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Poszewiecka B, Gogolewski K, Karolak JA, Stankiewicz P, Gambin A. PhaseDancer: a novel targeted assembler of segmental duplications unravels the complexity of the human chromosome 2 fusion going from 48 to 46 chromosomes in hominin evolution. Genome Biol 2023; 24:205. [PMID: 37697406 PMCID: PMC10496407 DOI: 10.1186/s13059-023-03022-8] [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: 12/16/2022] [Accepted: 07/25/2023] [Indexed: 09/13/2023] Open
Abstract
Resolving complex genomic regions rich in segmental duplications (SDs) is challenging due to the high error rate of long-read sequencing. Here, we describe a targeted approach with a novel genome assembler PhaseDancer that extends SD-rich regions of interest iteratively. We validate its robustness and efficiency using a golden-standard set of human BAC clones and in silico-generated SDs with predefined evolutionary scenarios. PhaseDancer enables extension of the incomplete complex SD-rich subtelomeric regions of Great Ape chromosomes orthologous to the human chromosome 2 (HSA2) fusion site, informing a model of HSA2 formation and unravelling the evolution of human and Great Ape genomes.
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Affiliation(s)
- Barbara Poszewiecka
- Faculty of Mathematics, Informatics, and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
| | - Krzysztof Gogolewski
- Faculty of Mathematics, Informatics, and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
| | - Justyna A. Karolak
- Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, 77030 Houston, TX USA
- Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, 60-806 Poznan, Poland
| | - Paweł Stankiewicz
- Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, 77030 Houston, TX USA
| | - Anna Gambin
- Faculty of Mathematics, Informatics, and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
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Qian R, Xie F, Zhang W, Kong J, Zhou X, Wang C, Li X. Genome-wide detection of CNV regions between Anqing six-end-white and Duroc pigs. Mol Cytogenet 2023; 16:12. [PMID: 37400846 PMCID: PMC10316616 DOI: 10.1186/s13039-023-00646-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/19/2023] [Indexed: 07/05/2023] Open
Abstract
BACKGROUND Anqing six-end-white pig is a native breed in Anhui Province. The pigs have the disadvantages of a slow growth rate, low proportion of lean meat, and thick back fat, but feature the advantages of strong stress resistance and excellent meat quality. Duroc pig is an introduced pig breed with a fast growth rate and high proportion of lean meat. With the latter breed featuring superior growth characteristics but inferior meat quality traits, the underlying molecular mechanism that causes these phenotypic differences between Chinese and foreign pigs is still unclear. RESULTS In this study, copy number variation (CNV) detection was performed using the re-sequencing data of Anqing Six-end-white pigs and Duroc pigs, A total of 65,701 CNVs were obtained. After merging the CNVs with overlapping genomic positions, 881 CNV regions (CNVRs) were obtained. Based on the obtained CNVR information combined with their positions on the 18 chromosomes, a whole-genome map of the pig CNVs was drawn. GO analysis of the genes in the CNVRs showed that they were primarily involved in the cellular processes of proliferation, differentiation, and adhesion, and primarily involved in the biological processes of fat metabolism, reproductive traits, and immune processes. CONCLUSION The difference analysis of the CNVs between the Chinese and foreign pig breeds showed that the CNV of the Anqing six-end-white pig genome was higher than that of the introduced pig breed Duroc. Six genes related to fat metabolism, reproductive performance, and stress resistance were found in genome-wide CNVRs (DPF3, LEPR, MAP2K6, PPARA, TRAF6, NLRP4).
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Affiliation(s)
- Rong Qian
- Institue of Agricultural Economics and Information, Anhui Academy of Agricultural Sciences, Hefei, 230031, Anhui, China
| | - Fei Xie
- College of Animal Science, Anhui Science and Technology University, Fengyang County, 233100, Anhui Province, China
| | - Wei Zhang
- Institue of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, Anhui, China
| | - JuanJuan Kong
- Institue of Agricultural Economics and Information, Anhui Academy of Agricultural Sciences, Hefei, 230031, Anhui, China
| | - Xueli Zhou
- Institue of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, Anhui, China
| | - Chonglong Wang
- Institue of Animal Husbandry and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei, 230031, Anhui, China.
| | - Xiaojin Li
- College of Animal Science, Anhui Science and Technology University, Fengyang County, 233100, Anhui Province, China.
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Delihas N. Formation of a Family of Long Intergenic Noncoding RNA Genes with an Embedded Translocation Breakpoint Motif in Human Chromosomal Low Copy Repeats of 22q11.2-Some Surprises and Questions. Noncoding RNA 2018; 4:ncrna4030016. [PMID: 30036931 PMCID: PMC6162681 DOI: 10.3390/ncrna4030016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 07/14/2018] [Accepted: 07/17/2018] [Indexed: 12/22/2022] Open
Abstract
A family of long intergenic noncoding RNA (lincRNA) genes, FAM230 is formed via gene sequence duplication, specifically in human chromosomal low copy repeats (LCR) or segmental duplications. This is the first group of lincRNA genes known to be formed by segmental duplications and is consistent with current views of evolution and the creation of new genes via DNA low copy repeats. It appears to be an efficient way to form multiple lincRNA genes. But as these genes are in a critical chromosomal region with respect to the incidence of abnormal translocations and resulting genetic abnormalities, the 22q11.2 region, and also carry a translocation breakpoint motif, several intriguing questions arise concerning the presence and function of the translocation breakpoint sequence in RNA genes situated in LCR22s.
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Affiliation(s)
- Nicholas Delihas
- Department of Molecular Genetics and Microbiology, School of Medicine, Stony Brook University, Stony Brook, New York, NY 11794-5222, USA.
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4
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Gross JB, Weagley J, Stahl BA, Ma L, Espinasa L, McGaugh SE. A local duplication of the Melanocortin receptor 1 locus in Astyanax. Genome 2017; 61:254-265. [PMID: 28738163 DOI: 10.1139/gen-2017-0049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In this study, we report evidence of a novel duplication of Melanocortin receptor 1 (Mc1r) in the cavefish genome. This locus was discovered following the observation of excessive allelic diversity in a ∼820 bp fragment of Mc1r amplified via degenerate PCR from a natural population of Astyanax aeneus fish from Guerrero, Mexico. The cavefish genome reveals the presence of two closely related Mc1r open reading frames separated by a 1.46 kb intergenic region. One open reading frame corresponds to the previously reported Mc1r receptor, and the other open reading frame (duplicate copy) is 975 bp in length, encoding a receptor of 325 amino acids. Sequence similarity analyses position both copies in the syntenic region of the single Mc1r locus in 16 representative craniate genomes spanning bony fish (including Astyanax) to mammals, suggesting we discovered tandem duplicates of this important gene. The two Mc1r copies share ∼89% sequence similarity and, within Astyanax, are more similar to one another compared to other melanocortin family members. Future studies will inform the precise functional significance of the duplicated Mc1r locus and if this novel copy number variant may have adaptive significance for the Astyanax lineage.
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Affiliation(s)
- Joshua B Gross
- a Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - James Weagley
- b Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108, USA
| | - Bethany A Stahl
- a Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Li Ma
- a Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Luis Espinasa
- c School of Science, Marist College, Poughkeepsie, NY 12601, USA
| | - Suzanne E McGaugh
- b Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108, USA
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Abstract
Human genetic studies have been the driving force in bringing to light the underlying biology of psychiatric conditions. As these studies fill in the gaps in our knowledge of the mechanisms at play, we will be better equipped to design therapies in rational and targeted ways, or repurpose existing therapies in previously unanticipated ways. This review is intended for those unfamiliar with psychiatric genetics as a field and provides a primer on different modes of genetic variation, the technologies currently used to probe them, and concepts that provide context for interpreting the gene-phenotype relationship. Like other subfields in human genetics, psychiatric genetics is moving from microarray technology to sequencing-based approaches as barriers of cost and expertise are removed, and the ramifications of this transition are discussed here. A summary is then given of recent genetic discoveries in a number of neuropsychiatric conditions, with particular emphasis on neurodevelopmental conditions. The general impact of genetics on drug development has been to underscore the extensive etiological heterogeneity in seemingly cohesive diagnostic categories. Consequently, the path forward is not in therapies hoping to reach large swaths of patients sharing a clinically defined diagnosis, but rather in targeting patients belonging to specific "biotypes" defined through a combination of objective, quantifiable data, including genotype.
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Affiliation(s)
- Jacob J Michaelson
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA.
- Department of Biomedical Engineering, University of Iowa College of Engineering, Iowa City, IA, USA.
- Department of Communication Sciences and Disorders, University of Iowa College of Liberal Arts and Sciences, Iowa City, IA, USA.
- Iowa Institute of Human Genetics, University of Iowa, Iowa City, IA, USA.
- Genetics Cluster Initiative, University of Iowa, Iowa City, IA, USA.
- The DeLTA Center, University of Iowa, Iowa City, IA, USA.
- University of Iowa Informatics Initiative, University of Iowa, Iowa City, IA, USA.
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Dougherty ML, Nuttle X, Penn O, Nelson BJ, Huddleston J, Baker C, Harshman L, Duyzend MH, Ventura M, Antonacci F, Sandstrom R, Dennis MY, Eichler EE. The birth of a human-specific neural gene by incomplete duplication and gene fusion. Genome Biol 2017; 18:49. [PMID: 28279197 PMCID: PMC5345166 DOI: 10.1186/s13059-017-1163-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/27/2017] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Gene innovation by duplication is a fundamental evolutionary process but is difficult to study in humans due to the large size, high sequence identity, and mosaic nature of segmental duplication blocks. The human-specific gene hydrocephalus-inducing 2, HYDIN2, was generated by a 364 kbp duplication of 79 internal exons of the large ciliary gene HYDIN from chromosome 16q22.2 to chromosome 1q21.1. Because the HYDIN2 locus lacks the ancestral promoter and seven terminal exons of the progenitor gene, we sought to characterize transcription at this locus by coupling reverse transcription polymerase chain reaction and long-read sequencing. RESULTS 5' RACE indicates a transcription start site for HYDIN2 outside of the duplication and we observe fusion transcripts spanning both the 5' and 3' breakpoints. We observe extensive splicing diversity leading to the formation of altered open reading frames (ORFs) that appear to be under relaxed selection. We show that HYDIN2 adopted a new promoter that drives an altered pattern of expression, with highest levels in neural tissues. We estimate that the HYDIN duplication occurred ~3.2 million years ago and find that it is nearly fixed (99.9%) for diploid copy number in contemporary humans. Examination of 73 chromosome 1q21 rearrangement patients reveals that HYDIN2 is deleted or duplicated in most cases. CONCLUSIONS Together, these data support a model of rapid gene innovation by fusion of incomplete segmental duplications, altered tissue expression, and potential subfunctionalization or neofunctionalization of HYDIN2 early in the evolution of the Homo lineage.
