Publications by authors named "Evan Eichler"

Introduction: , a protein kinase located on human chromosome 21, plays a role in postembryonic neuronal development and degeneration. Alterations to have been consistently associated with cognitive functioning and neurodevelopmental disorders (e.g.

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Segmental duplications (SDs) contribute significantly to human disease, evolution and diversity but have been difficult to resolve at the sequence level. We present a population genetics survey of SDs by analyzing 170 human genome assemblies (from 85 samples representing 38 Africans and 47 non-Africans) in which the majority of autosomal SDs are fully resolved using long-read sequence assembly. Excluding the acrocentric short arms and sex chromosomes, we identify 173.

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Rare diseases are collectively common, affecting approximately one in twenty individuals worldwide. In recent years, rapid progress has been made in rare disease diagnostics due to advances in DNA sequencing, development of new computational and experimental approaches to prioritize genes and genetic variants, and increased global exchange of clinical and genetic data. However, more than half of individuals suspected to have a rare disease lack a genetic diagnosis.

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Down syndrome (DS) or trisomy 21 (T21) is present in a significant number of children and adults around the world and is associated with cognitive and medical challenges. Through research, the T21 Research Society (T21RS), established in 2014, unites a worldwide community dedicated to understanding the impact of T21 on biological systems and improving the quality of life of people with DS across the lifespan. T21RS hosts an international conference every two years to support collaboration, dissemination, and information sharing for this goal.

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Heterozygous deleterious null alleles and specific missense variants in the DNA-binding domain of the ETS2 repressor factor (ERF) cause craniosynostosis, while the recurrent p.(Tyr89Cys) missense variant is associated with Chitayat syndrome. Exome and whole transcriptome sequencing revealed the ERF de novo in-frame indel c.

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Motivation: Centromeres are chromosomal regions historically understudied with sequencing technologies due to their repetitive nature and short-read mapping limitations. However, recent improvements in long-read sequencing allow for the investigation of complex regions of the genome at the sequence and epigenetic levels.

Results: Here, we present Centromere Dip Region (CDR)-Finder: a tool to identify regions of hypomethylation within the centromeres of high-quality, contiguous genome assemblies.

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The naked mole-rat (NMR; ) is a eusocial subterranean rodent with a highly unusual set of physiological traits that has attracted great interest amongst the scientific community. However, the genetic basis of most of these traits has not been elucidated. To facilitate our understanding of the molecular mechanisms underlying NMR physiology and behaviour, we generated a long-read chromosomal-level genome assembly of the NMR.

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The human genome is packaged within a three-dimensional (3D) nucleus and organized into structural units known as compartments, topologically associating domains (TADs), and loops. TAD boundaries, separating adjacent TADs, have been found to be well conserved across mammalian species and more evolutionarily constrained than TADs themselves. Recent studies show that structural variants (SVs) can modify 3D genomes through the disruption of TADs, which play an essential role in insulating genes from outside regulatory elements' aberrant regulation.

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Centromeres are chromosomal regions historically understudied with sequencing technologies due to their repetitive nature and short-read mapping limitations. However, recent improvements in long-read sequencing allowed for the investigation of complex regions of the genome at the sequence and epigenetic levels. Here, we present Centromere Dip Region (CDR)-Finder: a tool to identify regions of hypomethylation within the centromeres of high-quality, contiguous genome assemblies.

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Article Synopsis
  • The study investigates the molecular mechanisms of neurodevelopmental disorders (NDDs) linked to genetic variants, finding that de novo variants are particularly common in female patients with developmental delay.
  • Researchers created a deficient zebrafish model that displayed various behavioral and developmental issues, including reduced survival rates and social interaction deficits.
  • The findings suggest that the deficiency affects neural stem cell development and mRNA stability, leading to disrupted Notch signaling and neurogenesis, while also identifying potential therapeutic strategies to address these issues.
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Purpose: Rapid genetic testing in the critical care setting may guide diagnostic evaluation, direct therapies, and help families and care providers make informed decisions about goals of care. We tested whether a simplified DNA extraction and library preparation process would enable us to perform ultra-rapid assessment of genetic risk for a Mendelian condition, based on information from an affected sibling, using long-read genome sequencing and targeted analysis.

Methods: Following extraction of DNA from cord blood and rapid library preparation, genome sequencing was performed on an Oxford Nanopore PromethION.

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Previous studies suggested that the copy number of the human salivary amylase gene, , correlates with starch-rich diets. However, evolutionary analyses are hampered by the absence of accurate, sequence-resolved haplotype variation maps. We identified 30 structurally distinct haplotypes at nucleotide resolution among 98 present-day humans, revealing that the coding sequences of copies are evolving under negative selection.

