1
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Xu M, Zhang X, Bai Y, Wang X, Yang J, Hu N. Mechanism study on the influences of buffer osmotic pressure on microfluidic chip-based cell electrofusion. APL Bioeng 2024; 8:026103. [PMID: 38638144 PMCID: PMC11026109 DOI: 10.1063/5.0205100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 04/04/2024] [Indexed: 04/20/2024] Open
Abstract
Cell electrofusion is a key process in many research fields, such as genetics, immunology, and cross-breeding. The electrofusion efficiency is highly dependent on the buffer osmotic pressure properties. However, the mechanism by which the buffer osmotic pressure affects cell electrofusion has not been theoretically or numerically understood. In order to explore the mechanism, the microfluidic structure with paired arc micro-cavities was first evaluated based on the numerical analysis of the transmembrane potential and the electroporation induced on biological cells when the electrofusion was performed on this structure. Then, the numerical model was used to analyze the effect of three buffer osmotic pressures on the on-chip electrofusion in terms of membrane tension and cell size. Compared to hypertonic and isotonic buffers, hypotonic buffer not only increased the reversible electroporation area in the cell-cell contact zone by 1.7 times by inducing a higher membrane tension, but also significantly reduced the applied voltage required for cell electroporation by increasing the cell size. Finally, the microfluidic chip with arc micro-cavities was fabricated and tested for electrofusion of SP2/0 cells. The results showed that no cell fusion occurred in the hypertonic buffer. The fusion efficiency in the isotonic buffer was about 7%. In the hypotonic buffer, the fusion efficiency was about 60%, which was significantly higher compared to hypertonic and isotonic buffers. The experimental results were in good agreement with the numerical analysis results.
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Affiliation(s)
- Mengli Xu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education and Bioengineering College, Chongqing University, Chongqing 400044, China
| | - Xiaoling Zhang
- School of Smart Health, Chongqing College of Electronic Engineering, Chongqing 401331, China
| | - Yaqi Bai
- Key Laboratory of Biorheological Science and Technology, Ministry of Education and Bioengineering College, Chongqing University, Chongqing 400044, China
| | - Xuefeng Wang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education and Bioengineering College, Chongqing University, Chongqing 400044, China
| | - Jun Yang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education and Bioengineering College, Chongqing University, Chongqing 400044, China
| | - Ning Hu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education and Bioengineering College, Chongqing University, Chongqing 400044, China
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2
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Ihnatovych I, Saddler RA, Sule N, Szigeti K. Translational implications of CHRFAM7A, an elusive human-restricted fusion gene. Mol Psychiatry 2024; 29:1020-1032. [PMID: 38200291 PMCID: PMC11176066 DOI: 10.1038/s41380-023-02389-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 12/08/2023] [Accepted: 12/15/2023] [Indexed: 01/12/2024]
Abstract
Genes restricted to humans may contribute to human-specific traits and provide a different context for diseases. CHRFAM7A is a uniquely human fusion gene and a negative regulator of the α7 nicotinic acetylcholine receptor (α7 nAChR). The α7 nAChR has been a promising target for diseases affecting cognition and higher cortical functions, however, the treatment effect observed in animal models failed to translate into human clinical trials. As CHRFAM7A was not accounted for in preclinical drug screens it may have contributed to the translational gap. Understanding the complex genetic architecture of the locus, deciphering the functional impact of CHRFAM7A on α7 nAChR neurobiology and utilizing human-relevant models may offer novel approaches to explore α7 nAChR as a drug target.
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Affiliation(s)
- Ivanna Ihnatovych
- Department of Neurology, State University of New York at Buffalo, 875 Ellicott St., Buffalo, NY, 14203, USA
| | - Ruth-Ann Saddler
- Department of Neurology, State University of New York at Buffalo, 875 Ellicott St., Buffalo, NY, 14203, USA
| | - Norbert Sule
- Roswell Park Comprehensive Cancer Center, 665 Elm St, Buffalo, NY, 14203, USA
| | - Kinga Szigeti
- Department of Neurology, State University of New York at Buffalo, 875 Ellicott St., Buffalo, NY, 14203, USA.