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Affiliation(s)
- Max L Dougherty
- Department of Genome Sciences, University of Washington School of Medicine, 3720 15 Ave NE, S413C, Box 355065, Seattle, WA, 98195-5065, USA
| | - Xander Nuttle
- Department of Genome Sciences, University of Washington School of Medicine, 3720 15 Ave NE, S413C, Box 355065, Seattle, WA, 98195-5065, USA
| | - Osnat Penn
- Department of Genome Sciences, University of Washington School of Medicine, 3720 15 Ave NE, S413C, Box 355065, Seattle, WA, 98195-5065, USA
| | - Bradley J Nelson
- Department of Genome Sciences, University of Washington School of Medicine, 3720 15 Ave NE, S413C, Box 355065, Seattle, WA, 98195-5065, USA
| | - John Huddleston
- Department of Genome Sciences, University of Washington School of Medicine, 3720 15 Ave NE, S413C, Box 355065, Seattle, WA, 98195-5065, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98195, USA
| | - Carl Baker
- Department of Genome Sciences, University of Washington School of Medicine, 3720 15 Ave NE, S413C, Box 355065, Seattle, WA, 98195-5065, USA
| | - Lana Harshman
- Department of Genome Sciences, University of Washington School of Medicine, 3720 15 Ave NE, S413C, Box 355065, Seattle, WA, 98195-5065, USA
| | - Michael H Duyzend
- Department of Genome Sciences, University of Washington School of Medicine, 3720 15 Ave NE, S413C, Box 355065, Seattle, WA, 98195-5065, USA
| | - Mario Ventura
- Department of Biology, University of Bari, Bari, 70121, Italy
| | | | | | - Megan Y Dennis
- Department of Genome Sciences, University of Washington School of Medicine, 3720 15 Ave NE, S413C, Box 355065, Seattle, WA, 98195-5065, USA
- Genome Center, MIND Institute, and Department of Biochemistry & Molecular Medicine, University of California, Davis, 95616, CA, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, 3720 15 Ave NE, S413C, Box 355065, Seattle, WA, 98195-5065, USA.
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98195, USA.
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Schmidt K, Noureen A, Kronenberg F, Utermann G. Structure, function, and genetics of lipoprotein (a). J Lipid Res 2016; 57:1339-59. [PMID: 27074913 DOI: 10.1194/jlr.r067314] [Citation(s) in RCA: 302] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Indexed: 12/29/2022] Open
Abstract
Lipoprotein (a) [Lp(a)] has attracted the interest of researchers and physicians due to its intriguing properties, including an intragenic multiallelic copy number variation in the LPA gene and the strong association with coronary heart disease (CHD). This review summarizes present knowledge of the structure, function, and genetics of Lp(a) with emphasis on the molecular and population genetics of the Lp(a)/LPA trait, as well as aspects of genetic epidemiology. It highlights the role of genetics in establishing Lp(a) as a risk factor for CHD, but also discusses uncertainties, controversies, and lack of knowledge on several aspects of the genetic Lp(a) trait, not least its function.
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Affiliation(s)
- Konrad Schmidt
- Divisions of Human Genetics Medical University of Innsbruck, Innsbruck, Austria Genetic Epidemiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Asma Noureen
- Genetic Epidemiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Florian Kronenberg
- Genetic Epidemiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Gerd Utermann
- Divisions of Human Genetics Medical University of Innsbruck, Innsbruck, Austria
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8
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Yuan B, Liu P, Gupta A, Beck CR, Tejomurtula A, Campbell IM, Gambin T, Simmons AD, Withers MA, Harris RA, Rogers J, Schwartz DC, Lupski JR. Comparative Genomic Analyses of the Human NPHP1 Locus Reveal Complex Genomic Architecture and Its Regional Evolution in Primates. PLoS Genet 2015; 11:e1005686. [PMID: 26641089 PMCID: PMC4671654 DOI: 10.1371/journal.pgen.1005686] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 10/29/2015] [Indexed: 11/30/2022] Open
Abstract
Many loci in the human genome harbor complex genomic structures that can result in susceptibility to genomic rearrangements leading to various genomic disorders. Nephronophthisis 1 (NPHP1, MIM# 256100) is an autosomal recessive disorder that can be caused by defects of NPHP1; the gene maps within the human 2q13 region where low copy repeats (LCRs) are abundant. Loss of function of NPHP1 is responsible for approximately 85% of the NPHP1 cases—about 80% of such individuals carry a large recurrent homozygous NPHP1 deletion that occurs via nonallelic homologous recombination (NAHR) between two flanking directly oriented ~45 kb LCRs. Published data revealed a non-pathogenic inversion polymorphism involving the NPHP1 gene flanked by two inverted ~358 kb LCRs. Using optical mapping and array-comparative genomic hybridization, we identified three potential novel structural variant (SV) haplotypes at the NPHP1 locus that may protect a haploid genome from the NPHP1 deletion. Inter-species comparative genomic analyses among primate genomes revealed massive genomic changes during evolution. The aggregated data suggest that dynamic genomic rearrangements occurred historically within the NPHP1 locus and generated SV haplotypes observed in the human population today, which may confer differential susceptibility to genomic instability and the NPHP1 deletion within a personal genome. Our study documents diverse SV haplotypes at a complex LCR-laden human genomic region. Comparative analyses provide a model for how this complex region arose during primate evolution, and studies among humans suggest that intra-species polymorphism may potentially modulate an individual’s susceptibility to acquiring disease-associated alleles. Genomic instability due to the intrinsic sequence architecture of the genome, such as low copy repeats (LCRs), is a major contributor to de novo mutations that can occur in the process of human genome evolution. LCRs can mediate genomic rearrangements associated with genomic disorders by acting as substrates for nonallelic homologous recombination. Juvenile-onset nephronophthisis 1 is the most frequent genetic cause of renal failure in children. An LCR-mediated, homozygous common recurrent deletion encompassing NPHP1 is found in the majority of affected subjects, while heterozygous deletion representing the nephronophthisis 1 recessive carrier state is frequently observed amongst world populations. Interestingly, the human NPHP1 locus is located proximal to the head-to-head fusion site of two ancestral chromosomes that occurred in the great apes, which resulted in a reduction of chromosome number from 48 in nonhuman primates to the current 46 in humans. In this study, we characterized and provided evidence for the diverse genomic architecture at the NPHP1 locus and potential structural variant haplotypes in the human population. Furthermore, our analyses of primate genomes shed light on the massive changes of genomic architecture at the human NPHP1 locus and delineated a model for the emergence of the LCRs during primate evolution.
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Affiliation(s)
- Bo Yuan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Aditya Gupta
- Laboratory for Molecular and Computational Genomics, Department of Chemistry, Laboratory of Genetics and The UW-Biotechnology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Christine R. Beck
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Anusha Tejomurtula
- Graduate Program in Diagnostic Genetics, School of Health Professions, University of Texas MD Anderson Cancer Center, Houston, Texas, United States of America
| | - Ian M. Campbell
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Tomasz Gambin
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alexandra D. Simmons
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Marjorie A. Withers
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - R. Alan Harris
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - Jeffrey Rogers
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - David C. Schwartz
- Laboratory for Molecular and Computational Genomics, Department of Chemistry, Laboratory of Genetics and The UW-Biotechnology Center, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children’s Hospital, Houston, Texas, United States of America
- * E-mail:
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Kim YJ, Ahn K, Gim JA, Oh MH, Han K, Kim HS. Gene structure variation in segmental duplication block C of human chromosome 7q 11.23 during primate evolution. Gene 2015. [PMID: 26196062 DOI: 10.1016/j.gene.2015.07.060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Segmental duplication, or low-copy repeat (LCR) event, occurs during primate evolution and is an important source of genomic diversity, including gain or loss of gene function. The human chromosome 7q 11.23 is related to the William-Beuren syndrome and contains large region-specific LCRs composed of blocks A, B, and C that have different copy numbers in humans and different primates. We analyzed the structure of POM121, NSUN5, FKBP6, and TRIM50 genes in the LCRs of block C. Based on computational analysis, POM121B created by a segmental duplication acquired a new exonic region, whereas NSUN5B (NSUN5C) showed structural variation by integration of HERV-K LTR after duplication from the original NSUN5 gene. The TRIM50 gene originally consists of seven exons, whereas the duplicated TRIM73 and TRIM74 genes present five exons because of homologous recombination-mediated deletion. In addition, independent duplication events of the FKBP6 gene generated two pseudogenes at different genomic locations. In summary, these clustered genes are created by segmental duplication, indicating that they show dynamic evolutionary events, leading to structure variation in the primate genome.
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Affiliation(s)
- Yun-Ji Kim
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330-714, Republic of Korea; DKU-Theragen Institute for NGS Analysis (DTiNa), Cheonan 330-714, Republic of Korea
| | - Kung Ahn
- TBI, Theragen BiO Institute, TheragenEtex, Suwon 443-270, Republic of Korea
| | - Jeong-An Gim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea
| | - Man Hwan Oh
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330-714, Republic of Korea
| | - Kyudong Han
- Department of Nanobiomedical Science & BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330-714, Republic of Korea; DKU-Theragen Institute for NGS Analysis (DTiNa), Cheonan 330-714, Republic of Korea
| | - Heui-Soo Kim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 609-735, Republic of Korea.
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10
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Yuan B, Harel T, Gu S, Liu P, Burglen L, Chantot-Bastaraud S, Gelowani V, Beck C, Carvalho C, Cheung S, Coe A, Malan V, Munnich A, Magoulas P, Potocki L, Lupski J. Nonrecurrent 17p11.2p12 Rearrangement Events that Result in Two Concomitant Genomic Disorders: The PMP22-RAI1 Contiguous Gene Duplication Syndrome. Am J Hum Genet 2015; 97:691-707. [PMID: 26544804 DOI: 10.1016/j.ajhg.2015.10.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/05/2015] [Indexed: 12/31/2022] Open
Abstract
The genomic duplication associated with Potocki-Lupski syndrome (PTLS) maps in close proximity to the duplication associated with Charcot-Marie-Tooth disease type 1A (CMT1A). PTLS is characterized by hypotonia, failure to thrive, reduced body weight, intellectual disability, and autistic features. CMT1A is a common autosomal dominant distal symmetric peripheral polyneuropathy. The key dosage-sensitive genes RAI1 and PMP22 are respectively associated with PTLS and CMT1A. Recurrent duplications accounting for the majority of subjects with these conditions are mediated by nonallelic homologous recombination between distinct low-copy repeat (LCR) substrates. The LCRs flanking a contiguous genomic interval encompassing both RAI1 and PMP22 do not share extensive homology; thus, duplications encompassing both loci are rare and potentially generated by a different mutational mechanism. We characterized genomic rearrangements that simultaneously duplicate PMP22 and RAI1, including nine potential complex genomic rearrangements, in 23 subjects by high-resolution array comparative genomic hybridization and breakpoint junction sequencing. Insertions and microhomologies were found at the breakpoint junctions, suggesting potential replicative mechanisms for rearrangement formation. At the breakpoint junctions of these nonrecurrent rearrangements, enrichment of repetitive DNA sequences was observed, indicating that they might predispose to genomic instability and rearrangement. Clinical evaluation revealed blended PTLS and CMT1A phenotypes with a potential earlier onset of neuropathy. Moreover, additional clinical findings might be observed due to the extra duplicated material included in the rearrangements. Our genomic analysis suggests replicative mechanisms as a predominant mechanism underlying PMP22-RAI1 contiguous gene duplications and provides further evidence supporting the role of complex genomic architecture in genomic instability.