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Some toddlers with autism spectrum disorder (ASD) have mild social symptoms and developmental improvement in skills, but for others, symptoms and abilities are moderately or even severely affected. Those with profound autism have the most severe social, language, and cognitive symptoms and are at the greatest risk of having a poor developmental outcome. The little that is known about the underlying biology of this important profound autism subtype, points clearly to embryonic dysregulation of proliferation, differentiation and neurogenesis.

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Haplotype information is crucial for biomedical and population genetics research. However, current strategies to produce de novo haplotype-resolved assemblies often require either difficult-to-acquire parental data or an intermediate haplotype-collapsed assembly. Here, we present Graphasing, a workflow which synthesizes the global phase signal of Strand-seq with assembly graph topology to produce chromosome-scale de novo haplotypes for diploid genomes.

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Article Synopsis
  • * It achieves a high level of completeness, closing 92% of previous assembly gaps and fully assembling complex regions, including 1,852 complex structural variants and 1,246 human centromeres.
  • * The findings lead to significant improvements in genotyping accuracy and enable the detection of over 26,000 structural variants per sample, enhancing the potential for future disease association research.
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  • * The 1000 Genomes Project and Oxford Nanopore Technologies are working together to produce LRS data from at least 800 samples to enhance the identification of genetic variations and better understand human genetic diversity.
  • * Initial analysis of 100 samples shows high accuracy in detecting genetic variants, including structural variants that disrupt gene function, and provides valuable data for the clinical genetics community to advance research on pathogenic variations.
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Motivation: We are now in the era of being able to routinely generate highly contiguous (near telomere-to-telomere) genome assemblies of human and nonhuman species. Complex structural variation and regions of rapid evolutionary turnover are being discovered for the first time. Thus, efficient and informative visualization tools are needed to evaluate and directly observe structural differences between two or more genomes.

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The 10q11.22 chromosomal region is a duplication-rich interval of the human genome and one of the last to be fully assembled. It carries copy number-variable genes associated with intellectual disability, bipolar disorder, and obesity.

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Article Synopsis
  • - This study examines the link between rare variants in the cullin-3 ubiquitin ligase (CUL3) gene and neurodevelopmental disorders (NDDs), gathering data from multiple centers to explore genetic mutations and their clinical impacts.
  • - Researchers identified 37 individuals with CUL3 variants, most of which result in loss-of-function (LoF), leading to intellectual disabilities and possibly autistic traits; specific mechanisms affecting protein stability were also investigated.
  • - The findings enhance the understanding of NDDs associated with CUL3 mutations, suggesting that LoF variants are the main cause, which could help inform future diagnostics and treatment strategies.
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Using five complementary short- and long-read sequencing technologies, we phased and assembled >95% of each diploid human genome in a four-generation, 28-member family (CEPH 1463) allowing us to systematically assess mutations (DNMs) and recombination. From this family, we estimate an average of 192 DNMs per generation, including 75.5 single-nucleotide variants (SNVs), 7.

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Article Synopsis
  • 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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is a primate-specific gene family that has expanded in the human lineage and has been implicated in neuronal progenitor proliferation and expansion of the frontal cortex. The gene family and its expression have been challenging to investigate because it is embedded in high-identity and highly variable segmental duplications. We sequenced and assembled the gene family using long-read sequencing data from 34 humans and 11 nonhuman primate species.

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This preliminary study sought to assess biomarkers of attention using electroencephalography (EEG) and eye tracking in two ultra-rare monogenic populations associated with autism spectrum disorder (ASD). Relative to idiopathic ASD (n = 12) and neurotypical comparison (n = 49) groups, divergent attention profiles were observed for the monogenic groups, such that individuals with DYRK1A (n = 9) exhibited diminished auditory attention condition differences during an oddball EEG paradigm whereas individuals with SCN2A (n = 5) exhibited diminished visual attention condition differences noted by eye gaze tracking when viewing social interactions. Findings provide initial support for alignment of auditory and visual attention markers in idiopathic ASD and neurotypical development but not monogenic groups.

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Article Synopsis
  • MUC5AC and MUC5B are special proteins that help protect our bodies by catching germs and helping us clear mucus!
  • Researchers studied the differences in these proteins by looking at DNA from humans and primates and found that MUC5B is mostly the same in humans, while MUC5AC has many variations!
  • The study also showed that people from East Asia have unique versions of the MUC5AC protein that might have helped them in survival, while another version is more common in Europeans!
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Segmental duplications (SDs) contribute significantly to human disease, evolution, and diversity yet have been difficult to resolve at the sequence level. We present a population genetics survey of SDs by analyzing 170 human genome assemblies where the majority of SDs are fully resolved using long-read sequence assembly. Excluding the acrocentric short arms, we identify 173.

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