1
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Redaelli S, Grati FR, Tritto V, Giannuzzi G, Recalcati MP, Sala E, Villa N, Crosti F, Roversi G, Malvestiti F, Zanatta V, Repetti E, Rodeschini O, Valtorta C, Catusi I, Romitti L, Martinoli E, Conconi D, Dalprà L, Lavitrano M, Riva P, Bentivegna A. Olfactory receptor genes and chromosome 11 structural aberrations: Players or spectators? HGG ADVANCES 2024; 5:100261. [PMID: 38160254 PMCID: PMC10820794 DOI: 10.1016/j.xhgg.2023.100261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/28/2023] [Accepted: 12/28/2023] [Indexed: 01/03/2024] Open
Abstract
The largest multi-gene family in metazoans is the family of olfactory receptor (OR) genes. Human ORs are organized in clusters over most chromosomes and seem to include >0.1% the human genome. Because 369 out of 856 OR genes are mapped on chromosome 11 (HSA11), we sought to determine whether they mediate structural rearrangements involving this chromosome. To this aim, we analyzed 220 specimens collected during diagnostic procedures involving structural rearrangements of chromosome 11. A total of 222 chromosomal abnormalities were included, consisting of inversions, deletions, translocations, duplications, and one insertion, detected by conventional chromosome analysis and/or fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (array-CGH). We verified by bioinformatics and statistical approaches the occurrence of breakpoints in cytobands with or without OR genes. We found that OR genes are not involved in chromosome 11 reciprocal translocations, suggesting that different DNA motifs and mechanisms based on homology or non-homology recombination can cause chromosome 11 structural alterations. We also considered the proximity between the chromosomal territories of chromosome 11 and its partner chromosomes involved in the translocations by using the deposited Hi-C data concerning the possible occurrence of chromosome interactions. Interestingly, most of the breakpoints are located in regions highly involved in chromosome interactions. Further studies should be carried out to confirm the potential role of chromosome territories' proximity in promoting genome structural variation, so fundamental in our understanding of the molecular basis of medical genetics and evolutionary genetics.
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Affiliation(s)
- Serena Redaelli
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
| | - Francesca Romana Grati
- R&D, Cytogenetics, Molecular Genetics and Medical Genetics Unit, Toma Advanced Biomedical Assays S.p.A. (ImpactLab), 21052 Busto Arsizio, Italy
| | - Viviana Tritto
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20122 Milan, Italy
| | | | - Maria Paola Recalcati
- IRCCS Istituto Auxologico Italiano, Medical Cytogenetics Laboratory, 20095 Cusano Milanino, Italy
| | - Elena Sala
- UC Medical Genetics, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy
| | - Nicoletta Villa
- UC Medical Genetics, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy
| | - Francesca Crosti
- UC Medical Genetics, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy
| | - Gaia Roversi
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; UC Medical Genetics, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy
| | - Francesca Malvestiti
- R&D, Cytogenetics, Molecular Genetics and Medical Genetics Unit, Toma Advanced Biomedical Assays S.p.A. (ImpactLab), 21052 Busto Arsizio, Italy
| | - Valentina Zanatta
- R&D, Cytogenetics, Molecular Genetics and Medical Genetics Unit, Toma Advanced Biomedical Assays S.p.A. (ImpactLab), 21052 Busto Arsizio, Italy
| | - Elena Repetti
- R&D, Cytogenetics, Molecular Genetics and Medical Genetics Unit, Toma Advanced Biomedical Assays S.p.A. (ImpactLab), 21052 Busto Arsizio, Italy
| | - Ornella Rodeschini
- IRCCS Istituto Auxologico Italiano, Medical Cytogenetics Laboratory, 20095 Cusano Milanino, Italy
| | - Chiara Valtorta
- IRCCS Istituto Auxologico Italiano, Medical Cytogenetics Laboratory, 20095 Cusano Milanino, Italy
| | - Ilaria Catusi
- IRCCS Istituto Auxologico Italiano, Medical Cytogenetics Laboratory, 20095 Cusano Milanino, Italy
| | - Lorenza Romitti
- Pathology and Cytogenetics Laboratory, Clinical Pathology Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20162 Milan, Italy
| | - Emanuela Martinoli
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20122 Milan, Italy
| | - Donatella Conconi
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
| | - Leda Dalprà
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; UC Medical Genetics, Fondazione IRCCS San Gerardo dei Tintori, 20900 Monza, Italy
| | - Marialuisa Lavitrano
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy
| | - Paola Riva
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20122 Milan, Italy
| | - Angela Bentivegna
- School of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy.
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2
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Romdhane L, Kefi S, Mezzi N, Abassi N, Jmel H, Romdhane S, Shan J, Chouchane L, Abdelhak S. Ethnic and functional differentiation of copy number polymorphisms in Tunisian and HapMap population unveils insights on genome organizational plasticity. Sci Rep 2024; 14:4654. [PMID: 38409353 PMCID: PMC10897484 DOI: 10.1038/s41598-024-54749-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 02/15/2024] [Indexed: 02/28/2024] Open
Abstract
Admixture mapping has been useful in identifying genetic variations linked to phenotypes, adaptation and diseases. Copy number variations (CNVs) represents genomic structural variants spanning large regions of chromosomes reaching several megabases. In this investigation, the "Canary" algorithm was applied to 102 Tunisian samples and 991 individuals from eleven HapMap III populations to genotype 1279 copy number polymorphisms (CNPs). In this present work, we investigate the Tunisian population structure using the CNP makers previously identified among Tunisian. The study revealed that Sub-Saharan African populations exhibited the highest diversity with the highest proportions of allelic CNPs. Among all the African populations, Tunisia showed the least diversity. Individual ancestry proportions computed using STRUCTURE analysis revealed a major European component among Tunisians with lesser contribution from Sub-Saharan Africa and Asia. Population structure analysis indicated the genetic proximity with Europeans and noticeable distance from the Sub-Saharan African and East Asian clusters. Seven genes harbouring Tunisian high-frequent CNPs were identified known to be associated with 9 Mendelian diseases and/or phenotypes. Functional annotation of genes under selection highlighted a noteworthy enrichment of biological processes to receptor pathway and activity as well as glutathione metabolism. Additionally, pathways of potential concern for health such as drug metabolism, infectious diseases and cancers exhibited significant enrichment. The distinctive genetic makeup of the Tunisians might have been influenced by various factors including natural selection and genetic drift, resulting in the development of distinct genetic variations playing roles in specific biological processes. Our research provides a justification for focusing on the exclusive genome organization of this population and uncovers previously overlooked elements of the genome.
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Affiliation(s)
- Lilia Romdhane
- Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, University of Tunis El Manar, Tunis, Tunisia.