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11
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Ruchi R, Genovese G, Lee J, Charoonratana VT, Bernhardy AJ, Alper SL, Kopp JB, Thadhani R, Friedman DJ, Pollak MR. Copy Number Variation at the APOL1 Locus. PLoS One 2015; 10:e0125410. [PMID: 25933006 PMCID: PMC4416782 DOI: 10.1371/journal.pone.0125410] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 03/23/2015] [Indexed: 11/26/2022] Open
Abstract
Two coding variants in the APOL1 gene (G1 and G2) explain most of the high rate of kidney disease in African Americans. APOL1-associated kidney disease risk inheritance follows an autosomal recessive pattern: The relative risk of kidney disease associated with inheritance of two high-risk variants is 7–30 fold, depending on the specific kidney phenotype. We wished to determine if the variability in phenotype might in part reflect structural differences in APOL1 gene. We analyzed sequence coverage from 1000 Genomes Project Phase 3 samples as well as exome sequencing data from African American kidney disease cases for copy number variation. 8 samples sequenced in the 1000 Genomes Project showed increased coverage over a ~100kb region that includes APOL2, APOL1 and part of MYH9, suggesting the presence of APOL1 copy number greater than 2. We reasoned that such duplications should be enriched in apparent G1 heterozygotes with kidney disease. Using a PCR-based assay, we observed the presence of this duplication in additional samples from apparent G0G1 or G0G2 individuals. The frequency of this APOL1 duplication was compared among cases (n = 123) and controls (n = 255) with apparent G0G1 heterozygosity. The presence of APOL1 duplication was observed in 4.06% of cases and 0.78% controls, preliminary evidence that this APOL1 duplication may alter susceptibility to kidney disease (p = 0.03). Taqman-based copy number assays confirmed the presence of 3 APOL1 copies in individuals positive for this specific duplication by PCR assay, but also identified a small number of individuals with additional APOL1 copies of presumably different structure. These observations motivate further studies to better assess the contribution of APOL1 copy number on kidney disease risk and on APOL1 function. Investigators and clinicians genotyping APOL1 should also consider whether the particular genotyping platform used is subject to technical errors when more than two copies of APOL1 are present.
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Affiliation(s)
- Rupam Ruchi
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- Division of Nephrology, Department of Medicine, University of Florida, Gainesville, Florida, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Giulio Genovese
- Stanley Center, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Jessica Lee
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Victoria T. Charoonratana
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Andrea J. Bernhardy
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Seth L. Alper
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- Stanley Center, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Jeffrey B. Kopp
- Kidney Diseases Branch, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ravi Thadhani
- Renal Unit, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - David J. Friedman
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Martin R. Pollak
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
- * E-mail:
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12
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Zagaria A, Anelli L, Coccaro N, Tota G, Casieri P, Cellamare A, Minervini A, Minervini CF, Brunetti C, Cumbo C, Specchia G, Albano F. 5'RUNX1-3'USP42 chimeric gene in acute myeloid leukemia can occur through an insertion mechanism rather than translocation and may be mediated by genomic segmental duplications. Mol Cytogenet 2014; 7:66. [PMID: 25298786 PMCID: PMC4189616 DOI: 10.1186/s13039-014-0066-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 09/17/2014] [Indexed: 12/17/2022] Open
Abstract
Background The runt-related transcription factor 1 (RUNX1) gene is a transcription factor that acts as a master regulator of hematopoiesis and represents one of the most frequent targets of chromosomal rearrangements in human leukemias. The t(7;21)(p22;q22) rearrangement generating a 5′RUNX1-3′USP42 fusion transcript has been reported in two cases of pediatric acute myeloid leukemia (AML) and further in eight adult cases of myeloid neoplasms. We describe the first case of adult AML with a 5′RUNX1-3′USP42 fusion gene generated by an insertion event instead of chromosomal translocation. Methods Conventional and molecular cytogenetic analyses allowed the precise characterization of the chromosomal rearrangement and breakpoints identification. Gene expression analysis was performed by quantitative real-time PCR experiments, whereas bioinformatic studies were carried out for revealing structural genomic characteristics of breakpoint regions. Results We identified an adult AML case bearing a ins(21;7)(q22;p15p22) generating a 5′RUNX1-3′USP42 fusion gene on der(21) chromosome and causing USP42 gene over-expression. Bioinformatic analysis of the genomic regions involved in ins(21;7)/t(7;21) showed the presence of interchromosomal segmental duplications (SDs) next to the USP42 and RUNX1 genes, that may underlie a non-allelic homologous recombination between chromosome 7 and 21 in AML. Conclusions We report the first case of a 5′RUNX1-3′USP42 chimeric gene generated by a chromosomal cryptic insertion in an adult AML patient. Our data revealed that there may be a pivotal role for SDs in this very rare but recurrent chromosomal rearrangement.
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Affiliation(s)
- Antonella Zagaria
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Luisa Anelli
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Nicoletta Coccaro
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Giuseppina Tota
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Paola Casieri
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Angelo Cellamare
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Angela Minervini
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Crescenzio Francesco Minervini
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Claudia Brunetti
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Cosimo Cumbo
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Giorgina Specchia
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
| | - Francesco Albano
- Department of Emergency and Organ Transplantation (D.E.T.O.), Hematology Section - University of Bari, P.zza G. Cesare, 11 70124 Bari, Italy
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13
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Dios F, Barturen G, Lebrón R, Rueda A, Hackenberg M, Oliver JL. DNA clustering and genome complexity. Comput Biol Chem 2014; 53 Pt A:71-8. [PMID: 25182383 DOI: 10.1016/j.compbiolchem.2014.08.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2014] [Indexed: 01/08/2023]
Abstract
Early global measures of genome complexity (power spectra, the analysis of fluctuations in DNA walks or compositional segmentation) uncovered a high degree of complexity in eukaryotic genome sequences. The main evolutionary mechanisms leading to increases in genome complexity (i.e. gene duplication and transposon proliferation) can all potentially produce increases in DNA clustering. To quantify such clustering and provide a genome-wide description of the formed clusters, we developed GenomeCluster, an algorithm able to detect clusters of whatever genome element identified by chromosome coordinates. We obtained a detailed description of clusters for ten categories of human genome elements, including functional (genes, exons, introns), regulatory (CpG islands, TFBSs, enhancers), variant (SNPs) and repeat (Alus, LINE1) elements, as well as DNase hypersensitivity sites. For each category, we located their clusters in the human genome, then quantifying cluster length and composition, and estimated the clustering level as the proportion of clustered genome elements. In average, we found a 27% of elements in clusters, although a considerable variation occurs among different categories. Genes form the lowest number of clusters, but these are the longest ones, both in bp and the average number of components, while the shortest clusters are formed by SNPs. Functional and regulatory elements (genes, CpG islands, TFBSs, enhancers) show the highest clustering level, as compared to DNase sites, repeats (Alus, LINE1) or SNPs. Many of the genome elements we analyzed are known to be composed of clusters of low-level entities. In addition, we found here that the clusters generated by GenomeCluster can be in turn clustered into high-level super-clusters. The observation of 'clusters-within-clusters' parallels the 'domains within domains' phenomenon previously detected through global statistical methods in eukaryotic sequences, and reveals a complex human genome landscape dominated by hierarchical clustering.
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Affiliation(s)
- Francisco Dios
- Dpto. de Genética, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain; Lab. de Bioinformática, Inst. de Biotecnología, Centro de Investigación Biomédica, 18100 Granada, Spain
| | - Guillermo Barturen
- Dpto. de Genética, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain; Lab. de Bioinformática, Inst. de Biotecnología, Centro de Investigación Biomédica, 18100 Granada, Spain
| | - Ricardo Lebrón
- Dpto. de Genética, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain; Lab. de Bioinformática, Inst. de Biotecnología, Centro de Investigación Biomédica, 18100 Granada, Spain
| | - Antonio Rueda
- Plataforma Andaluza de Genómica y Bioinformática (GBPA), Edificio INSUR, Calle Albert Einstein, 41092 Sevilla, Spain
| | - Michael Hackenberg
- Dpto. de Genética, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain; Lab. de Bioinformática, Inst. de Biotecnología, Centro de Investigación Biomédica, 18100 Granada, Spain
| | - José L Oliver
- Dpto. de Genética, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain; Lab. de Bioinformática, Inst. de Biotecnología, Centro de Investigación Biomédica, 18100 Granada, Spain.
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Li W, Freudenberg J. Characterizing regions in the human genome unmappable by next-generation-sequencing at the read length of 1000 bases. Comput Biol Chem 2014; 53 Pt A:108-17. [PMID: 25241312 DOI: 10.1016/j.compbiolchem.2014.08.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2014] [Indexed: 12/31/2022]
Abstract
Repetitive and redundant regions of a genome are particularly problematic for mapping sequencing reads. In the present paper, we compile a list of the unmappable regions in the human genome based on the following definition: hypothetical reads with length 1 kb which cannot be uniquely mapped with zero-mismatch alignment for the described regions, considering both the forward and reverse strand. The respective collection of unmappable regions covers 0.77% of the sequence of human autosomes and 8.25% of the sex chromosomes in the reference genome GRCh37/hg19 (overall 1.23%). Not surprisingly, our unmappable regions overlap greatly with segmental duplication, transposable elements, and structural variants. About 99.8% of bases in our unmappable regions are part of either segmental duplication or transposable elements and 98.3% overlap structural variant annotations. Notably, some of these regions overlap units with important biological functions, including 4% of protein-coding genes. In contrast, these regions have zero intersection with the ultraconserved elements, very low overlap with microRNAs, tRNAs, pseudogenes, CpG islands, tandem repeats, microsatellites, sensitive non-coding regions, and the mapping blacklist regions from the ENCODE project.