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3
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Wang B, Starr AL, Fraser HB. Cell-type-specific cis-regulatory divergence in gene expression and chromatin accessibility revealed by human-chimpanzee hybrid cells. eLife 2024; 12:RP89594. [PMID: 38358392 PMCID: PMC10942608 DOI: 10.7554/elife.89594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
Although gene expression divergence has long been postulated to be the primary driver of human evolution, identifying the genes and genetic variants underlying uniquely human traits has proven to be quite challenging. Theory suggests that cell-type-specific cis-regulatory variants may fuel evolutionary adaptation due to the specificity of their effects. These variants can precisely tune the expression of a single gene in a single cell-type, avoiding the potentially deleterious consequences of trans-acting changes and non-cell type-specific changes that can impact many genes and cell types, respectively. It has recently become possible to quantify human-specific cis-acting regulatory divergence by measuring allele-specific expression in human-chimpanzee hybrid cells-the product of fusing induced pluripotent stem (iPS) cells of each species in vitro. However, these cis-regulatory changes have only been explored in a limited number of cell types. Here, we quantify human-chimpanzee cis-regulatory divergence in gene expression and chromatin accessibility across six cell types, enabling the identification of highly cell-type-specific cis-regulatory changes. We find that cell-type-specific genes and regulatory elements evolve faster than those shared across cell types, suggesting an important role for genes with cell-type-specific expression in human evolution. Furthermore, we identify several instances of lineage-specific natural selection that may have played key roles in specific cell types, such as coordinated changes in the cis-regulation of dozens of genes involved in neuronal firing in motor neurons. Finally, using novel metrics and a machine learning model, we identify genetic variants that likely alter chromatin accessibility and transcription factor binding, leading to neuron-specific changes in the expression of the neurodevelopmentally important genes FABP7 and GAD1. Overall, our results demonstrate that integrative analysis of cis-regulatory divergence in chromatin accessibility and gene expression across cell types is a promising approach to identify the specific genes and genetic variants that make us human.
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Affiliation(s)
- Ban Wang
- Department of Biology, Stanford UniversityStanfordUnited States
| | | | - Hunter B Fraser
- Department of Biology, Stanford UniversityStanfordUnited States
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4
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Tsouris A, Brach G, Schacherer J, Hou J. Non-additive genetic components contribute significantly to population-wide gene expression variation. CELL GENOMICS 2024; 4:100459. [PMID: 38190102 PMCID: PMC10794783 DOI: 10.1016/j.xgen.2023.100459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/19/2023] [Accepted: 11/09/2023] [Indexed: 01/09/2024]
Abstract
Gene expression variation, an essential step between genotype and phenotype, is collectively controlled by local (cis) and distant (trans) regulatory changes. Nevertheless, how these regulatory elements differentially influence gene expression variation remains unclear. Here, we bridge this gap by analyzing the transcriptomes of a large diallel panel consisting of 323 unique hybrids originating from genetically divergent Saccharomyces cerevisiae isolates. Our analysis across 5,087 transcript abundance traits showed that non-additive components account for 36% of the gene expression variance on average. By comparing allele-specific read counts in parent-hybrid trios, we found that trans-regulatory changes underlie the majority of gene expression variation in the population. Remarkably, most cis-regulatory variations are also exaggerated or attenuated by additional trans effects. Overall, we showed that the transcriptome is globally buffered at the genetic level mainly due to trans-regulatory variation in the population.
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Affiliation(s)
- Andreas Tsouris
- Université de Strasbourg, CNRS, GMGM UMR, 7156 Strasbourg, France
| | - Gauthier Brach
- Université de Strasbourg, CNRS, GMGM UMR, 7156 Strasbourg, France
| | - Joseph Schacherer
- Université de Strasbourg, CNRS, GMGM UMR, 7156 Strasbourg, France; Institut Universitaire de France (IUF), Paris, France.
| | - Jing Hou
- Université de Strasbourg, CNRS, GMGM UMR, 7156 Strasbourg, France.