- Department of Biology, Faculty of Sciences of Bizerte, University of Carthage, Zarzouna, Tunisia.
| | - Sameh Kefi
- Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Nessrine Mezzi
- Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Najla Abassi
- Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Haifa Jmel
- Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Safa Romdhane
- Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Jingxuan Shan
- Laboratory of Genetic Medicine and Immunology, Weill Cornell Medicine-Qatar, Education City-Qatar Foundation, Doha, Qatar
- Department of Genetic Medicine, Weill Cornell Medicine, New York, NY, USA
- Genetic Intelligence Laboratory, Weill Cornell Medicine in Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Lotfi Chouchane
- Laboratory of Genetic Medicine and Immunology, Weill Cornell Medicine-Qatar, Education City-Qatar Foundation, Doha, Qatar
- Department of Genetic Medicine, Weill Cornell Medicine, New York, NY, USA
- Genetic Intelligence Laboratory, Weill Cornell Medicine in Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Sonia Abdelhak
- Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, University of Tunis El Manar, Tunis, Tunisia
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3
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Romdhane L, Mezzi N, Dallali H, Messaoud O, Shan J, Fakhro KA, Kefi R, Chouchane L, Abdelhak S. A map of copy number variations in the Tunisian population: a valuable tool for medical genomics in North Africa. NPJ Genom Med 2021; 6:3. [PMID: 33420067 PMCID: PMC7794582 DOI: 10.1038/s41525-020-00166-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 11/18/2020] [Indexed: 11/24/2022] Open
Abstract
Copy number variation (CNV) is considered as the most frequent type of structural variation in the human genome. Some CNVs can act on human phenotype diversity, encompassing rare Mendelian diseases and genomic disorders. The North African populations remain underrepresented in public genetic databases in terms of single-nucleotide variants as well as for larger genomic mutations. In this study, we present the first CNV map for a North African population using the Affymetrix Genome-Wide SNP (single-nucleotide polymorphism) array 6.0 array genotyping intensity data to call CNVs in 102 Tunisian healthy individuals. Two softwares, PennCNV and Birdsuite, were used to call CNVs in order to provide reliable data. Subsequent bioinformatic analyses were performed to explore their features and patterns. The CNV map of the Tunisian population includes 1083 CNVs spanning 61.443 Mb of the genome. The CNV length ranged from 1.017 kb to 2.074 Mb with an average of 56.734 kb. Deletions represent 57.43% of the identified CNVs, while duplications and the mixed loci are less represented. One hundred and three genes disrupted by CNVs are reported to cause 155 Mendelian diseases/phenotypes. Drug response genes were also reported to be affected by CNVs. Data on genes overlapped by deletions and duplications segments and the sequence properties in and around them also provided insights into the functional and health impacts of CNVs. These findings represent valuable clues to genetic diversity and personalized medicine in the Tunisian population as well as in the ethnically similar populations from North Africa.
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Affiliation(s)
- Lilia Romdhane
- Biomedical Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, Tunis, Tunisia.
- Department of Biology, Faculty of Science of Bizerte, Jarzouna, Tunisia.
| | - Nessrine Mezzi
- Biomedical Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, Tunis, Tunisia
| | - Hamza Dallali
- Biomedical Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, Tunis, Tunisia
| | - Olfa Messaoud
- Biomedical Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, Tunis, Tunisia
| | - Jingxuan Shan
- Department of Genetic Medicine, Weill Cornell Medicine, New York, NY, USA
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
- Genetic Intelligence Laboratory, Weill Cornell Medicine in Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Khalid A Fakhro
- Department of Genetic Medicine, Weill Cornell Medical College in Qatar, Doha, Qatar
- Department of Human Genetics, Sidra Medicine, Doha, Qatar
| | - Rym Kefi
- Biomedical Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, Tunis, Tunisia
| | - Lotfi Chouchane
- Department of Genetic Medicine, Weill Cornell Medicine, New York, NY, USA
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
- Genetic Intelligence Laboratory, Weill Cornell Medicine in Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Sonia Abdelhak
- Biomedical Genomics and Oncogenetics Laboratory (LR16IPT05), Institut Pasteur de Tunis, Tunis, Tunisia
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4
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Young E, Pastor S, Rajagopalan R, McCaffrey J, Sibert J, Mak ACY, Kwok PY, Riethman H, Xiao M. High-throughput single-molecule mapping links subtelomeric variants and long-range haplotypes with specific telomeres. Nucleic Acids Res 2017; 45:e73. [PMID: 28180280 PMCID: PMC5605236 DOI: 10.1093/nar/gkx017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 02/07/2017] [Indexed: 01/22/2023] Open
Abstract
Accurate maps and DNA sequences for human subtelomere regions, along with detailed knowledge of subtelomere variation and long-range telomere-terminal haplotypes in individuals, are critical for understanding telomere function and its roles in human biology. Here, we use a highly automated whole genome mapping technology in nano-channel arrays to analyze large terminal human chromosome segments extending from chromosome-specific subtelomere sequences through subtelomeric repeat regions to terminal (TTAGGG)n repeat tracts. We establish detailed maps for subtelomere gap regions in the human reference sequence, detect many new large subtelomeric variants and demonstrate the feasibility of long-range haplotyping through segmentally duplicated subtelomere regions. These features make the method a uniquely valuable new tool for improving the quality of genome assemblies in complex DNA regions. Based on single molecule mapping of telomere-terminal DNA fragments, we provide proof of principle for a novel method to estimate telomere lengths linked to distinguishable telomeric haplotypes; this single-telomere genotyping method may ultimately enable delineation of human cis elements involved in telomere length regulation.
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Affiliation(s)
- Eleanor Young
- Drexel University, School of Biomedical Engineering, Philadelphia, PA, 19104 USA
| | - Steven Pastor
- Drexel University, School of Biomedical Engineering, Philadelphia, PA, 19104 USA
| | | | - Jennifer McCaffrey
- Drexel University, School of Biomedical Engineering, Philadelphia, PA, 19104 USA
| | - Justin Sibert
- Drexel University, School of Biomedical Engineering, Philadelphia, PA, 19104 USA
| | - Angel C Y Mak
- Cardiovascular Research Institute, University of California, San Francisco, CA, 94158 USA
| | - Pui-Yan Kwok
- Cardiovascular Research Institute, University of California, San Francisco, CA, 94158 USA
| | - Harold Riethman
- Old Dominion University, Medical Diagnostic and Translational Sciences, Norfolk, VA, 23529 USA
| | - Ming Xiao
- Drexel University, School of Biomedical Engineering, Philadelphia, PA, 19104 USA.,Institute of Molecular Medicine and Infectious Disease, School of Medicine, Drexel University, Philadelphia, PA, 19102 USA
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5
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Noll AC, Miller NA, Smith LD, Yoo B, Fiedler S, Cooley LD, Willig LK, Petrikin JE, Cakici J, Lesko J, Newton A, Detherage K, Thiffault I, Saunders CJ, Farrow EG, Kingsmore SF. Clinical detection of deletion structural variants in whole-genome sequences. NPJ Genom Med 2016; 1:16026. [PMID: 29263817 PMCID: PMC5685307 DOI: 10.1038/npjgenmed.2016.26] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 06/22/2016] [Accepted: 06/22/2016] [Indexed: 12/13/2022] Open
Abstract
Optimal management of acutely ill infants with monogenetic diseases requires rapid identification of causative haplotypes. Whole-genome sequencing (WGS) has been shown to identify pathogenic nucleotide variants in such infants. Deletion structural variants (DSVs, >50 nt) are implicated in many genetic diseases, and tools have been designed to identify DSVs using short-read WGS. Optimisation and integration of these tools into a WGS pipeline could improve diagnostic sensitivity and specificity of WGS. In addition, it may improve turnaround time when compared with current CNV assays, enhancing utility in acute settings. Here we describe DSV detection methods for use in WGS for rapid diagnosis in acutely ill infants: SKALD (Screening Konsensus and Annotation of Large Deletions) combines calls from two tools (Breakdancer and GenomeStrip) with calibrated filters and clinical interpretation rules. In four WGS runs, the average analytic precision (positive predictive value) of SKALD was 78%, and recall (sensitivity) was 27%, when compared with validated reference DSV calls. When retrospectively applied to a cohort of 36 families with acutely ill infants SKALD identified causative DSVs in two. The first was heterozygous deletion of exons 1–3 of MMP21 in trans with a heterozygous frame-shift deletion in two siblings with transposition of the great arteries and heterotaxy. In a newborn female with dysmorphic features, ventricular septal defect and persistent pulmonary hypertension, SKALD identified the breakpoints of a heterozygous, de novo 1p36.32p36.13 deletion. In summary, consensus DSV calling, implemented in an 8-h computational pipeline with parameterised filtering, has the potential to increase the diagnostic yield of WGS in acutely ill neonates and discover novel disease genes.