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Affiliation(s)
- Wentian Li
- The Robert S. Boas Center for Genomics and Human Genetics, The Feinstein Institute for Medical Research, North Shore LIJ Health System, 350 Community Drive, Manhasset, NY 11030, USA.
| | - Jan Freudenberg
- The Robert S. Boas Center for Genomics and Human Genetics, The Feinstein Institute for Medical Research, North Shore LIJ Health System, 350 Community Drive, Manhasset, NY 11030, USA
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15
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Ebert G, Steininger A, Weißmann R, Boldt V, Lind-Thomsen A, Grune J, Badelt S, Heßler M, Peiser M, Hitzler M, Jensen LR, Müller I, Hu H, Arndt PF, Kuss AW, Tebel K, Ullmann R. Distribution of segmental duplications in the context of higher order chromatin organisation of human chromosome 7. BMC Genomics 2014; 15:537. [PMID: 24973960 PMCID: PMC4092221 DOI: 10.1186/1471-2164-15-537] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 06/17/2014] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Segmental duplications (SDs) are not evenly distributed along chromosomes. The reasons for this biased susceptibility to SD insertion are poorly understood. Accumulation of SDs is associated with increased genomic instability, which can lead to structural variants and genomic disorders such as the Williams-Beuren syndrome. Despite these adverse effects, SDs have become fixed in the human genome. Focusing on chromosome 7, which is particularly rich in interstitial SDs, we have investigated the distribution of SDs in the context of evolution and the three dimensional organisation of the chromosome in order to gain insights into the mutual relationship of SDs and chromatin topology. RESULTS Intrachromosomal SDs preferentially accumulate in those segments of chromosome 7 that are homologous to marmoset chromosome 2. Although this formerly compact segment has been re-distributed to three different sites during primate evolution, we can show by means of public data on long distance chromatin interactions that these three intervals, and consequently the paralogous SDs mapping to them, have retained their spatial proximity in the nucleus. Focusing on SD clusters implicated in the aetiology of the Williams-Beuren syndrome locus we demonstrate by cross-species comparison that these SDs have inserted at the borders of a topological domain and that they flank regions with distinct DNA conformation. CONCLUSIONS Our study suggests a link of nuclear architecture and the propagation of SDs across chromosome 7, either by promoting regional SD insertion or by contributing to the establishment of higher order chromatin organisation themselves. The latter could compensate for the high risk of structural rearrangements and thus may have contributed to their evolutionary fixation in the human genome.
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Affiliation(s)
- Grit Ebert
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
- />Department of Biology, Chemistry and Pharmacy, Free University Berlin, 14195 Berlin, Germany
| | - Anne Steininger
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
- />Department of Biology, Chemistry and Pharmacy, Free University Berlin, 14195 Berlin, Germany
| | - Robert Weißmann
- />Department of Human Genetics, University Medicine Greifswald, and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, Fleischmannstraße 42-44, 17475 Greifswald, Germany
| | - Vivien Boldt
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
- />Department of Biology, Chemistry and Pharmacy, Free University Berlin, 14195 Berlin, Germany
| | - Allan Lind-Thomsen
- />Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Jana Grune
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
| | - Stefan Badelt
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
- />Institute for Theoretical Chemistry, University of Vienna, Waehringer Straße 17, A-1090 Vienna, Austria
| | - Melanie Heßler
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
| | - Matthias Peiser
- />Unit Experimental Research, Department of Product Safety, Federal Institute for Bundeswehr Institute of Radiobiology affiliated, the University of Ulm, Neuherbergstraße 11, 80937 Munich, Germany
| | - Manuel Hitzler
- />Unit Experimental Research, Department of Product Safety, Federal Institute for Bundeswehr Institute of Radiobiology affiliated, the University of Ulm, Neuherbergstraße 11, 80937 Munich, Germany
| | - Lars R Jensen
- />Department of Human Genetics, University Medicine Greifswald, and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, Fleischmannstraße 42-44, 17475 Greifswald, Germany
| | - Ines Müller
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
| | - Hao Hu
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
| | - Peter F Arndt
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
| | - Andreas W Kuss
- />Department of Human Genetics, University Medicine Greifswald, and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, Fleischmannstraße 42-44, 17475 Greifswald, Germany
| | - Katrin Tebel
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
| | - Reinhard Ullmann
- />Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, 14195 Berlin, Germany
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Le Tanno P, Poreau B, Devillard F, Vieville G, Amblard F, Jouk PS, Satre V, Coutton C. Maternal complex chromosomal rearrangement leads to TCF12 microdeletion in a patient presenting with coronal craniosynostosis and intellectual disability. Am J Med Genet A 2014; 164A:1530-6. [PMID: 24648389 DOI: 10.1002/ajmg.a.36467] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 12/29/2013] [Indexed: 01/21/2023]
Abstract
We report on a young child with intellectual disability and unilateral coronal craniosynostosis leading to craniofacial malformations. Standard karyotype showed an apparently balanced translocation between chromosomes 2 and 15 [t(2;15)(q21;q21.3)], inherited from his mother. Interestingly, array-CGH 180K showed a 3.64 Mb de novo deletion on chromosome 15 in the region 15q21.3q22.2, close to the chromosome 15 translocation breakpoints. This deletion leads to haploinsufficiency of TCF12 gene that can explain the coronal craniosynostosis described in the patient. Additional FISH analyses showed a complex balanced maternal chromosomal rearrangement combining the reciprocal translocation t(2;15)(q21;q21.3), and an insertion of the 15q22.1 segment into the telomeric region of the translocated 15q fragment. The genomic imbalance in the patient is likely caused by a crossing-over that occurs in the recombination loop formed during the maternal meiosis resulting in the deletion of the inserted fragment. This original case of a genomic microdeletion of TCF12 exemplifies the importance of array-CGH in the clinical investigation of apparently balanced rearrangements but also the importance of FISH analysis to identify the chromosomal mechanism causing the genomic imbalance.
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Affiliation(s)
- Pauline Le Tanno
- Laboratoire de Génétique Chromosomique, Département de Génétique et Procréation, Hôpital Couple Enfant, CHU Grenoble, Grenoble, France
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17
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Jovelin R, Cutter AD. Fine-scale signatures of molecular evolution reconcile models of indel-associated mutation. Genome Biol Evol 2013; 5:978-86. [PMID: 23558593 PMCID: PMC3673634 DOI: 10.1093/gbe/evt051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Genomic structural alterations that vary within species, known as large copy number variants, represent an unanticipated and abundant source of genetic diversity that associates with variation in gene expression and susceptibility to disease. Even short insertions and deletions (indels) can exert important effects on genomes by locally increasing the mutation rate, with multiple mechanisms proposed to account for this pattern. To better understand how indels promote genome evolution, we demonstrate that the single nucleotide mutation rate is elevated in the vicinity of indels, with a resolution of tens of base pairs, for the two closely related nematode species Caenorhabditis remanei and C. sp. 23. In addition to indels being clustered with single nucleotide polymorphisms and fixed differences, we also show that transversion mutations are enriched in sequences that flank indels and that many indels associate with sequence repeats. These observations are compatible with a model that reconciles previously proposed mechanisms of indel-associated mutagenesis, implicating repeat sequences as a common driver of indel errors, which then recruit error-prone polymerases during DNA repair, resulting in a locally elevated single nucleotide mutation rate. The striking influence of indel variants on the molecular evolution of flanking sequences strengthens the emerging general view that mutations can induce further mutations.
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Affiliation(s)
- Richard Jovelin
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada.
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18
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Association of the BRCA1 promoter polymorphism rs11655505 with the risk of familial breast and/or ovarian cancer. Fam Cancer 2013; 12:691-8. [PMID: 23657760 DOI: 10.1007/s10689-013-9647-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Germline mutations in the BRCA1 tumor suppressor gene predispose affected individuals to breast cancer; however, incomplete cancer penetrance and the presence of phenocopies in BRCA1 families also indicate genetic and environmental modifiers of breast cancer risk. In this study, we have tested the single nucleotide polymorphism rs1655505 of the BRCA1 promoter, as candidate for the modifier of breast cancer risk. The polymorphic variants were genotyped in BRCA1-negative (729), familial breast and/or ovarian cancer cases (FBOC), including cases with a reported maternal history (154), nonfamilal (sporadic) cases (600), hereditary breast/ovarian cases with BRCA1 mutations (190) and population controls (1,590) from Central Poland. An association with the risk of FBOC was observed for the minor (T) allele and (TT) genotype (T: p = 0.006, OR = 1.40, 95% CI = 1.10-1.79; TT: p = 0.001, OR = 2.23, 95% CI = 1.37-3.62) in female cases with a reported maternal history, specifically in women with the onset of disease after 50 years of age (T: p = 0.004, OR = 1.77, 95% CI = 1.20-2.62; TT: p = 0.001, OR = 3.7, 95% CI = 1.62-8.46). The presented evidence suggests a need to conduct larger studies on the association between genetic variations at the BRCA1 promoter and the breast cancer risk, according to maternal/paternal lineage.
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19
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Research proceedings on primate comparative genomics. Zool Res 2013; 33:108-18. [DOI: 10.3724/sp.j.1141.2012.01108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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20
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Li J, Harris RA, Cheung SW, Coarfa C, Jeong M, Goodell MA, White LD, Patel A, Kang SH, Shaw C, Chinault AC, Gambin T, Gambin A, Lupski JR, Milosavljevic A. Genomic hypomethylation in the human germline associates with selective structural mutability in the human genome. PLoS Genet 2012; 8:e1002692. [PMID: 22615578 PMCID: PMC3355074 DOI: 10.1371/journal.pgen.1002692] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 03/21/2012] [Indexed: 12/27/2022] Open
Abstract
The hotspots of structural polymorphisms and structural mutability in the human genome remain to be explained mechanistically. We examine associations of structural mutability with germline DNA methylation and with non-allelic homologous recombination (NAHR) mediated by low-copy repeats (LCRs). Combined evidence from four human sperm methylome maps, human genome evolution, structural polymorphisms in the human population, and previous genomic and disease studies consistently points to a strong association of germline hypomethylation and genomic instability. Specifically, methylation deserts, the ∼1% fraction of the human genome with the lowest methylation in the germline, show a tenfold enrichment for structural rearrangements that occurred in the human genome since the branching of chimpanzee and are highly enriched for fast-evolving loci that regulate tissue-specific gene expression. Analysis of copy number variants (CNVs) from 400 human samples identified using a custom-designed array comparative genomic hybridization (aCGH) chip, combined with publicly available structural variation data, indicates that association of structural mutability with germline hypomethylation is comparable in magnitude to the association of structural mutability with LCR–mediated NAHR. Moreover, rare CNVs occurring in the genomes of individuals diagnosed with schizophrenia, bipolar disorder, and developmental delay and de novo CNVs occurring in those diagnosed with autism are significantly more concentrated within hypomethylated regions. These findings suggest a new connection between the epigenome, selective mutability, evolution, and human disease. The human genome contains many loci with high incidence of structural mutations, including insertions and deletions of chromosomal segments. This excessive mutability has accelerated evolution and contributed to human disease but has yet to be explained. Segments of DNA repeated in low-copy numbers (LCRs) have been previously implicated in promoting structural mutability in specific disease-associated loci. Lack of methylation (hypomethylation) of genomic DNA has been previously associated with high structural mutability in gibbons and in human cancer cells, but the association with structural mutability in the human germline has not been explored prior to this study. Our analyses confirm the role of LCRs in promoting structural mutability on the genome scale but also reveal a surprisingly strong association of genomic instability with hypomethylation. Specifically, evolutionary analyses reveal that methylation deserts, the ∼1% fraction of the human genome with the lowest methylation in human sperm, harbor a tenfold higher number of structural mutations than genome-wide average. Moreover, the structural mutations in individuals diagnosed with schizophrenia, bipolar disorder, developmental delay, and autism are significantly more concentrated within hypomethylated regions. Our findings suggest a new connection between methylation of genomic DNA, selective structural mutability, evolution, and human disease.