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5
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Fair T, Pavlovic BJ, Schaefer NK, Pollen AA. Mapping cis- and trans-regulatory target genes of human-specific deletions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.27.573461. [PMID: 38234800 PMCID: PMC10793408 DOI: 10.1101/2023.12.27.573461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Deletion of functional sequence is predicted to represent a fundamental mechanism of molecular evolution1,2. Comparative genetic studies of primates2,3 have identified thousands of human-specific deletions (hDels), and the cis-regulatory potential of short (≤31 base pairs) hDels has been assessed using reporter assays4. However, how structural variant-sized (≥50 base pairs) hDels influence molecular and cellular processes in their native genomic contexts remains unexplored. Here, we design genome-scale libraries of single-guide RNAs targeting 7.2 megabases of sequence in 6,358 hDels and present a systematic CRISPR interference (CRISPRi) screening approach to identify hDels that modify cellular proliferation in chimpanzee pluripotent stem cells. By intersecting hDels with chromatin state features and performing single-cell CRISPRi (Perturb-seq) to identify their cis- and trans-regulatory target genes, we discovered 19 hDels controlling gene expression. We highlight two hDels, hDel_2247 and hDel_585, with tissue-specific activity in the liver and brain, respectively. Our findings reveal a molecular and cellular role for sequences lost in the human lineage and establish a framework for functionally interrogating human-specific genetic variants.
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Affiliation(s)
- Tyler Fair
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Bryan J Pavlovic
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Nathan K Schaefer
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Alex A Pollen
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
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6
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Akula SK, Exposito-Alonso D, Walsh CA. Shaping the brain: The emergence of cortical structure and folding. Dev Cell 2023; 58:2836-2849. [PMID: 38113850 PMCID: PMC10793202 DOI: 10.1016/j.devcel.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 04/08/2023] [Accepted: 11/10/2023] [Indexed: 12/21/2023]
Abstract
The cerebral cortex-the brain's covering and largest region-has increased in size and complexity in humans and supports higher cognitive functions such as language and abstract thinking. There is a growing understanding of the human cerebral cortex, including the diversity and number of cell types that it contains, as well as of the developmental mechanisms that shape cortical structure and organization. In this review, we discuss recent progress in our understanding of molecular and cellular processes, as well as mechanical forces, that regulate the folding of the cerebral cortex. Advances in human genetics, coupled with experimental modeling in gyrencephalic species, have provided insights into the central role of cortical progenitors in the gyrification and evolutionary expansion of the cerebral cortex. These studies are essential for understanding the emergence of structural and functional organization during cortical development and the pathogenesis of neurodevelopmental disorders associated with cortical malformations.
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Affiliation(s)
- Shyam K Akula
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA, USA; Allen Discovery Center for Human Brain Evolution, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - David Exposito-Alonso
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA, USA; Allen Discovery Center for Human Brain Evolution, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Christopher A Walsh
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA, USA; Allen Discovery Center for Human Brain Evolution, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Chevy Chase, Maryland, USA.
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7
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Herbert AL, Allard CAH, McCoy MJ, Wucherpfennig JI, Krueger SP, Chen HI, Gourlay AN, Jackson KD, Abbo LA, Bennett SH, Sears JD, Rhyne AL, Bellono NW, Kingsley DM. The genetic basis of novel trait gain in walking fish. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.14.562356. [PMID: 37873105 PMCID: PMC10592820 DOI: 10.1101/2023.10.14.562356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
A major goal in biology is to understand how organisms evolve novel traits. Multiple studies have identified genes contributing to regressive evolution, the loss of structures that existed in a recent ancestor. However, fewer examples exist for genes underlying constructive evolution, the gain of novel structures and capabilities in lineages that previously lacked them. Sea robins are fish that have evolved enlarged pectoral fins, six mobile locomotory fin rays (legs) and six novel macroscopic lobes in the central nervous system (CNS) that innervate the corresponding legs. Here, we establish successful husbandry and use a combination of transcriptomics, CRISPR-Cas9 editing, and behavioral assays to identify key transcription factors that are required for leg formation and function in sea robins. We also generate hybrids between two sea robin species with distinct leg morphologies and use allele-specific expression analysis and gene editing to explore the genetic basis of species-specific trait diversity, including a novel sensory gain of function. Collectively, our study establishes sea robins as a new model for studying the genetic basis of novel organ formation, and demonstrates a crucial role for the conserved limb gene tbx3a in the evolution of chemosensory legs in walking fish.