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Affiliation(s)
- Aaron C Noll
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA.,Heartland Institute for Clinical and Translational Research, University of Kansas Medical Center, Kansas City, KS, USA.,Department of Pediatrics, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Neil A Miller
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Laurie D Smith
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA.,Heartland Institute for Clinical and Translational Research, University of Kansas Medical Center, Kansas City, KS, USA.,Department of Pediatrics, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Byunggil Yoo
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Stephanie Fiedler
- Department of Pathology, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Linda D Cooley
- Department of Pediatrics, University of Missouri-Kansas City, Kansas City, MO, USA.,Department of Pathology, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Laurel K Willig
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA.,Department of Pediatrics, Children's Mercy Kansas City, Kansas City, MO, USA.,Department of Pediatrics, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Josh E Petrikin
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA.,Department of Pediatrics, Children's Mercy Kansas City, Kansas City, MO, USA.,Department of Pediatrics, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Julie Cakici
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - John Lesko
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Angela Newton
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Kali Detherage
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Isabelle Thiffault
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA.,Department of Pediatrics, University of Missouri-Kansas City, Kansas City, MO, USA.,Department of Pathology, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Carol J Saunders
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA.,Department of Pediatrics, University of Missouri-Kansas City, Kansas City, MO, USA.,Department of Pathology, Children's Mercy Kansas City, Kansas City, MO, USA
| | - Emily G Farrow
- Center for Pediatric Genomic Medicine, Children's Mercy Kansas City, Kansas City, MO, USA.,Department of Pediatrics, Children's Mercy Kansas City, Kansas City, MO, USA.,Department of Pediatrics, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Stephen F Kingsmore
- Heartland Institute for Clinical and Translational Research, University of Kansas Medical Center, Kansas City, KS, USA.,Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
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6
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Mason-Suares H, Landry L, S. Lebo M. Detecting Copy Number Variation via Next Generation Technology. CURRENT GENETIC MEDICINE REPORTS 2016. [DOI: 10.1007/s40142-016-0091-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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7
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Rogers RL. Chromosomal Rearrangements as Barriers to Genetic Homogenization between Archaic and Modern Humans. Mol Biol Evol 2015; 32:3064-78. [PMID: 26399483 DOI: 10.1093/molbev/msv204] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Chromosomal rearrangements, which shuffle DNA throughout the genome, are an important source of divergence across taxa. Using a paired-end read approach with Illumina sequence data for archaic humans, I identify changes in genome structure that occurred recently in human evolution. Hundreds of rearrangements indicate genomic trafficking between the sex chromosomes and autosomes, raising the possibility of sex-specific changes. Additionally, genes adjacent to genome structure changes in Neanderthals are associated with testis-specific expression, consistent with evolutionary theory that new genes commonly form with expression in the testes. I identify one case of new-gene creation through transposition from the Y chromosome to chromosome 10 that combines the 5'-end of the testis-specific gene Fank1 with previously untranscribed sequence. This new transcript experienced copy number expansion in archaic genomes, indicating rapid genomic change. Among rearrangements identified in Neanderthals, 13% are transposition of selfish genetic elements, whereas 32% appear to be ectopic exchange between repeats. In Denisovan, the pattern is similar but numbers are significantly higher with 18% of rearrangements reflecting transposition and 40% ectopic exchange between distantly related repeats. There is an excess of divergent rearrangements relative to polymorphism in Denisovan, which might result from nonuniform rates of mutation, possibly reflecting a burst of transposable element activity in the lineage that led to Denisovan. Finally, loci containing genome structure changes show diminished rates of introgression from Neanderthals into modern humans, consistent with the hypothesis that rearrangements serve as barriers to gene flow during hybridization. Together, these results suggest that this previously unidentified source of genomic variation has important biological consequences in human evolution.
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Affiliation(s)
- Rebekah L Rogers
- Department of Integrative Biology, University of California, Berkeley
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8
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Dilthey A, Cox C, Iqbal Z, Nelson MR, McVean G. Improved genome inference in the MHC using a population reference graph. Nat Genet 2015; 47:682-8. [PMID: 25915597 PMCID: PMC4449272 DOI: 10.1038/ng.3257] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 03/03/2015] [Indexed: 12/21/2022]
Abstract
Although much is known about human genetic variation, such information is typically ignored in assembling new genomes. Instead, reads are mapped to a single reference, which can lead to poor characterization of regions of high sequence or structural diversity. We introduce a population reference graph, which combines multiple reference sequences and catalogs of variation. The genomes of new samples are reconstructed as paths through the graph using an efficient hidden Markov model, allowing for recombination between different haplotypes and additional variants. By applying the method to the 4.5-Mb extended MHC region on human chromosome 6, combining 8 assembled haplotypes, the sequences of known classical HLA alleles and 87,640 SNP variants from the 1000 Genomes Project, we demonstrate using simulations, SNP genotyping, and short-read and long-read data how the method improves the accuracy of genome inference and identified regions where the current set of reference sequences is substantially incomplete.
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Affiliation(s)
- Alexander Dilthey
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Charles Cox
- Department of Quantitative Sciences, GlaxoSmithKline, Stevenage, UK
| | - Zamin Iqbal
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Matthew R Nelson
- Department of Quantitative Sciences, GlaxoSmithKline, Research Triangle Park, North Carolina, USA
| | - Gil McVean
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
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9
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Persuy MA, Sanz G, Tromelin A, Thomas-Danguin T, Gibrat JF, Pajot-Augy E. Mammalian olfactory receptors: molecular mechanisms of odorant detection, 3D-modeling, and structure-activity relationships. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 130:1-36. [PMID: 25623335 DOI: 10.1016/bs.pmbts.2014.11.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
This chapter describes the main characteristics of olfactory receptor (OR) genes of vertebrates, including generation of this large multigenic family and pseudogenization. OR genes are compared in relation to evolution and among species. OR gene structure and selection of a given gene for expression in an olfactory sensory neuron (OSN) are tackled. The specificities of OR proteins, their expression, and their function are presented. The expression of OR proteins in locations other than the nasal cavity is regulated by different mechanisms, and ORs display various additional functions. A conventional olfactory signal transduction cascade is observed in OSNs, but individual ORs can also mediate different signaling pathways, through the involvement of other molecular partners and depending on the odorant ligand encountered. ORs are engaged in constitutive dimers. Ligand binding induces conformational changes in the ORs that regulate their level of activity depending on odorant dose. When present, odorant binding proteins induce an allosteric modulation of OR activity. Since no 3D structure of an OR has been yet resolved, modeling has to be performed using the closest G-protein-coupled receptor 3D structures available, to facilitate virtual ligand screening using the models. The study of odorant binding modes and affinities may infer best-bet OR ligands, to be subsequently checked experimentally. The relationship between spatial and steric features of odorants and their activity in terms of perceived odor quality are also fields of research that development of computing tools may enhance.
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Affiliation(s)
- Marie-Annick Persuy
- INRA UR 1197 NeuroBiologie de l'Olfaction, Domaine de Vilvert, Jouy-en-Josas, France
| | - Guenhaël Sanz
- INRA UR 1197 NeuroBiologie de l'Olfaction, Domaine de Vilvert, Jouy-en-Josas, France
| | - Anne Tromelin
- INRA UMR 1129 Flaveur, Vision et Comportement du Consommateur, Dijon, France
| | | | - Jean-François Gibrat
- INRA UR1077 Mathématique Informatique et Génome, Domaine de Vilvert, Jouy-en-Josas, France
| | - Edith Pajot-Augy
- INRA UR 1197 NeuroBiologie de l'Olfaction, Domaine de Vilvert, Jouy-en-Josas, France.