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Affiliation(s)
- Jian Li
- Bioinformatics Research Laboratory, Epigenome Center, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - R. Alan Harris
- Bioinformatics Research Laboratory, Epigenome Center, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Sau Wai Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Cristian Coarfa
- Bioinformatics Research Laboratory, Epigenome Center, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Mira Jeong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Margaret A. Goodell
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Lisa D. White
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ankita Patel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Sung-Hae Kang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Chad Shaw
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - A. Craig Chinault
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Tomasz Gambin
- Institute of Computer Science, Warsaw University of Technology, Warsaw, Poland
| | - Anna Gambin
- Institute of Informatics, Warsaw University, Warsaw, Poland
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children's Hospital, Houston, Texas, United States of America
| | - Aleksandar Milosavljevic
- Bioinformatics Research Laboratory, Epigenome Center, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Simmons AD, Carvalho CMB, Lupski JR. What have studies of genomic disorders taught us about our genome? Methods Mol Biol 2012; 838:1-27. [PMID: 22228005 DOI: 10.1007/978-1-61779-507-7_1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The elucidation of genomic disorders began with molecular technologies that enabled detection of genomic changes which were (a) smaller than those resolved by traditional cytogenetics (less than 5 Mb) and (b) larger than what could be determined by conventional gel electrophoresis. Methods such as pulsed field gel electrophoresis (PFGE) and fluorescent in situ hybridization (FISH) could resolve such changes but were limited to locus-specific studies. The study of genomic disorders has rapidly advanced with the development of array-based techniques. These enabled examination of the entire human genome at a higher level of resolution, thus allowing elucidation of the basis of many new disorders, mechanisms that result in genomic changes that can result in copy number variation (CNV), and most importantly, a deeper understanding of the characteristics, features, and plasticity of our genome. In this chapter, we focus on the structural and architectural features of the genome, which can potentially result in genomic instability, delineate how mechanisms, such as NAHR, NHEJ, and FoSTeS/MMBIR lead to disease-causing rearrangements, and briefly describe the relationship between the leading methods presently used in studying genomic disorders. We end with a discussion on our new understanding about our genome including: the contribution of new mutation CNV to disease, the abundance of mosaicism, the extent of subtelomeric rearrangements, the frequency of de novo rearrangements associated with sporadic birth defects, the occurrence of balanced and unbalanced translocations, the increasing discovery of insertional translocations, the exploration of complex rearrangements and exonic CNVs. In the postgenomic era, our understanding of the genome has advanced very rapidly as the level of technical resolution has become higher. This leads to a greater understanding of the effects of rearrangements present both in healthy subjects and individuals with clinically relevant phenotypes.
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Liu P, Lacaria M, Zhang F, Withers M, Hastings P, Lupski J. Frequency of nonallelic homologous recombination is correlated with length of homology: evidence that ectopic synapsis precedes ectopic crossing-over. Am J Hum Genet 2011; 89:580-8. [PMID: 21981782 DOI: 10.1016/j.ajhg.2011.09.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/14/2011] [Accepted: 09/15/2011] [Indexed: 10/16/2022] Open
Abstract
Genomic disorders constitute a class of diseases that are associated with DNA rearrangements resulting from region-specific genome instability, that is, genome architecture incites genome instability. Nonallelic homologous recombination (NAHR) or crossing-over in meiosis between sequences that are not in allelic positions (i.e., paralogous sequences) can result in recurrent deletions or duplications causing genomic disorders. Previous studies of NAHR have focused on description of the phenomenon, but it remains unclear how NAHR occurs during meiosis and what factors determine its frequency. Here we assembled two patient cohorts with reciprocal genomic disorders; deletion associated Smith-Magenis syndrome and duplication associated Potocki-Lupski syndrome. By assessing the full spectrum of rearrangement types from the two cohorts, we find that complex rearrangements (those with more than one breakpoint) are more prevalent in copy-number gains (17.7%) than in copy-number losses (2.3%); an observation that supports a role for replicative mechanisms in complex rearrangement formation. Interestingly, for NAHR-mediated recurrent rearrangements, we show that crossover frequency is positively associated with the flanking low-copy repeat (LCR) length and inversely influenced by the inter-LCR distance. To explain this, we propose that the probability of ectopic chromosome synapsis increases with increased LCR length, and that ectopic synapsis is a necessary precursor to ectopic crossing-over.
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Chen Y, Liu YJ, Pei YF, Yang TL, Deng FY, Liu XG, Li DY, Deng HW. Copy number variations at the Prader-Willi syndrome region on chromosome 15 and associations with obesity in whites. Obesity (Silver Spring) 2011; 19:1229-34. [PMID: 21233802 PMCID: PMC4512297 DOI: 10.1038/oby.2010.323] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Obesity is a serious health problem with strong genetic determination. Copy number variation (CNV) is a common type of genomic variant associated with some complex human diseases. However, it is not clear how CNVs contribute to the etiology of obesity. In this study, we examined 1,000 unrelated US whites to search for CNVs that may predispose to obesity. We focused our analyses on the Prader-Willi syndrome (PWS) critical region (chromosome 15q11-q13), because the PWS region is a hotspot for CNV generation and obesity is one of the major clinical manifestations for chromosome abnormalities at this region. We constructed a map containing 39 CNVs at the PWS critical region with CNV occurrence rates higher than 1%. Among them, three CNVs were significantly associated with body fat mass (P < 0.05), with a higher copy number (CN) associated with an increase of 5.08-9.77 kg in body fat mass. These three CNVs are close to two known PWS genes, NDN (necdin homolog) and C15orf2 (chromosome 15 open reading frame 2), and partially overlap with another obesity gene PWRN1 (Prader-Willi region nonprotein-coding RNA 1). Interestingly, our recently published whole genome association scan study using the same sample by examining single-nucleotide polymorphisms (SNPs) did not find any significant associations at these CNV regions, suggesting the importance of examining both CNVs and SNPs for better understanding of genetic basis of obesity. Further studies are warranted to validate these CNVs and their importance to obesity.
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Affiliation(s)
- Yuan Chen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, The People’s Republic of China
| | - Yong-Jun Liu
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Yu-Fang Pei
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, The People’s Republic of China
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Tie-Lin Yang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, The People’s Republic of China
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Fei-Yan Deng
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Xiao-Gang Liu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, The People’s Republic of China
| | - Ding-You Li
- Department of Pediatrics, Children’s Mercy Hospital, Kansas City, Missouri, USA
| | - Hong-Wen Deng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, The People’s Republic of China
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
- Center of System Biomedical Sciences, Shanghai University of Science and Technology, Shanghai, The People’s Republic of China
- College of Life Sciences and Engineering, Beijing Jiao Tong University, Beijing, The People’s Republic of China
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Manthey GM, Bailis AM. Rad51 inhibits translocation formation by non-conservative homologous recombination in Saccharomyces cerevisiae. PLoS One 2010; 5:e11889. [PMID: 20686691 PMCID: PMC2912366 DOI: 10.1371/journal.pone.0011889] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 07/07/2010] [Indexed: 11/24/2022] Open
Abstract
Chromosomal translocations are a primary biological response to ionizing radiation (IR) exposure, and are likely to result from the inappropriate repair of the DNA double-strand breaks (DSBs) that are created. An abundance of repetitive sequences in eukaryotic genomes provides ample opportunity for such breaks to be repaired by homologous recombination (HR) between non-allelic repeats. Interestingly, in the budding yeast, Saccharomyces cerevisiae the central strand exchange protein, Rad51 that is required for DSB repair by gene conversion between unlinked repeats that conserves genomic structure also suppresses translocation formation by several HR mechanisms. In particular, Rad51 suppresses translocation formation by single-strand annealing (SSA), perhaps the most efficient mechanism for translocation formation by HR in both yeast and mammalian cells. Further, the enhanced translocation formation that emerges in the absence of Rad51 displays a distinct pattern of genetic control, suggesting that this occurs by a separate mechanism. Since hypomorphic mutations in RAD51 in mammalian cells also reduce DSB repair by conservative gene conversion and stimulate non-conservative repair by SSA, this mechanism may also operate in humans and, perhaps contribute to the genome instability that propels the development of cancer.
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Affiliation(s)
- Glenn M. Manthey
- Department of Molecular and Cellular Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, United States of America
| | - Adam M. Bailis
- Department of Molecular and Cellular Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, United States of America
- * E-mail:
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Zhang F, Seeman P, Liu P, Weterman MA, Gonzaga-Jauregui C, Towne CF, Batish SD, De Vriendt E, De Jonghe P, Rautenstrauss B, Krause KH, Khajavi M, Posadka J, Vandenberghe A, Palau F, Van Maldergem L, Baas F, Timmerman V, Lupski JR. Mechanisms for nonrecurrent genomic rearrangements associated with CMT1A or HNPP: rare CNVs as a cause for missing heritability. Am J Hum Genet 2010; 86:892-903. [PMID: 20493460 DOI: 10.1016/j.ajhg.2010.05.001] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Revised: 04/28/2010] [Accepted: 05/03/2010] [Indexed: 12/20/2022] Open
Abstract
Genomic rearrangements involving the peripheral myelin protein gene (PMP22) in human chromosome 17p12 are associated with neuropathy: duplications cause Charcot-Marie-Tooth disease type 1A (CMT1A), whereas deletions lead to hereditary neuropathy with liability to pressure palsies (HNPP). Our previous studies showed that >99% of these rearrangements are recurrent and mediated by nonallelic homologous recombination (NAHR). Rare copy number variations (CNVs) generated by nonrecurrent rearrangements also exist in 17p12, but their underlying mechanisms are not well understood. We investigated 21 subjects with rare CNVs associated with CMT1A or HNPP by oligonucleotide-based comparative genomic hybridization microarrays and breakpoint sequence analyses, and we identified 17 unique CNVs, including two genomic deletions, ten genomic duplications, two complex rearrangements, and three small exonic deletions. Each of these CNVs includes either the entire PMP22 gene, or exon(s) only, or ultraconserved potential regulatory sequences upstream of PMP22, further supporting the contention that PMP22 is the critical gene mediating the neuropathy phenotypes associated with 17p12 rearrangements. Breakpoint sequence analysis reveals that, different from the predominant NAHR mechanism in recurrent rearrangement, various molecular mechanisms, including nonhomologous end joining, Alu-Alu-mediated recombination, and replication-based mechanisms (e.g., FoSTeS and/or MMBIR), can generate nonrecurrent 17p12 rearrangements associated with neuropathy. We document a multitude of ways in which gene function can be altered by CNVs. Given the characteristics, including small size, structural complexity, and location outside of coding regions, of selected rare CNVs, their identification remains a challenge for genome analysis. Rare CNVs may potentially represent an important portion of "missing heritability" for human diseases.