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Affiliation(s)
- Amy L Herbert
- Department of Developmental Biology, Stanford University School of Medicine, Stanford CA 94305 USA
| | - Corey AH Allard
- Department of Molecular and Cellular Biology, Harvard University, Cambridge MA 02138 USA
| | - Matthew J McCoy
- Department of Pathology, Stanford University School of Medicine, Stanford CA 94305 USA
| | - Julia I Wucherpfennig
- Department of Developmental Biology, Stanford University School of Medicine, Stanford CA 94305 USA
| | - Stephanie P Krueger
- Department of Molecular and Cellular Biology, Harvard University, Cambridge MA 02138 USA
| | - Heidi I Chen
- Department of Developmental Biology, Stanford University School of Medicine, Stanford CA 94305 USA
| | | | - Kohle D Jackson
- Department of Developmental Biology, Stanford University School of Medicine, Stanford CA 94305 USA
| | - Lisa A Abbo
- Marine Biological Laboratory, Woods Hole, MA, 02543 USA
| | | | | | | | - Nicholas W Bellono
- Department of Molecular and Cellular Biology, Harvard University, Cambridge MA 02138 USA
| | - David M Kingsley
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford CA 94305 USA
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8
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Wang B, Starr AL, Fraser HB. Cell type-specific cis-regulatory divergence in gene expression and chromatin accessibility revealed by human-chimpanzee hybrid cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541747. [PMID: 37292820 PMCID: PMC10245923 DOI: 10.1101/2023.05.22.541747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Although gene expression divergence has long been postulated to be the primary driver of human evolution, identifying the genes and genetic variants underlying uniquely human traits has proven to be quite challenging. Theory suggests that cell type-specific cis-regulatory variants may fuel evolutionary adaptation due to the specificity of their effects. These variants can precisely tune the expression of a single gene in a single cell type, avoiding the potentially deleterious consequences of trans-acting changes and non-cell type-specific changes that can impact many genes and cell types, respectively. It has recently become possible to quantify human-specific cis-acting regulatory divergence by measuring allele-specific expression in human-chimpanzee hybrid cells-the product of fusing induced pluripotent stem (iPS) cells of each species in vitro. However, these cis-regulatory changes have only been explored in a limited number of cell types. Here, we quantify human-chimpanzee cis-regulatory divergence in gene expression and chromatin accessibility across six cell types, enabling the identification of highly cell type-specific cis-regulatory changes. We find that cell type-specific genes and regulatory elements evolve faster than those shared across cell types, suggesting an important role for genes with cell type-specific expression in human evolution. Furthermore, we identify several instances of lineage-specific natural selection that may have played key roles in specific cell types, such as coordinated changes in the cis-regulation of dozens of genes involved in neuronal firing in motor neurons. Finally, using novel metrics and a machine learning model, we identify genetic variants that likely alter chromatin accessibility and transcription factor binding, leading to neuron-specific changes in the expression of the neurodevelopmentally important genes FABP7 and GAD1. Overall, our results demonstrate that integrative analysis of cis-regulatory divergence in chromatin accessibility and gene expression across cell types is a promising approach to identify the specific genes and genetic variants that make us human.