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10
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Ono S, Domschke K, Deckert J. Genomic structural variation in affective, anxiety, and stress-related disorders. J Neural Transm (Vienna) 2014; 122:69-78. [DOI: 10.1007/s00702-014-1309-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 09/02/2014] [Indexed: 12/18/2022]
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11
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12
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Alkan C, Coe BP, Eichler EE. Genome structural variation discovery and genotyping. Nat Rev Genet 2011; 12:363-76. [PMID: 21358748 DOI: 10.1038/nrg2958] [Citation(s) in RCA: 957] [Impact Index Per Article: 73.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Comparisons of human genomes show that more base pairs are altered as a result of structural variation - including copy number variation - than as a result of point mutations. Here we review advances and challenges in the discovery and genotyping of structural variation. The recent application of massively parallel sequencing methods has complemented microarray-based methods and has led to an exponential increase in the discovery of smaller structural-variation events. Some global discovery biases remain, but the integration of experimental and computational approaches is proving fruitful for accurate characterization of the copy, content and structure of variable regions. We argue that the long-term goal should be routine, cost-effective and high quality de novo assembly of human genomes to comprehensively assess all classes of structural variation.
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Affiliation(s)
- Can Alkan
- Department of Genome Sciences, University of Washington School of Medicine, Foege S413C, 3720 15th Ave NE, Seattle, Washington, USA
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13
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Abstract
Through cultural innovation and changes in habitat and ecology, there have been a number of major dietary shifts in human evolution, including meat eating, cooking, and those associated with plant and animal domestication. The identification of signatures of adaptations to such dietary changes in the genome of extant primates (including humans) may shed light not only on the evolutionary history of our species, but also on the mechanisms that underlie common metabolic diseases in modern human populations. In this review, we provide a brief overview of the major dietary shifts that occurred during hominin evolution, and we discuss the methods and approaches used to identify signals of natural selection in patterns of sequence variation. We then review the results of studies aimed at detecting the genetic loci that played a major role in dietary adaptations and conclude by outlining the potential of future studies in this area.
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Affiliation(s)
- F. Luca
- Department of Human Genetics, University of Chicago, Chicago, Illinois 60637
| | - G.H. Perry
- Department of Human Genetics, University of Chicago, Chicago, Illinois 60637
| | - A. Di Rienzo
- Department of Human Genetics, University of Chicago, Chicago, Illinois 60637
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14
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Global features of neural activity in the olfactory system form a parallel code that predicts olfactory behavior and perception. J Neurosci 2010; 30:9017-26. [PMID: 20610736 DOI: 10.1523/jneurosci.0398-10.2010] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Odor identity is coded in spatiotemporal patterns of neural activity in the olfactory bulb. Here we asked whether meaningful olfactory information could also be read from the global olfactory neural population response. We applied standard statistical methods of dimensionality-reduction to neural activity from 12 previously published studies using seven different species. Four studies reported olfactory receptor activity, seven reported glomerulus activity, and one reported the activity of projection-neurons. We found two linear axes of neural population activity that accounted for more than half of the variance in neural response across species. The first axis was correlated with the total sum of odor-induced neural activity, and reflected the behavior of approach or withdrawal in animals, and odorant pleasantness in humans. The second and orthogonal axis reflected odorant toxicity across species. We conclude that in parallel with spatiotemporal pattern coding, the olfactory system can use simple global computations to read vital olfactory information from the neural population response.
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15
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Itsara A, Cooper GM, Baker C, Girirajan S, Li J, Absher D, Krauss RM, Myers RM, Ridker PM, Chasman DI, Mefford H, Ying P, Nickerson DA, Eichler EE. Population analysis of large copy number variants and hotspots of human genetic disease. Am J Hum Genet 2009; 84:148-61. [PMID: 19166990 DOI: 10.1016/j.ajhg.2008.12.014] [Citation(s) in RCA: 459] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 12/16/2008] [Accepted: 12/25/2008] [Indexed: 12/17/2022] Open
Abstract
Copy number variants (CNVs) contribute to human genetic and phenotypic diversity. However, the distribution of larger CNVs in the general population remains largely unexplored. We identify large variants in approximately 2500 individuals by using Illumina SNP data, with an emphasis on "hotspots" prone to recurrent mutations. We find variants larger than 500 kb in 5%-10% of individuals and variants greater than 1 Mb in 1%-2%. In contrast to previous studies, we find limited evidence for stratification of CNVs in geographically distinct human populations. Importantly, our sample size permits a robust distinction between truly rare and polymorphic but low-frequency copy number variation. We find that a significant fraction of individual CNVs larger than 100 kb are rare and that both gene density and size are strongly anticorrelated with allele frequency. Thus, although large CNVs commonly exist in normal individuals, which suggests that size alone can not be used as a predictor of pathogenicity, such variation is generally deleterious. Considering these observations, we combine our data with published CNVs from more than 12,000 individuals contrasting control and neurological disease collections. This analysis identifies known disease loci and highlights additional CNVs (e.g., 3q29, 16p12, and 15q25.2) for further investigation. This study provides one of the first analyses of large, rare (0.1%-1%) CNVs in the general population, with insights relevant to future analyses of genetic disease.
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16
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Mok BW, Ribacke U, Sherwood E, Wahlgren M. A highly conserved segmental duplication in the subtelomeres of Plasmodium falciparum chromosomes varies in copy number. Malar J 2008; 7:46. [PMID: 18325124 PMCID: PMC2279139 DOI: 10.1186/1475-2875-7-46] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2007] [Accepted: 03/07/2008] [Indexed: 11/30/2022] Open
Abstract
Background Segmental duplications (SD) have been found in genomes of various organisms, often accumulated at the ends of chromosomes. It has been assumed that the sequence homology in-between the SDs allow for ectopic interactions that may contribute to the emergence of new genes or gene variants through recombinatorial events. Methods In silico analysis of the 3D7 Plasmodium falciparum genome, conducted to investigate the subtelomeric compartments, led to the identification of subtelomeric SDs. Sequence variation and copy number polymorphisms of the SDs were studied by DNA sequencing, real-time quantitative PCR (qPCR) and fluorescent in situ hybridization (FISH). The levels of transcription and the developmental expression of copy number variant genes were investigated by qPCR. Results A block of six genes of >10 kilobases in size, including var, rif, pfmc-2tm and three hypothetical genes (n-, o- and q-gene), was found duplicated in the subtelomeric regions of chromosomes 1, 2, 3, 6, 7, 10 and 11 (SD1). The number of SD1 per genome was found to vary from 4 to 8 copies in between different parasites. The intragenic regions of SD1 were found to be highly conserved across ten distinct fresh and long-term cultivated P. falciparum. Sequence variation was detected in a ≈ 23 amino-acid long hypervariable region of a surface-exposed loop of PFMC-2TM. A hypothetical gene within SD1, the n-gene, encoding a PEXEL/VTS-containing two-transmembrane protein was found expressed in ring stage parasites. The n-gene transcription levels were found to correlate to the number of n-gene copies. Fragments of SD1 harbouring two or three of the SD1-genes (o-gene, pfmc-2tm, q-gene) were also found in the 3D7 genome. In addition a related second SD, SD2, of ≈ 55% sequence identity to SD1 was found duplicated in a fresh clinical isolate but was only present in a single copy in 3D7 and in other P. falciparum lines or clones. Conclusion Plasmodium falciparum carries multiple sequence conserved SDs in the otherwise highly variable subtelomeres of its chromosomes. The uniqueness of the SDs amongst plasmodium species, and the conserved nature of the genes within, is intriguing and suggests an important role of the SD to P. falciparum.
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Affiliation(s)
- Bobo W Mok
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, SE-171 77 Stockholm, Sweden.