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Zhang F, Potocki L, Sampson JB, Liu P, Sanchez-Valle A, Robbins-Furman P, Navarro AD, Wheeler PG, Spence JE, Brasington CK, Withers MA, Lupski JR. Identification of uncommon recurrent Potocki-Lupski syndrome-associated duplications and the distribution of rearrangement types and mechanisms in PTLS. Am J Hum Genet 2010; 86:462-70. [PMID: 20188345 DOI: 10.1016/j.ajhg.2010.02.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 01/26/2010] [Accepted: 02/01/2010] [Indexed: 10/19/2022] Open
Abstract
Nonallelic homologous recombination (NAHR) can mediate recurrent rearrangements in the human genome and cause genomic disorders. Smith-Magenis syndrome (SMS) and Potocki-Lupski syndrome (PTLS) are genomic disorders associated with a 3.7 Mb deletion and its reciprocal duplication in 17p11.2, respectively. In addition to these common recurrent rearrangements, an uncommon recurrent 5 Mb SMS-associated deletion has been identified. However, its reciprocal duplication predicted by the NAHR mechanism had not been identified. Here we report the molecular assays on 74 subjects with PTLS-associated duplications, 35 of whom are newly investigated. By both oligonucleotide-based comparative genomic hybridization and recombination hot spot analyses, we identified two cases of the predicted 5 Mb uncommon recurrent PTLS-associated duplication. Interestingly, the crossovers occur in proximity to a recently delineated allelic homologous recombination (AHR) hot spot-associated sequence motif, further documenting the common hot spot features shared between NAHR and AHR. An additional eight subjects with nonrecurrent PTLS duplications were identified. The smallest region of overlap (SRO) for all of the 74 PTLS duplications examined is narrowed to a 125 kb interval containing only RAI1, a gene recently further implicated in autism. Sequence complexities consistent with DNA replication-based mechanisms were identified in four of eight (50%) newly identified nonrecurrent PTLS duplications. Our findings of the uncommon recurrent PTLS-associated duplication at a relative prevalence reflecting the de novo mutation rate and the distribution of 17p11.2 duplication types in PTLS reveal insights into both the contributions of new mutations and the different underlying mechanisms that generate genomic rearrangements causing genomic disorders.
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Gericke GS. Common chromosomal fragile sites (CFS) may be involved in normal and traumatic cognitive stress memory consolidation and altered nervous system immunity. Med Hypotheses 2010; 74:911-8. [PMID: 20138440 DOI: 10.1016/j.mehy.2009.05.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Revised: 05/22/2009] [Accepted: 05/26/2009] [Indexed: 11/18/2022]
Abstract
Previous reports of specific patterns of increased fragility at common chromosomal fragile sites (CFS) found in association with certain neurobehavioural disorders did not attract attention at the time due to a shift towards molecular approaches to delineate neuropsychiatric disorder candidate genes. Links with miRNA, altered methylation and the origin of copy number variation indicate that CFS region characteristics may be part of chromatinomic mechanisms that are increasingly linked with neuroplasticity and memory. Current reports of large-scale double-stranded DNA breaks in differentiating neurons and evidence of ongoing DNA demethylation of specific gene promoters in adult hippocampus may shed new light on the dynamic epigenetic changes that are increasingly appreciated as contributing to long-term memory consolidation. The expression of immune recombination activating genes in key stress-induced memory regions suggests the adoption by the brain of this ancient pattern recognition and memory system to establish a structural basis for long-term memory through controlled chromosomal breakage at highly specific genomic regions. It is furthermore considered that these mechanisms for management of epigenetic information related to stress memory could be linked, in some instances, with the transfer of the somatically acquired information to the germline. Here, rearranged sequences can be subjected to further selection and possible eventual retrotranscription to become part of the more stable coding machinery if proven to be crucial for survival and reproduction. While linkage of cognitive memory with stress and fear circuitry and memory establishment through structural DNA modification is proposed as a normal process, inappropriate activation of immune-like genomic rearrangement processes through traumatic stress memory may have the potential to lead to undesirable activation of neuro-inflammatory processes. These theories could have a significant impact on the interpretation of risks posed by heredity and the environment and the search for neuropsychiatric candidate genes.
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Affiliation(s)
- G S Gericke
- Department of Biomedical Sciences, Tshwane University of Technology, Brooklyn Square, Pretoria, Gauteng, South Africa.
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28
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Evolution in health and medicine Sackler colloquium: Genomic disorders: a window into human gene and genome evolution. Proc Natl Acad Sci U S A 2010; 107 Suppl 1:1765-71. [PMID: 20080665 DOI: 10.1073/pnas.0906222107] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Gene duplications alter the genetic constitution of organisms and can be a driving force of molecular evolution in humans and the great apes. In this context, the study of genomic disorders has uncovered the essential role played by the genomic architecture, especially low copy repeats (LCRs) or segmental duplications (SDs). In fact, regardless of the mechanism, LCRs can mediate or stimulate rearrangements, inciting genomic instability and generating dynamic and unstable regions prone to rapid molecular evolution. In humans, copy-number variation (CNV) has been implicated in common traits such as neuropathy, hypertension, color blindness, infertility, and behavioral traits including autism and schizophrenia, as well as disease susceptibility to HIV, lupus nephritis, and psoriasis among many other clinical phenotypes. The same mechanisms implicated in the origin of genomic disorders may also play a role in the emergence of segmental duplications and the evolution of new genes by means of genomic and gene duplication and triplication, exon shuffling, exon accretion, and fusion/fission events.
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29
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Marques-Bonet T, Ryder OA, Eichler EE. Sequencing primate genomes: what have we learned? Annu Rev Genomics Hum Genet 2009; 10:355-86. [PMID: 19630567 DOI: 10.1146/annurev.genom.9.081307.164420] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We summarize the progress in whole-genome sequencing and analyses of primate genomes. These emerging genome datasets have broadened our understanding of primate genome evolution revealing unexpected and complex patterns of evolutionary change. This includes the characterization of genome structural variation, episodic changes in the repeat landscape, differences in gene expression, new models regarding speciation, and the ephemeral nature of the recombination landscape. The functional characterization of genomic differences important in primate speciation and adaptation remains a significant challenge. Limited access to biological materials, the lack of detailed phenotypic data and the endangered status of many critical primate species have significantly attenuated research into the genetic basis of primate evolution. Next-generation sequencing technologies promise to greatly expand the number of available primate genome sequences; however, such draft genome sequences will likely miss critical genetic differences within complex genomic regions unless dedicated efforts are put forward to understand the full spectrum of genetic variation.
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Affiliation(s)
- Tomas Marques-Bonet
- Department of Genome Sciences, University of Washington and the Howard Hughes Medical Institute, Seattle, Washington 98105, USA.
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30
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Trombetta B, Cruciani F, Underhill PA, Sellitto D, Scozzari R. Footprints of X-to-Y gene conversion in recent human evolution. Mol Biol Evol 2009; 27:714-25. [PMID: 19812029 DOI: 10.1093/molbev/msp231] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Different X-homologous regions of the male-specific portion of the human Y chromosome (MSY) are characterized by a different content of putative single nucleotide polymorphisms (SNPs), as reported in public databases. The possible role of X-to-Y nonallelic gene conversion in contributing to these differences remains poorly understood. We explored this issue by analyzing sequence variation in three regions of the MSY characterized by a different degree of X-Y similarity and a different density of putative SNPs: the PCDH11Y gene in the X-transposed (X-Y identity 99%, high putative SNP content); the TBL1Y gene in the X-degenerate (X-Y identity 86-88%, low putative SNP content); and VCY genes-containing region in the P8 palindrome (X-Y identity 95%, low putative SNP content). Present findings do not provide any evidence for gene conversion in the PCDH11Y and TBL1Y genes; they also strongly suggest that most putative SNPs of the PCDH11Y gene (and possibly the entire X-transposed region) are most likely X-Y paralogous sequence variants, which have been entered in the databases as SNPs. On the other hand, clear evidence for the VCY genes in the P8 palindrome having acted as an acceptor of X-to-Y gene conversion was obtained. A rate of 1.8 x 10(-7) X-to-Y conversions/bp/year was estimated for these genes. These findings indicate that in the VCY region of the MSY, X-to-Y gene conversion can be highly effective to increase the level of diversity among human Y chromosomes and suggest an additional explanation for the ability of the Y chromosome to retard degradation during evolution. Present data are expected to pave the way for future investigations on the role of nonallelic gene conversion in double-strand break repair and the maintenance of Y chromosome integrity.
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Affiliation(s)
- Beniamino Trombetta
- Dipartimento di Genetica e Biologia Molecolare, Sapienza Università di Roma, Rome, Italy
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31
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Cacabelos R. Pharmacogenomics and therapeutic strategies for dementia. Expert Rev Mol Diagn 2009; 9:567-611. [DOI: 10.1586/erm.09.42] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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32
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The evolution of human segmental duplications and the core duplicon hypothesis. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2009; 74:355-62. [PMID: 19717539 DOI: 10.1101/sqb.2009.74.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Duplicated sequences are important sources of genetic instability and in the evolution of new gene function within species. Hominids have a preponderance of intrachromosomal duplications organized in an interspersed fashion, as opposed to tandem duplications, which are common in other mammalian genomes such as mouse, dog, and cow. Multiple lines of evidence, including sequence divergence, comparative primate genomes, and fluorescence in situ hybridization (FISH) analyses, point to an excess of segmental duplications in the common ancestor of humans and African great apes. We find that much of the interspersed human duplication architecture within chromosomes is focused around common sequence elements referred to as "core duplicons." These cores correspond to the expansion of gene families, some of which show signatures of positive selection and lack orthologs present in other mammalian species. This genomic architecture predisposes apes and humans not only to extensive genetic diversity, but also to large-scale structural diversity mediated by nonallelic homologous recombination. In humans, many de novo large-scale genomic changes mediated by these duplications are associated with neuropsychiatric and neurodevelopmental disease. We propose that the disadvantage of a high rate of new mutations is offset by the selective advantage of newly minted genes within the cores.
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Hastings PJ, Lupski JR, Rosenberg SM, Ira G. Mechanisms of change in gene copy number. Nat Rev Genet 2009. [PMID: 19597530 DOI: 10.1038/nrg2593.mechanisms] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Deletions and duplications of chromosomal segments (copy number variants, CNVs) are a major source of variation between individual humans and are an underlying factor in human evolution and in many diseases, including mental illness, developmental disorders and cancer. CNVs form at a faster rate than other types of mutation, and seem to do so by similar mechanisms in bacteria, yeast and humans. Here we review current models of the mechanisms that cause copy number variation. Non-homologous end-joining mechanisms are well known, but recent models focus on perturbation of DNA replication and replication of non-contiguous DNA segments. For example, cellular stress might induce repair of broken replication forks to switch from high-fidelity homologous recombination to non-homologous repair, thus promoting copy number change.