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Affiliation(s)
- Ban Wang
- Department of Biology, Stanford University, Stanford, CA, USA
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9
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Fair T, Pollen AA. Genetic architecture of human brain evolution. Curr Opin Neurobiol 2023; 80:102710. [PMID: 37003107 DOI: 10.1016/j.conb.2023.102710] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 02/20/2023] [Accepted: 02/26/2023] [Indexed: 04/03/2023]
Abstract
Comparative studies of hominids have long sought to identify mutational events that shaped the evolution of the human nervous system. However, functional genetic differences are outnumbered by millions of nearly neutral mutations, and the developmental mechanisms underlying human nervous system specializations are difficult to model and incompletely understood. Candidate-gene studies have attempted to map select human-specific genetic differences to neurodevelopmental functions, but it remains unclear how to contextualize the relative effects of genes that are investigated independently. Considering these limitations, we discuss scalable approaches for probing the functional contributions of human-specific genetic differences. We propose that a systems-level view will enable a more quantitative and integrative understanding of the genetic, molecular and cellular underpinnings of human nervous system evolution.
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Affiliation(s)
- Tyler Fair
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA; Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA. https://twitter.com/@TylerFair_
| | - Alex A Pollen
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
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10
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Soto DC, Uribe-Salazar JM, Shew CJ, Sekar A, McGinty SP, Dennis MY. Genomic structural variation: A complex but important driver of human evolution. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023. [PMID: 36794631 DOI: 10.1002/ajpa.24713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 01/21/2023] [Accepted: 02/05/2023] [Indexed: 02/17/2023]
Abstract
Structural variants (SVs)-including duplications, deletions, and inversions of DNA-can have significant genomic and functional impacts but are technically difficult to identify and assay compared with single-nucleotide variants. With the aid of new genomic technologies, it has become clear that SVs account for significant differences across and within species. This phenomenon is particularly well-documented for humans and other primates due to the wealth of sequence data available. In great apes, SVs affect a larger number of nucleotides than single-nucleotide variants, with many identified SVs exhibiting population and species specificity. In this review, we highlight the importance of SVs in human evolution by (1) how they have shaped great ape genomes resulting in sensitized regions associated with traits and diseases, (2) their impact on gene functions and regulation, which subsequently has played a role in natural selection, and (3) the role of gene duplications in human brain evolution. We further discuss how to incorporate SVs in research, including the strengths and limitations of various genomic approaches. Finally, we propose future considerations in integrating existing data and biospecimens with the ever-expanding SV compendium propelled by biotechnology advancements.
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Affiliation(s)
- Daniela C Soto
- Genome Center, MIND Institute, Department of Biochemstry & Molecular Medicine, University of California, Davis, California, USA.,Integrative Genetics and Genomics Graduate Group, University of California, Davis, California, USA
| | - José M Uribe-Salazar
- Genome Center, MIND Institute, Department of Biochemstry & Molecular Medicine, University of California, Davis, California, USA.,Integrative Genetics and Genomics Graduate Group, University of California, Davis, California, USA
| | - Colin J Shew
- Genome Center, MIND Institute, Department of Biochemstry & Molecular Medicine, University of California, Davis, California, USA.,Integrative Genetics and Genomics Graduate Group, University of California, Davis, California, USA
| | - Aarthi Sekar
- Genome Center, MIND Institute, Department of Biochemstry & Molecular Medicine, University of California, Davis, California, USA.,Integrative Genetics and Genomics Graduate Group, University of California, Davis, California, USA
| | - Sean P McGinty
- Genome Center, MIND Institute, Department of Biochemstry & Molecular Medicine, University of California, Davis, California, USA.,Integrative Genetics and Genomics Graduate Group, University of California, Davis, California, USA
| | - Megan Y Dennis
- Genome Center, MIND Institute, Department of Biochemstry & Molecular Medicine, University of California, Davis, California, USA.,Integrative Genetics and Genomics Graduate Group, University of California, Davis, California, USA
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11
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Vanderhaeghen P, Polleux F. Developmental mechanisms underlying the evolution of human cortical circuits. Nat Rev Neurosci 2023; 24:213-232. [PMID: 36792753 PMCID: PMC10064077 DOI: 10.1038/s41583-023-00675-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2023] [Indexed: 02/17/2023]
Abstract
The brain of modern humans has evolved remarkable computational abilities that enable higher cognitive functions. These capacities are tightly linked to an increase in the size and connectivity of the cerebral cortex, which is thought to have resulted from evolutionary changes in the mechanisms of cortical development. Convergent progress in evolutionary genomics, developmental biology and neuroscience has recently enabled the identification of genomic changes that act as human-specific modifiers of cortical development. These modifiers influence most aspects of corticogenesis, from the timing and complexity of cortical neurogenesis to synaptogenesis and the assembly of cortical circuits. Mutations of human-specific genetic modifiers of corticogenesis have started to be linked to neurodevelopmental disorders, providing evidence for their physiological relevance and suggesting potential relationships between the evolution of the human brain and its sensitivity to specific diseases.