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17
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Abstract
The olfactory system meets niche- and species-specific demands by an accelerated evolution of its odorant receptor repertoires. In this review, we describe evolutionary processes that have shaped olfactory and vomeronasal receptor gene families in vertebrate genomes. We emphasize three important periods in the evolution of the olfactory system evident by comparative genomics: the adaptation to land in amphibian ancestors, the decline of olfaction in primates, and the delineation of putative pheromone receptors concurrent with rodent speciation. The rapid evolution of odorant receptor genes, the sheer size of the repertoire, as well as their wide distribution in the genome, presents a developmental challenge: how are these ever-changing odorant receptor repertoires coordinated within the olfactory system? A central organizing principle in olfaction is the specialization of sensory neurons resulting from each sensory neuron expressing only ~one odorant receptor allele. In this review, we also discuss this mutually exclusive expression of odorant receptor genes. We have considered several models to account for co-regulation of odorant receptor repertoires, as well as discussed a new hypothesis that invokes important epigenetic properties of the system.
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Affiliation(s)
- Marijo B Kambere
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, USA
| | - Robert P Lane
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT, USA
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18
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Rossi M, Ricci E, Colantoni L, Galluzzi G, Frusciante R, Tonali PA, Felicetti L. The Facioscapulohumeral muscular dystrophy region on 4qter and the homologous locus on 10qter evolved independently under different evolutionary pressure. BMC MEDICAL GENETICS 2007; 8:8. [PMID: 17335567 PMCID: PMC1821008 DOI: 10.1186/1471-2350-8-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Accepted: 03/02/2007] [Indexed: 01/23/2023]
Abstract
Background The homologous 4q and 10q subtelomeric regions include two distinctive polymorphic arrays of 3.3 kb repeats, named D4Z4. An additional BlnI restriction site on the 10q-type sequence allows to distinguish the chromosomal origin of the repeats. Reduction in the number of D4Z4 repeats below a threshold of 10 at the 4q locus is tightly linked to Facioscapulohumeral Muscular Dystrophy (FSHD), while similar contractions at 10q locus, are not pathogenic. Sequence variations due to the presence of BlnI-sensitive repeats (10q-type) on chromosome 4 or viceversa of BlnI-resistant repeats (4q-type) on chromosome 10 are observed in both alleles. Results We analysed DNA samples from 116 healthy subiects and 114 FSHD patients and determined the size distributions of polymorphic 4q and 10q alleles, the frequency and the D4Z4 repeat assortment of variant alleles, and finally the telomeric sequences both in standard and variant alleles. We observed the same frequency and types of variant alleles in FSHD patients and controls, but we found marked differences between the repeat arrays of the 4q and 10q chromosomes. In particular we detected 10q alleles completely replaced by the 4q subtelomeric region, consisting in the whole set of 4q-type repeats and the distal telomeric markers. However the reciprocal event, 10q-type subtelomeric region on chromosome 4, was never observed. At 4q locus we always identified hybrid alleles containing a mixture of 4q and 10q-type repeats. Conclusion The different size distribution and different structure of 10q variant alleles as compared with 4q suggests that these loci evolved in a different manner, since the 4q locus is linked to FSHD, while no inheritable disease is associated with mutations in 10qter genomic region. Hybrid alleles on chromosome 4 always retain a minimum number of 4q type repeats, as they are probably essential for maintaining the structural and functional properties of this subtelomeric region. In addition we found: i) several instances of variant alleles that could be misinterpreted and interfere with a correct diagnosis of FSHD; ii) the presence of borderline alleles in the range of 30–40 kb that carried a qA type telomere and were not associated with the disease.
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Affiliation(s)
- Monica Rossi
- Department of Neuroscience, Institute of Neurology, Catholic University of Sacred Heart, L.go A. Gemelli 8, 00168 Rome, Italy
- Fondazione Don Carlo Gnocchi, Via Maresciallo Caviglia, 30, 00194 Rome, Italy
| | - Enzo Ricci
- Department of Neuroscience, Institute of Neurology, Catholic University of Sacred Heart, L.go A. Gemelli 8, 00168 Rome, Italy
- Center for Neuromuscular Diseases, UILDM, Via Prospero Santacroce, 5, 00167 Rome, Italy
| | - Luca Colantoni
- Center for Neuromuscular Diseases, UILDM, Via Prospero Santacroce, 5, 00167 Rome, Italy
| | - Giuliana Galluzzi
- Center for Neuromuscular Diseases, UILDM, Via Prospero Santacroce, 5, 00167 Rome, Italy
| | - Roberto Frusciante
- Department of Neuroscience, Institute of Neurology, Catholic University of Sacred Heart, L.go A. Gemelli 8, 00168 Rome, Italy
| | - Pietro A Tonali
- Department of Neuroscience, Institute of Neurology, Catholic University of Sacred Heart, L.go A. Gemelli 8, 00168 Rome, Italy
- Fondazione Don Carlo Gnocchi, Via Maresciallo Caviglia, 30, 00194 Rome, Italy
| | - Luciano Felicetti
- Department of Neuroscience, Institute of Neurology, Catholic University of Sacred Heart, L.go A. Gemelli 8, 00168 Rome, Italy
- Fondazione Don Carlo Gnocchi, Via Maresciallo Caviglia, 30, 00194 Rome, Italy
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19
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Mehan MR, Almonte M, Slaten E, Freimer NB, Rao PN, Ophoff RA. Analysis of segmental duplications reveals a distinct pattern of continuation-of-synteny between human and mouse genomes. Hum Genet 2006; 121:93-100. [PMID: 17091282 DOI: 10.1007/s00439-006-0277-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Accepted: 10/05/2006] [Indexed: 11/25/2022]
Abstract
About 5% of the human genome consists of large-scale duplicated segments of almost identical sequences. Segmental duplications (SDs) have been proposed to be involved in non-allelic homologous recombination leading to recurrent genomic variation and disease. It has also been suggested that these SDs are associated with syntenic rearrangements that have shaped the human genome. We have analyzed 14 members of a single family of closely related SDs in the human genome, some of which are associated with common inversion polymorphisms at chromosomes 8p23 and 4p16. Comparative analysis with the mouse genome revealed syntenic inversions for these two human polymorphic loci. In addition, 12 of the 14 SDs, while absent in the mouse genome, occur at the breaks of synteny; suggesting a non-random involvement of these sequences in genome evolution. Furthermore, we observed a syntenic familial relationship between 8 and 12 breakpoint-loci, where broken synteny that ends at one family member resumes at another, even across different chromosomes. Subsequent genome-wide assessment revealed that this relationship, which we named continuation-of-synteny, is not limited to the 8p23 family and occurs 46 times in the human genome with high frequency at specific chromosomes. Our analysis supports a non-random breakage model of genomic evolution with an active involvement of segmental duplications for specific regions of the human genome.
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Affiliation(s)
- Michael R Mehan
- Center for Neurobehavioral Genetics, Neuropsychiatric Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
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20
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Willatt LR, Barber JCK, Clarkson A, Simonic I, Raymond FL, Docherty Z, Ogilvie CM. Novel deletion variants of 9q13–q21.12 and classical euchromatic variants of 9q12/qh involve deletion, duplication and triplication of large tracts of segmentally duplicated pericentromeric euchromatin. Eur J Hum Genet 2006; 15:45-52. [PMID: 16985501 DOI: 10.1038/sj.ejhg.5201720] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Large-scale copy number variation that is cytogenetically visible in normal individuals has been described as euchromatic variation but needs to be distinguished from pathogenic euchromatic deletion or duplication. Here, we report eight patients (three families and two individuals) with interstitial deletions of 9q13-q21.12. Fluorescence in situ hybridisation with a large panel of BACs showed that all the deleted clones were from extensive tracts of segmentally duplicated euchromatin, copies of which map to both the long and short arms of chromosome 9. The variety of reasons for which these patients were ascertained, and the phenotypically normal parents, indicates that this is a novel euchromatic variant with no phenotypic effect. Further, four patients with classical euchromatic variants of 9q12/qh or 9p12 were also shown to have duplications or triplications of this segmentally duplicated material common to both 9p and 9q. The cytogenetic boundaries between the segmentally duplicated regions and flanking unique sequences were mapped to 9p13.1 in the short arm (BAC RP11-402N8 at 38.7 Mb) and to 9q21.12 in the long arm (BAC RP11-88I18 at 70.3 Mb). The BACs identified in this study should in future make it possible to differentiate between clinically significant deletions or duplications and euchromatic variants with no established phenotypic consequences.
