression of .

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Motivation: Non-canonical (or non-B) DNA are genomic regions whose three-dimensional conformation deviates from the canonical double helix. Non-B DNA play an important role in basic cellular processes and are associated with genomic instability, gene regulation, and oncogenesis. Experimental methods are low-throughput and can detect only a limited set of non-B DNA structures, while computational methods rely on non-B DNA base motifs, which are necessary but not sufficient indicators of non-B structures.

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READY is a self-report prospective longitudinal study of deaf and hard of hearing (DHH) young people aged 16 to 19 years on entry. Its overarching aim is to explore the risk and protective factors for successful transition to adulthood. This article introduces the cohort of 163 DHH young people, background characteristics and study design.

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  • The Javan gibbon (Hylobates moloch) is an endangered species found only in western and central Java, Indonesia, making it one of the rarest gibbons.
  • Gibbons belong to the Hylobatidae family, which has four genera with varying chromosome counts from 38 to 52, though the reasons behind this variation are not well understood due to limited genomic data.
  • The study presents the first detailed genome assembly for H. moloch, utilizing various advanced sequencing techniques, providing a crucial resource for future comparative genomics research in primates.
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Alternative splicing of RNA occurs frequently in eukaryotic cells and can result in multiple protein isoforms that are nearly identical in amino acid sequence, but have unique biological roles. Moreover, the relative abundance of these unique isoforms can be correlative with diseased states and potentially used as biomarkers or therapeutic targets. However, due to high sequence similarities among isoforms, current proteomic methods are incapable of differentiating native protein isoforms derived from most alternative splicing events.

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Mobile elements and repetitive genomic regions are sources of lineage-specific genomic innovation and uniquely fingerprint individual genomes. Comprehensive analyses of such repeat elements, including those found in more complex regions of the genome, require a complete, linear genome assembly. We present a de novo repeat discovery and annotation of the T2T-CHM13 human reference genome.

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Since its initial release in 2000, the human reference genome has covered only the euchromatic fraction of the genome, leaving important heterochromatic regions unfinished. Addressing the remaining 8% of the genome, the Telomere-to-Telomere (T2T) Consortium presents a complete 3.055 billion-base pair sequence of a human genome, T2T-CHM13, that includes gapless assemblies for all chromosomes except Y, corrects errors in the prior references, and introduces nearly 200 million base pairs of sequence containing 1956 gene predictions, 99 of which are predicted to be protein coding.

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