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Affiliation(s)
- Pierre Vanderhaeghen
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium.
| | - Franck Polleux
- Department of Neuroscience, Columbia University Medical Center, New York, NY, USA.
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
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12
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Starr AL, Gokhman D, Fraser HB. Accounting for cis-regulatory constraint prioritizes genes likely to affect species-specific traits. Genome Biol 2023; 24:11. [PMID: 36658652 PMCID: PMC9850818 DOI: 10.1186/s13059-023-02846-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 01/04/2023] [Indexed: 01/20/2023] Open
Abstract
Measuring allele-specific expression in interspecies hybrids is a powerful way to detect cis-regulatory changes underlying adaptation. However, it remains difficult to identify genes most likely to explain species-specific traits. Here, we outline a simple strategy that leverages population-scale allele-specific RNA-seq data to identify genes that show constrained cis-regulation within species yet show divergence between species. Applying this strategy to data from human-chimpanzee hybrid cortical organoids, we identify signatures of lineage-specific selection on genes related to saccharide metabolism, neurodegeneration, and primary cilia. We also highlight cis-regulatory divergence in CUX1 and EDNRB that may shape the trajectory of human brain development.
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Affiliation(s)
| | - David Gokhman
- Department of Biology, Stanford University, Stanford, CA, USA
- Present Address: Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Hunter B Fraser
- Department of Biology, Stanford University, Stanford, CA, USA.
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13
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Current advances in primate genomics: novel approaches for understanding evolution and disease. Nat Rev Genet 2023; 24:314-331. [PMID: 36599936 DOI: 10.1038/s41576-022-00554-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2022] [Indexed: 01/05/2023]
Abstract
Primate genomics holds the key to understanding fundamental aspects of human evolution and disease. However, genetic diversity and functional genomics data sets are currently available for only a few of the more than 500 extant primate species. Concerted efforts are under way to characterize primate genomes, genetic polymorphism and divergence, and functional landscapes across the primate phylogeny. The resulting data sets will enable the connection of genotypes to phenotypes and provide new insight into aspects of the genetics of primate traits, including human diseases. In this Review, we describe the existing genome assemblies as well as genetic variation and functional genomic data sets. We highlight some of the challenges with sample acquisition. Finally, we explore how technological advances in single-cell functional genomics and induced pluripotent stem cell-derived organoids will facilitate our understanding of the molecular foundations of primate biology.
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14
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Abstract
Cell fusions have a long history of supporting biomedical research. These experimental models, historically referred to as 'somatic cell hybrids', involve combining the plasma membranes of two cells and merging their nuclei within a single cytoplasm. Cell fusion studies involving human and chimpanzee pluripotent stem cells, rather than somatic cells, highlight the need for responsible communication and a revised nomenclature. Applying the terms 'hybrid' and 'parental' to the fused and source cell lines, respectively, evokes reproductive relationships that do not exist between humans and other species. These misnomers become more salient in the context of fused pluripotent stem cells derived from different but closely related species. Here, we propose a precise, versatile and generalizable framework to describe these fused cell lines. We recommend the term 'composite cell line', to distinguish cell lines that are experimentally created through fusions from both reproductive hybrids and natural cell fusion events without obscuring the model in overly technical terms. For scientific audiences, we further recommend technical nomenclature that describes the contributing species, ploidy and cell type.
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