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Affiliation(s)
- Lionel R Willatt
- Cytogenetics Laboratory, Medical Genetics Department, Cambridge University Hospital NHS Foundation Trust, Cambridge, UK
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21
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Yue Y, Haaf T. 7E olfactory receptor gene clusters and evolutionary chromosome rearrangements. Cytogenet Genome Res 2006; 112:6-10. [PMID: 16276084 DOI: 10.1159/000087507] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Accepted: 03/01/2005] [Indexed: 11/19/2022] Open
Abstract
Olfactory receptor (OR) genes of the 7E subfamily have been duplicated to multiple regions throughout the human genome. Segmental duplications containing 7E OR genes have been associated with both pathological and evolutionary chromosome rearrangements. Many of these breakpoint regions coincide with breaks of chromosomal synteny in the mouse, rat and/or chicken genomes. Collectively, these data suggest that 7E OR-containing regions represent hot spots of genomic instability.
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Affiliation(s)
- Y Yue
- Institute for Human Genetics, Mainz University School of Medicine, Mainz, Germany
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22
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Barber JCK, Maloney V, Hollox EJ, Stuke-Sontheimer A, du Bois G, Daumiller E, Klein-Vogler U, Dufke A, Armour JAL, Liehr T. Duplications and copy number variants of 8p23.1 are cytogenetically indistinguishable but distinct at the molecular level. Eur J Hum Genet 2005; 13:1131-6. [PMID: 16077733 DOI: 10.1038/sj.ejhg.5201475] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
It has been proposed that duplications of 8p23.1 are either euchromatic variants of the 8p23.1 defensin domain with no phenotypic consequences or true duplications associated with developmental delay and heart defects. Here, we provide evidence for both alternatives in two new families. A duplication of most of band 8p23.1 (circa 5 Mb) was found in a girl of 8 years with pulmonary stenosis and mild language delay. BAC fluorescence in situ hybridisation (FISH) and multiplex amplifiable probe hybridisation (MAPH) showed that the two copies of the duplicated segment were sited, in an alternating fashion, between three copies of a circa 300-450 kb segment from 8p23.1 distal to REPD. Copy number of the variable 8p23.1 defensin domain was consistent with duplication but within the normal range. Duplication of the GATA-binding protein 4 gene (GATA4) in this patient and others with and without heart defects, suggests it is a dosage-sensitive gene with variable penetrance. A cytogenetically similar duplication of 8p23.1 was found at prenatal diagnosis in a fetus, father and grandmother. There was no duplication using BAC FISH but MAPH showed 11 copies of the 360 kb variable defensin domain which is within the expanded range found in previous euchromatic variant carriers. Semiquantitative FISH (SQ-FISH) was consistent with a simultaneous expansion of the adjacent olfactory receptor repeats. These results distinguish duplications of 8p23.1 with clinically significant consequences from benign copy number variants, which have not yet been associated with qualitative or quantitative traits.
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Affiliation(s)
- John C K Barber
- Wessex Regional Genetics Laboratory, Salisbury Hospital NHS Trust, Salisbury, Wiltshire, UK.
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23
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Satoh G. Characterization of novel GPCR gene coding locus in amphioxus genome: gene structure, expression, and phylogenetic analysis with implications for its involvement in chemoreception. Genesis 2005; 41:47-57. [PMID: 15682401 DOI: 10.1002/gene.20082] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Chemosensation is the primary sensory modality in almost all metazoans. The vertebrate olfactory receptor genes exist as tandem clusters in the genome, so that identifying their evolutionary origin would be useful for understanding the expansion of the sensory world in relation to a large-scale genomic duplication event in a lineage leading to the vertebrates. In this study, I characterized a novel GPCR (G-protein-coupled receptor) gene-coding locus from the amphioxus genome. The genomic DNA contains an intronless ORF whose deduced amino acid sequence encodes a seven-transmembrane protein with some amino acid residues characteristic of vertebrate olfactory receptors (ORs). Surveying counterparts in the Ciona intestinalis (Asidiacea, Urochordata) genome by querying BLAST programs against the Ciona genomic DNA sequence database resulted in the identification of a remotely related gene. In situ hybridization analysis labeled primary sensory neurons in the rostral epithelium of amphioxus adults. Based on these findings, together with comparison of the developmental gene expression between amphioxus and vertebrates, I postulate that chemoreceptive primary sensory neurons in the rostrum are an ancient cell population traceable at least as far back in phylogeny as the common ancestor of amphioxus and vertebrates.
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Affiliation(s)
- Gouki Satoh
- Department of Zoology, Graduate School of Science, Kyoto University, Kyoto, Japan.
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24
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Abstract
Current models for the evolution of new gene functions after gene duplication presume that the duplication events themselves have no effect on fitness. But those duplications that result in new gene functions are likely to be positively selected from their inception. The evolution of new function may start with the amplification of an existing gene with some level of preadaptation for that function, followed by a period of competitive evolution among the gene copies, resulting in the preservation of the most effective variant and the 'pseudogenization' and eventual loss of the rest.
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Affiliation(s)
- M Pilar Francino
- Evolutionary Genomics Department, DOE Joint Genome Institute and Genomics Division, Lawrence Berkeley National Laboratory, 2800 Mitchell Dr, Walnut Creek, California, USA.
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25
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Gilad Y, Man O, Glusman G. A comparison of the human and chimpanzee olfactory receptor gene repertoires. Genome Res 2005; 15:224-30. [PMID: 15687286 PMCID: PMC546523 DOI: 10.1101/gr.2846405] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Olfactory receptor (OR) genes constitute the basis of the sense of smell and are encoded by the largest mammalian gene superfamily, with >1000 members. In humans, but not in mice or dogs, the majority of OR genes have become pseudogenes, suggesting that OR genes in humans evolve under different selection pressures than in other mammals. To explore this further, we compare the OR gene repertoire of human with its closest living evolutionary relative, by taking advantage of the recently sequenced genome of the chimpanzee. In agreement with previous reports based on a small number of ORs, we find that humans have a significantly higher proportion of OR pseudogenes than chimpanzees. Moreover, we can reject the possibility that humans have been accumulating OR pseudogenes at a constant neutral rate since the divergence of human and chimpanzee. The comparison of the two repertoires reveals two chimpanzee-specific OR subfamily expansions and three expansions specific to humans. It also suggests that a subset of OR genes are under positive selection in either the human or the chimpanzee lineage. Thus, although overall there is relaxed constraint on human olfaction relative to chimpanzee, species-specific sensory requirements appear to have shaped the evolution of the functional OR gene repertoires in both species.
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Affiliation(s)
- Yoav Gilad
- Yale University School of Medicine, Department of Genetics, New Haven, Connecticut 06520, USA.