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Affiliation(s)
- P J Hastings
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
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34
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Hastings PJ, Lupski JR, Rosenberg SM, Ira G. Mechanisms of change in gene copy number. Nat Rev Genet 2009; 10:551-64. [PMID: 19597530 DOI: 10.1038/nrg2593] [Citation(s) in RCA: 846] [Impact Index Per Article: 56.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Deletions and duplications of chromosomal segments (copy number variants, CNVs) are a major source of variation between individual humans and are an underlying factor in human evolution and in many diseases, including mental illness, developmental disorders and cancer. CNVs form at a faster rate than other types of mutation, and seem to do so by similar mechanisms in bacteria, yeast and humans. Here we review current models of the mechanisms that cause copy number variation. Non-homologous end-joining mechanisms are well known, but recent models focus on perturbation of DNA replication and replication of non-contiguous DNA segments. For example, cellular stress might induce repair of broken replication forks to switch from high-fidelity homologous recombination to non-homologous repair, thus promoting copy number change.
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Affiliation(s)
- P J Hastings
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
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Abstract
It is now becoming generally accepted that a significant amount of human genetic variation is due to structural changes of the genome rather than to base-pair changes in the DNA. As for base-pair changes, knowledge of gene and genome function has been informed by structural alterations that convey clinical phenotypes. Genomic disorders are a class of human conditions that result from structural changes of the human genome that convey traits or susceptibility to traits. The path to the delineation of genomic disorders is intertwined with the evolving technologies that have enabled the resolution of human genome analyses to continue increasing. Similarly, the ability to perform high-resolution human genome analysis has fueled the current and future clinical implementation of such discoveries in the evolving field of genome medicine.
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Affiliation(s)
- James R Lupski
- Departments of Molecular and Human Genetics, and Pediatrics, Baylor College of Medicine, and Texas Children's Hospital, Houston, TX 77030, USA.
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36
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A burst of segmental duplications in the genome of the African great ape ancestor. Nature 2009; 457:877-81. [PMID: 19212409 DOI: 10.1038/nature07744] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 12/18/2008] [Indexed: 02/02/2023]
Abstract
It is generally accepted that the extent of phenotypic change between human and great apes is dissonant with the rate of molecular change. Between these two groups, proteins are virtually identical, cytogenetically there are few rearrangements that distinguish ape-human chromosomes, and rates of single-base-pair change and retrotransposon activity have slowed particularly within hominid lineages when compared to rodents or monkeys. Studies of gene family evolution indicate that gene loss and gain are enriched within the primate lineage. Here, we perform a systematic analysis of duplication content of four primate genomes (macaque, orang-utan, chimpanzee and human) in an effort to understand the pattern and rates of genomic duplication during hominid evolution. We find that the ancestral branch leading to human and African great apes shows the most significant increase in duplication activity both in terms of base pairs and in terms of events. This duplication acceleration within the ancestral species is significant when compared to lineage-specific rate estimates even after accounting for copy-number polymorphism and homoplasy. We discover striking examples of recurrent and independent gene-containing duplications within the gorilla and chimpanzee that are absent in the human lineage. Our results suggest that the evolutionary properties of copy-number mutation differ significantly from other forms of genetic mutation and, in contrast to the hominid slowdown of single-base-pair mutations, there has been a genomic burst of duplication activity at this period during human evolution.
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37
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Koszul R, Fischer G. A prominent role for segmental duplications in modeling Eukaryotic genomes. C R Biol 2009; 332:254-66. [DOI: 10.1016/j.crvi.2008.07.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 07/12/2008] [Indexed: 01/22/2023]
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A microhomology-mediated break-induced replication model for the origin of human copy number variation. PLoS Genet 2009; 5:e1000327. [PMID: 19180184 PMCID: PMC2621351 DOI: 10.1371/journal.pgen.1000327] [Citation(s) in RCA: 615] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Chromosome structural changes with nonrecurrent endpoints associated with genomic disorders offer windows into the mechanism of origin of copy number variation (CNV). A recent report of nonrecurrent duplications associated with Pelizaeus-Merzbacher disease identified three distinctive characteristics. First, the majority of events can be seen to be complex, showing discontinuous duplications mixed with deletions, inverted duplications, and triplications. Second, junctions at endpoints show microhomology of 2–5 base pairs (bp). Third, endpoints occur near pre-existing low copy repeats (LCRs). Using these observations and evidence from DNA repair in other organisms, we derive a model of microhomology-mediated break-induced replication (MMBIR) for the origin of CNV and, ultimately, of LCRs. We propose that breakage of replication forks in stressed cells that are deficient in homologous recombination induces an aberrant repair process with features of break-induced replication (BIR). Under these circumstances, single-strand 3′ tails from broken replication forks will anneal with microhomology on any single-stranded DNA nearby, priming low-processivity polymerization with multiple template switches generating complex rearrangements, and eventual re-establishment of processive replication.
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Ghika J. Paleoneurology: Neurodegenerative diseases are age-related diseases of specific brain regions recently developed by homo sapiens. Med Hypotheses 2008; 71:788-801. [DOI: 10.1016/j.mehy.2008.05.034] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 05/01/2008] [Accepted: 05/04/2008] [Indexed: 12/31/2022]
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Ruiz-Herrera A, Robinson TJ. Evolutionary plasticity and cancer breakpoints in human chromosome 3. Bioessays 2008; 30:1126-37. [DOI: 10.1002/bies.20829] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Münch C, Kirsch S, Fernandes AMG, Schempp W. Evolutionary analysis of the highly dynamic CHEK2 duplicon in anthropoids. BMC Evol Biol 2008; 8:269. [PMID: 18831734 PMCID: PMC2566985 DOI: 10.1186/1471-2148-8-269] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 10/02/2008] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Segmental duplications (SDs) are euchromatic portions of genomic DNA (> or = 1 kb) that occur at more than one site within the genome, and typically share a high level of sequence identity (>90%). Approximately 5% of the human genome is composed of such duplicated sequences. Here we report the detailed investigation of CHEK2 duplications. CHEK2 is a multiorgan cancer susceptibility gene encoding a cell cycle checkpoint kinase acting in the DNA-damage response signalling pathway. The continuous presence of the CHEK2 gene in all eukaryotes and its important role in maintaining genome stability prompted us to investigate the duplicative evolution and phylogeny of CHEK2 and its paralogs during anthropoid evolution. RESULTS To study CHEK2 duplicon evolution in anthropoids we applied a combination of comparative FISH and in silico analyses. Our comparative FISH results with a CHEK2 fosmid probe revealed the single-copy status of CHEK2 in New World monkeys, Old World monkeys and gibbons. Whereas a single CHEK2 duplication was detected in orangutan, a multi-site signal pattern indicated a burst of duplication in African great apes and human. Phylogenetic analysis of paralogous and ancestral CHEK2 sequences in human, chimpanzee and rhesus macaque confirmed this burst of duplication, which occurred after the radiation of orangutan and African great apes. In addition, we used inter-species quantitative PCR to determine CHEK2 copy numbers. An amplification of CHEK2 was detected in African great apes and the highest CHEK2 copy number of all analysed species was observed in the human genome. Furthermore, we detected variation in CHEK2 copy numbers within the analysed set of human samples. CONCLUSION Our detailed analysis revealed the highly dynamic nature of CHEK2 duplication during anthropoid evolution. We determined a burst of CHEK2 duplication after the radiation of orangutan and African great apes and identified the highest CHEK2 copy number in human. In conclusion, our analysis of CHEK2 duplicon evolution revealed that SDs contribute to inter-species variation. Furthermore, our qPCR analysis led us to presume CHEK2 copy number variation in human, and molecular diagnostics of the cancer susceptibility gene CHEK2 inside the duplicated region might be hampered by the individual-specific set of duplicons.
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Affiliation(s)
- Claudia Münch
- Institute of Human Genetics and Anthropology, University of Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
| | - Stefan Kirsch
- Institute of Human Genetics and Anthropology, University of Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
| | - António MG Fernandes
- Institute of Human Genetics and Anthropology, University of Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
| | - Werner Schempp
- Institute of Human Genetics and Anthropology, University of Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
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Kirsch S, Pasantes J, Wolf A, Bogdanova N, Münch C, Pennekamp P, Krawczak M, Dworniczak B, Schempp W. Chromosomal evolution of the PKD1 gene family in primates. BMC Evol Biol 2008; 8:263. [PMID: 18822117 PMCID: PMC2564946 DOI: 10.1186/1471-2148-8-263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Accepted: 09/26/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The autosomal dominant polycystic kidney disease (ADPKD) is mostly caused by mutations in the PKD1 (polycystic kidney disease 1) gene located in 16p13.3. Moreover, there are six pseudogenes of PKD1 that are located proximal to the master gene in 16p13.1. In contrast, no pseudogene could be detected in the mouse genome, only a single copy gene on chromosome 17. The question arises how the human situation originated phylogenetically. To address this question we applied comparative FISH-mapping of a human PKD1-containing genomic BAC clone and a PKD1-cDNA clone to chromosomes of a variety of primate species and the dog as a non-primate outgroup species. RESULTS Comparative FISH with the PKD1-cDNA clone clearly shows that in all primate species studied distinct single signals map in subtelomeric chromosomal positions orthologous to the short arm of human chromosome 16 harbouring the master PKD1 gene. Only in human and African great apes, but not in orangutan, FISH with both BAC and cDNA clones reveals additional signal clusters located proximal of and clearly separated from the PKD1 master genes indicating the chromosomal position of PKD1 pseudogenes in 16p of these species, respectively. Indeed, this is in accordance with sequencing data in human, chimpanzee and orangutan. Apart from the master PKD1 gene, six pseudogenes are identified in both, human and chimpanzee, while only a single-copy gene is present in the whole-genome sequence of orangutan. The phylogenetic reconstruction of the PKD1-tree reveals that all human pseudogenes are closely related to the human PKD1 gene, and all chimpanzee pseudogenes are closely related to the chimpanzee PKD1 gene. However, our statistical analyses provide strong indication that gene conversion events may have occurred within the PKD1 family members of human and chimpanzee, respectively. CONCLUSION PKD1 must have undergone amplification very recently in hominid evolution. Duplicative transposition of the PKD1 gene and further amplification and evolution of the PKD1 pseudogenes may have arisen in a common ancestor of Homo, Pan and Gorilla approximately 8 MYA. Reticulate evolutionary processes such as gene conversion and non-allelic homologous recombination (NAHR) may have resulted in concerted evolution of PKD1 family members in human and chimpanzee and, thus, simulate an independent evolution of the PKD1 pseudogenes from their master PKD1 genes in human and chimpanzee.