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26
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Bailey JA, Eichler EE. Genome-wide detection and analysis of recent segmental duplications within mammalian organisms. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2004; 68:115-24. [PMID: 15338609 DOI: 10.1101/sqb.2003.68.115] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- J A Bailey
- Department of Genetics, Center for Computational Genomics, Case Western Reserve University School of Medicine and University Hospitals of Cleveland, Cleveland, Ohio 44106, USA
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27
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Liu X, Li X, Li M, Acimovic YJ, Li Z, Scherer SW, Estivill X, Tsui LC. Characterization of the segmental duplication LCR7-20 in the human genome. Genomics 2004; 83:262-9. [PMID: 14706455 DOI: 10.1016/j.ygeno.2003.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Our previous study described the amplification of a genomic sequence containing exon 9 of CFTR in the human genome. Here we report that this CFTR sequence is part of a large duplicated sequence unit, provisionally named LCR7-20. Through successive screening of two human chromosome 7-specific cosmid libraries to construct a cosmid contig, we assembled two sequenced BAC clones into a single contig containing a prototypic LCR7-20 unit. Subsequent searches of existing human genome sequences identified additional six copies of LCR7-20-like sequences with more than 90% sequence homology. Additional genomic clones containing LCR7-20-like sequences were then isolated from total genomic BAC and PAC libraries. Restriction fragment analysis and limited sequencing data indicated that there could be around 30 copies of LCR7-20-like sequences in the human genome and that the average region of homology could extend over 120 kb. As indicated by fluorescence in situ hybridization analysis, LCR7-20-like sequences are dispersed on different chromosomes, mainly in the centromeric and pericentromeric regions, and some may exist in tandem copies. Our study also indicates that many genomic regions containing LCR7-20's either have been misassembled or are missing in current versions of the human genome sequence.
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Affiliation(s)
- Xiangdong Liu
- The Centre for Applied Genomics, Research Institute, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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28
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Richard F, Lombard M, Dutrillaux B. Reconstruction of the ancestral karyotype of eutherian mammals. Chromosome Res 2004; 11:605-18. [PMID: 14516069 DOI: 10.1023/a:1024957002755] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Applying the parsimony principle, i.e. that chromosomes identical in species belonging to different taxa were likely to be present in their common ancestor, the ancestral karyotype of eutherian mammals (about 100 million years old) was tentatively reconstructed. Comparing chromosome banding with all ZOO-FISH data from literature or studied by us, this reconstruction can be proposed with only limited uncertainties. This karyotype comprised 50 chromosomes of which 40-42 were acrocentrics. Ten ancestral pairs of chromosomes were homologous to a single human chromosome: 5, 6, 9, 11, 13, 17, 18, 20, X and Y (human nomenclature). Nine others were homologous to a part of a human chromosome: 1p + q (proximal), 1q, 2p + q (proximal), 2q, part of 7, 8q, 10p, 10q and 19p (human nomenclature). Finally, seven pairs of chromosomes, homologs to human chromosomes 3 + 21, 4 + 8p, part of 7 + 16p, part of 12 + part of 22 (twice), 14 + 15, 16q + 19q, formed syntenies disrupted in man.
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Affiliation(s)
- F Richard
- UMR 147 CNRS, Institut Curie, Section Recherche, 26 rue d'Ulm, 75248 Paris Cedex 05, France.
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29
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Abstract
Humans perceive an immense variety of chemicals as having distinct odors. Odor perception initiates in the nose, where odorants are detected by a large family of olfactory receptors (ORs). ORs have diverse protein sequences but can be assigned to subfamilies on the basis of sequence relationships. Members of the same subfamily have related sequences and are likely to recognize structurally related odorants. To gain insight into the mechanisms underlying odor perception, we analyzed the human OR gene family. By searching the human genome database, we identified 339 intact OR genes and 297 OR pseudogenes. Determination of their genomic locations showed that OR genes are unevenly distributed among 51 different loci on 21 human chromosomes. Sequence comparisons showed that the human OR family is composed of 172 subfamilies. Types of odorant structures that may be recognized by some subfamilies were predicted by identifying subfamilies that contain ORs with known odor ligands or human homologs of such ORs. Analysis of the chromosomal locations of members of each OR subfamily revealed that most subfamilies are encoded by a single chromosomal locus. Moreover, many loci encode only one or a few subfamilies, suggesting that different parts of the genome may, to some extent, be involved in the detection of different types of odorant structural motifs.
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Affiliation(s)
- Bettina Malnic
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
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30
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Gilad Y, Wiebe V, Przeworski M, Lancet D, Pääbo S. Loss of olfactory receptor genes coincides with the acquisition of full trichromatic vision in primates. PLoS Biol 2004; 2:E5. [PMID: 14737185 PMCID: PMC314465 DOI: 10.1371/journal.pbio.0020005] [Citation(s) in RCA: 266] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2003] [Accepted: 10/28/2003] [Indexed: 11/18/2022] Open
Abstract
Olfactory receptor (OR) genes constitute the molecular basis for the sense of smell and are encoded by the largest gene family in mammalian genomes. Previous studies suggested that the proportion of pseudogenes in the OR gene family is significantly larger in humans than in other apes and significantly larger in apes than in the mouse. To investigate the process of degeneration of the olfactory repertoire in primates, we estimated the proportion of OR pseudogenes in 19 primate species by surveying randomly chosen subsets of 100 OR genes from each species. We find that apes, Old World monkeys and one New World monkey, the howler monkey, have a significantly higher proportion of OR pseudogenes than do other New World monkeys or the lemur (a prosimian). Strikingly, the howler monkey is also the only New World monkey to possess full trichromatic vision, along with Old World monkeys and apes. Our findings suggest that the deterioration of the olfactory repertoire occurred concomitant with the acquisition of full trichromatic color vision in primates. Examination of olfactory receptor genes in 19 primate species suggests that the olfactory repertoire lost complexity as our ancestors acquired full-color vision
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Affiliation(s)
- Yoav Gilad
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
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31
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Amadou C, Younger RM, Sims S, Matthews LH, Rogers J, Kumanovics A, Ziegler A, Beck S, Lindahl KF. Co-duplication of olfactory receptor and MHC class I genes in the mouse major histocompatibility complex. Hum Mol Genet 2003; 12:3025-40. [PMID: 14506126 DOI: 10.1093/hmg/ddg317] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report the 897 kb sequence of a cluster of olfactory receptor (OR) genes located at the distal end of the major histocompatibility complex (MHC) class I region on mouse chromosome 17 of strain 129/SvJ (H2bc). With additional information from the mouse genome draft sequence, we identified 59 OR loci (approximately 20% pseudogenes) in contrast to only 25 OR loci (approximately 50% pseudogenes) in the corresponding centromeric OR cluster that is part of the 'extended MHC class I region' on human chromosome 6. Comparative analysis leads to three major observations: (i) most of the OR subfamilies have evolved independently in the two species, expanding more in the mouse, and resulting in co-orthologs--subfamilies of highly similar paralogs that keep orthologous relationships with their human counterparts; (ii) three of the mouse OR subfamilies have no orthologs in humans; and (iii) MHC class I loci are interspersed in the OR cluster in mouse but not in human, and were subjected to co-duplication with OR genes. Screening of our sequence against the available sequences of other strains/haplotypes revealed that most of the OR loci are polymorphic and that the number of OR loci may vary among strains/haplotypes. Our findings that MHC-linked OR loci share duplication with MHC class I loci, have duplicated extensively and are polymorphic revives questions about potential reciprocal influences acting on the dynamics and evolution of the H2 region and the H2-linked OR loci.