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Affiliation(s)
- Stefan Kirsch
- Institut für Humangenetik und Anthropologie, Universität Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
| | - Juanjo Pasantes
- Institut für Humangenetik und Anthropologie, Universität Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
- Department of Biochemistry, Genetics & Immunology, University of Vigo, E-36200 Vigo, Spain
| | - Andreas Wolf
- Institut für Medizinische Informatik und Statistik, Universität Kiel, Brunswiker Str. 10, 24105 Kiel, Germany
| | - Nadia Bogdanova
- Institut für Humangenetik, Universität Münster, Vesaliusweg 12-14, 48129 Münster, Germany
| | - Claudia Münch
- Institut für Humangenetik und Anthropologie, Universität Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
| | - Petra Pennekamp
- Institut für Humangenetik, Universität Münster, Vesaliusweg 12-14, 48129 Münster, Germany
| | - Michael Krawczak
- Institut für Medizinische Informatik und Statistik, Universität Kiel, Brunswiker Str. 10, 24105 Kiel, Germany
| | - Bernd Dworniczak
- Institut für Humangenetik, Universität Münster, Vesaliusweg 12-14, 48129 Münster, Germany
| | - Werner Schempp
- Institut für Humangenetik und Anthropologie, Universität Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
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The genomic distribution of intraspecific and interspecific sequence divergence of human segmental duplications relative to human/chimpanzee chromosomal rearrangements. BMC Genomics 2008; 9:384. [PMID: 18699995 PMCID: PMC2542386 DOI: 10.1186/1471-2164-9-384] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Accepted: 08/12/2008] [Indexed: 11/20/2022] Open
Abstract
Background It has been suggested that chromosomal rearrangements harbor the molecular footprint of the biological phenomena which they induce, in the form, for instance, of changes in the sequence divergence rates of linked genes. So far, all the studies of these potential associations have focused on the relationship between structural changes and the rates of evolution of single-copy DNA and have tried to exclude segmental duplications (SDs). This is paradoxical, since SDs are one of the primary forces driving the evolution of structure and function in our genomes and have been linked not only with novel genes acquiring new functions, but also with overall higher DNA sequence divergence and major chromosomal rearrangements. Results Here we take the opposite view and focus on SDs. We analyze several of the features of SDs, including the rates of intraspecific divergence between paralogous copies of human SDs and of interspecific divergence between human SDs and chimpanzee DNA. We study how divergence measures relate to chromosomal rearrangements, while considering other factors that affect evolutionary rates in single copy DNA. Conclusion We find that interspecific SD divergence behaves similarly to divergence of single-copy DNA. In contrast, old and recent paralogous copies of SDs do present different patterns of intraspecific divergence. Also, we show that some relatively recent SDs accumulate in regions that carry inversions in sister lineages.
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Lee TM, Lipovich L. Structural differences of orthologous genes: insights from human-primate comparisons. Genomics 2008; 92:134-43. [PMID: 18606524 DOI: 10.1016/j.ygeno.2008.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Revised: 04/16/2008] [Accepted: 05/02/2008] [Indexed: 01/15/2023]
Abstract
The genomic basis of phenotypic distinctions between humans and nonhuman primates remains insufficiently explained. We hypothesized that interspecies structural differences of orthologous genes can cause such distinctions and searched protein-coding genes conserved between humans and nonhuman primates for species-specific initial and terminal exons. We inferred gene structure differences from genomic locations where portions of primate transcripts aligned with the human genome outside of any human exons. Of 22,466 high-confidence FANTOM3 human transcriptional units, 7424 (33%) had nonhuman primate full-length cDNA support. One hundred eighty-three of the loci contained 68,424 bp of sequence exonic in nonhuman primates but not humans. Fifty-four of 183 included species-specific portions of protein-coding regions. Six genes had evidence of intergenic splicing in a nonhuman primate but not in human. It is imperative that primate transcriptome projects be accelerated on par with genome projects to understand better interspecies gene structure distinctions.
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Affiliation(s)
- Tuan Meng Lee
- School of Computer Engineering, Nanyang Technological University, Singapore
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Kehrer-Sawatzki H, Cooper DN. Molecular mechanisms of chromosomal rearrangement during primate evolution. Chromosome Res 2008; 16:41-56. [PMID: 18293104 DOI: 10.1007/s10577-007-1207-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Breakpoint analysis of the large chromosomal rearrangements which have occurred during primate evolution promises to yield new insights into the underlying mechanisms of mutagenesis. Comparison of these evolutionary breakpoints with those that are disease-associated in humans, and which occur during either meiotic or mitotic cell division, should help to identify basic mechanistic similarities as well as differences. It has recently become clear that segmental duplications (SDs) have had a very significant impact on genome plasticity during primate evolution. In comparisons of the human and chimpanzee genomes, SDs have been found in flanking regions of 70-80% of inversions and approximately 40% of deletions/duplications. A strong spatial association between primate-specific breakpoints and SDs has also become evident from comparisons of human with other mammalian genomes. The lineage-specific hyperexpansion of certain SDs observed in the genomes of human, chimpanzee, gorilla and gibbon is indicative of the intrinsic instability of some SDs in primates. However, since many primate-specific breakpoints map to regions lacking SDs, but containing interspersed high-copy repetitive sequence elements such as SINEs, LINEs, LTRs, alpha-satellites and (AT)( n ) repeats, we may infer that a range of different molecular mechanisms have probably been involved in promoting chromosomal breakage during the evolution of primate genomes.
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Abstract
The extent of copy-number variation (CNV) in the human genome has been appreciated only recently. Nevertheless, for almost four decades, gene duplication has been a prevailing hypothesis for evolutionary change. Recently, gene CNV spanning 60 million years of human and primate evolution has been determined enabling lineage-specific gene CNV to be identified. Primate lineage-specific gene CNV studies reveal that almost one third of all human genes exhibit a copy-number change in one or more primate species. Intriguingly, human lineage-specific gene amplification can be correlated to the emergence of human-specific traits such as cognition and endurance running.
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Affiliation(s)
- James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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Darai-Ramqvist E, Sandlund A, Müller S, Klein G, Imreh S, Kost-Alimova M. Segmental duplications and evolutionary plasticity at tumor chromosome break-prone regions. Genome Res 2008; 18:370-9. [PMID: 18230801 DOI: 10.1101/gr.7010208] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have previously found that the borders of evolutionarily conserved chromosomal regions often coincide with tumor-associated deletion breakpoints within human 3p12-p22. Moreover, a detailed analysis of a frequently deleted region at 3p21.3 (CER1) showed associations between tumor breaks and gene duplications. We now report on the analysis of 54 chromosome 3 breaks by multipoint FISH (mpFISH) in 10 carcinoma-derived cell lines. The centromeric region was broken in five lines. In lines with highly complex karyotypes, breaks were clustered near known fragile sites, FRA3B, FRA3C, and FRA3D (three lines), and in two other regions: 3p12.3-p13 ( approximately 75 Mb position) and 3q21.3-q22.1 ( approximately 130 Mb position) (six lines). All locations are shown based on NCBI Build 36.1 human genome sequence. The last two regions participated in three of four chromosome 3 inversions during primate evolution. Regions at 75, 127, and 131 Mb positions carry a large ( approximately 250 kb) segmental duplication (tumor break-prone segmental duplication [TBSD]). TBSD homologous sequences were found at 15 sites on different chromosomes. They were located within bands frequently involved in carcinoma-associated breaks. Thirteen of them have been involved in inversions during primate evolution; 10 were reused by breaks during mammalian evolution; 14 showed copy number polymorphism in man. TBSD sites showed an increase in satellite repeats, retrotransposed sequences, and other segmental duplications. We propose that the instability of these sites stems from specific organization of the chromosomal region, associated with location at a boundary between different CG-content isochores and with the presence of TBSDs and "instability elements," including satellite repeats and retroviral sequences.
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Affiliation(s)
- Eva Darai-Ramqvist
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm SE-171 77, Sweden
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Abstract
Pharmacological treatment in Alzheimer's disease (AD) accounts for 10-20% of direct costs, and fewer than 20% of AD patients are moderate responders to conventional drugs (donepezil, rivastigmine, galantamine, memantine), with doubtful cost-effectiveness. Both AD pathogenesis and drug metabolism are genetically regulated complex traits in which hundreds of genes cooperatively participate. Structural genomics studies demonstrated that more than 200 genes might be involved in AD pathogenesis regulating dysfunctional genetic networks leading to premature neuronal death. The AD population exhibits a higher genetic variation rate than the control population, with absolute and relative genetic variations of 40-60% and 0.85-1.89%, respectively. AD patients also differ in their genomic architecture from patients with other forms of dementia. Functional genomics studies in AD revealed that age of onset, brain atrophy, cerebrovascular hemodynamics, brain bioelectrical activity, cognitive decline, apoptosis, immune function, lipid metabolism dyshomeostasis, and amyloid deposition are associated with AD-related genes. Pioneering pharmacogenomics studies also demonstrated that the therapeutic response in AD is genotype-specific, with apolipoprotein E (APOE) 4/4 carriers the worst responders to conventional treatments. About 10-20% of Caucasians are carriers of defective cytochrome P450 (CYP) 2D6 polymorphic variants that alter the metabolism and effects of AD drugs and many psychotropic agents currently administered to patients with dementia. There is a moderate accumulation of AD-related genetic variants of risk in CYP2D6 poor metabolizers (PMs) and ultrarapid metabolizers (UMs), who are the worst responders to conventional drugs. The association of the APOE-4 allele with specific genetic variants of other genes (e.g., CYP2D6, angiotensin-converting enzyme [ACE]) negatively modulates the therapeutic response to multifactorial treatments affecting cognition, mood, and behavior. Pharmacogenetic and pharmacogenomic factors may account for 60-90% of drug variability in drug disposition and pharmacodynamics. The incorporation of pharmacogenetic/pharmacogenomic protocols to AD research and clinical practice can foster therapeutics optimization by helping to develop cost-effective pharmaceuticals and improving drug efficacy and safety.
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Affiliation(s)
- Ramón Cacabelos
- EuroEspes Biomedical Research Center, Institute for CNS Disorders, Bergondo, Coruña, Spain
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Portin P. Evolution of man in the light of molecular genetics: a review. Part I. Our evolutionary history and genomics. Hereditas 2007; 144:80-95. [PMID: 17663700 DOI: 10.1111/j.2007.0018-0661.02003.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The discovery in the mid 1970s of efficient methods of DNA sequencing and their subsequent development into more and more rapid procedures followed by sequencing the genomes of many species, including man in 2001, revolutionised the whole of biology. Remarkably, new light could be cast on the evolutionary relations of different species, and the tempo and mode of evolution within a given species, notably man, could quantitatively be illuminated including ongoing evolution possibly involving also the size of the brains. This review is a short summary of the results of the molecular genetic investigations of human evolution including the time and place of the formation of our species, our evolutionary relation to the closest living species relatives as well as extinct forms of the genus Homo. The nature and amount of genetic polymorphism in man is also considered with special emphasis on the causes of this variation, and the role of natural selection in human evolution. A consensus about the mosaic nature of our genome and the rather dynamic structure of our ancestral population is gradually emerging. The modern gene pool has most likely been contributed to several different ancestral demes either before or after the emergence of the anatomically modern human phenotype in the extent that even the nature of the evolutionary lineage leading to the anatomically modern man as a distinct biological species is disputable. Regulation of the function of genes, as well as the evolution of brains will be dealt with in the second part of this review.
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Affiliation(s)
- Petter Portin
- Laboratory of Genetics, Department of Biology, University of Turku, Turku, Finland.
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