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MESH Headings
- Alleles
- Amino Acid Sequence
- Animals
- Chromosome Mapping
- Chromosomes, Human, Pair 6
- Chromosomes, Mammalian
- Consensus Sequence
- Evolution, Molecular
- Gene Duplication
- Genes, MHC Class I
- Haplotypes
- Histocompatibility Antigens Class II/genetics
- Humans
- Major Histocompatibility Complex/genetics
- Mice
- Mice, Inbred Strains
- Molecular Sequence Data
- Mutation
- Phylogeny
- Polymorphism, Genetic
- Protein Structure, Tertiary
- Receptors, Odorant/chemistry
- Receptors, Odorant/genetics
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Species Specificity
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Affiliation(s)
- Claire Amadou
- Howard Hughes Medical Institute and Center for Immunology, University of Texas Southwestern Medical Center, Dallas, 75390-9050, USA
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32
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Abstract
Since many gene duplications in the human genome are ancient duplications going back to the origin of vertebrates, the question may be asked about the fate of such duplicated genes at the compositional genome transitions that occurred between cold- and warm-blooded vertebrates. Indeed, at that transition, about half of the (GC-poor) genes of cold-blooded vertebrates (the genes of the gene-dense "ancestral genome core") underwent a GC enrichment to become the genes of the "genome core" of warm-blooded vertebrates. Since the compositional distribution of the human duplicated genes investigated (1111 pairs) mimics the general distribution of human genes (about 50% GC(3)-poor and 50% GC(3)-rich genes, the border being at 60% GC(3)), we considered two possibilities, namely that the compositional transition affected either (i) about half of the copies on a random basis, or (ii) preferentially only one copy of the duplicated genes. The two possibilities could be distinguished if each copy is put into one of two subsets according to its GC(3) level. Indeed, in the first case, the two distributions would be similar, whereas in the second case, the two distributions would be different, one copy having maintained the ancestral GC-poor composition, and one copy having undergone the compositional change. Using this approach, we could show that, by far and large, one copy of the duplicated genes preferentially underwent the GC enrichment. This result implies that this copy, which had possibly acquired a different function and/or regulation, was preferentially translocated into the gene-dense compartment of the genome, the "ancestral genome core", namely the "gene space" which underwent the compositional transition at the emergence of warm-blooded vertebrates.
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Affiliation(s)
- Kamel Jabbari
- Laboratoire de Génétique Moléculaire, Institut Jacques Monod, 2 Place Jussieu, F-75005 Paris, France
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33
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Gilad Y, Bustamante CD, Lancet D, Pääbo S. Natural selection on the olfactory receptor gene family in humans and chimpanzees. Am J Hum Genet 2003; 73:489-501. [PMID: 12908129 PMCID: PMC1180675 DOI: 10.1086/378132] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2003] [Accepted: 06/10/2003] [Indexed: 11/03/2022] Open
Abstract
The olfactory receptor (OR) genes constitute the largest gene family in mammalian genomes. Humans have >1,000 OR genes, of which only approximately 40% have an intact coding region and are therefore putatively functional. In contrast, the fraction of intact OR genes in the genomes of the great apes is significantly greater (68%-72%), suggesting that selective pressures on the OR repertoire vary among these species. We have examined the evolutionary forces that shaped the OR gene family in humans and chimpanzees by resequencing 20 OR genes in 16 humans, 16 chimpanzees, and one orangutan. We compared the variation at the OR genes with that at intergenic regions. In both humans and chimpanzees, OR pseudogenes seem to evolve neutrally. In chimpanzees, patterns of variability are consistent with purifying selection acting on intact OR genes, whereas, in humans, there is suggestive evidence for positive selection acting on intact OR genes. These observations are likely due to differences in lifestyle, between humans and great apes, that have led to distinct sensory needs.
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Affiliation(s)
- Yoav Gilad
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
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34
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Sugawara H, Harada N, Ida T, Ishida T, Ledbetter DH, Yoshiura KI, Ohta T, Kishino T, Niikawa N, Matsumoto N. Complex low-copy repeats associated with a common polymorphic inversion at human chromosome 8p23. Genomics 2003; 82:238-44. [PMID: 12837273 DOI: 10.1016/s0888-7543(03)00108-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To characterize a submicroscopic, common 8p23 polymorphic inversion, we constructed a complete BAC/PAC-based physical map covering the entire 4.7-Mb inversion and its flanking regions. Two low-copy repeats (LCRs), REPD (approximately 1.3 Mb) and REPP (approximately 0.4 Mb), were identified at each of the inversion breakpoints. Comparison of the REPD and REPP sequences revealed that REPD showed high homology to REPP, with complex direct and inverted orientations. REPD and REPP contain six and five olfactory receptor gene-related sequences, respectively. LCRs at 8p23 showed multiple FISH signals from an Old World monkey to the human. Thus, multiplication of the LCR may have occurred at least 21-25 million years ago. We also investigated the frequency of the 4.7-Mb inversion in the general Japanese population and found that the allele frequency for the 8p23 inversion was estimated to be 27%.
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Affiliation(s)
- Hirobumi Sugawara
- Department of Human Genetics, Nagasaki University Graduate School of Biomedical Sciences, Sakamoto 1-12-4, Nagasaki 852-8523, Japan
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35
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Golfier G, Chibon F, Aurias A, Chen XN, Korenberg J, Rossier J, Potier MC. The 200-kb segmental duplication on human chromosome 21 originates from a pericentromeric dissemination involving human chromosomes 2, 18 and 13. Gene 2003; 312:51-9. [PMID: 12909340 DOI: 10.1016/s0378-1119(03)00673-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Regions close to human centromeres contain DNA fragments spanning hundreds of kilobases that exhibit a high degree of sequence identity (>95%). Here we report the genomic structure and evolution of a family of four paralogous regions related to a 220-kb genomic fragment present on the long arm of human chromosome 21 (21q22.1). Phylogenetic classification of the paralogous sequences obtained from the draft of the Human Genome Project are in agreement with results from comparative fluorescence in situ hybridization on metaphase chromosomes from human and great apes. The original copy present in 21q22.1 in human was duplicated in great apes after the divergence of the orang-utan and inserted in a pericentromeric region, most likely the ancestor of HSA2q, then disseminated by transposition of a larger fragment to other pericentromeric locations: HSA18p11, HSA13q11 and HSA21q11.1. The degree of dissemination varies among species.
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MESH Headings
- Animals
- Chromosome Aberrations
- Chromosomes, Human, Pair 13/genetics
- Chromosomes, Human, Pair 18/genetics
- Chromosomes, Human, Pair 2/genetics
- Chromosomes, Human, Pair 21/genetics
- Gene Duplication
- Genome, Human
- Humans
- In Situ Hybridization, Fluorescence
- Pan paniscus/genetics
- Phylogeny
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Affiliation(s)
- Geoffroy Golfier
- Neurobiologie et Diversité Cellulaire, CNRS UMR7637, Ecole Supérieure de Physique et Chimie Industrielles, 10 rue Vauquelin, 75005 Paris, France
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36
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Abstract
Groups of related genes abound in large eukaryotic genomes. In such 'subgenomes', homology modeling carried out for a few genes will probably have relevance to the entire group. Subgenomes also afford unique ways of determining protein structural information. In addition to analyses based on the quantification of residue variability in paralogs, two-way comparisons, both within and among species, help to disclose functional amino acids. Comparative studies of gene families throughout the mammalian genome will also help elucidate the functional significance of single nucleotide polymorphisms in coding regions.
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Affiliation(s)
- Orna Man
- The Crown Human Genome Center, The Weizmann Institute of Science, Rehovot, 76100, Israel
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37
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Abstract
Large segmental duplications (SDs) constitute at least 3.6% of the human genome and have increased its size, complexity, and diversity. SDs can mediate ectopic sequence exchange resulting in gross chromosomal rearrangements that could contribute to speciation and disease. We have identified and evaluated a subset of human SDs that harbor an 88-member subfamily of olfactory receptor (OR)-like genes called the 7Es. At least 92% of these genes appear to be pseudogenes when compared to other OR genes. The 7E-containing SDs (7E SDs) have duplicated to at least 35 regions of the genome via intra- and interchromosomal duplication events. In contrast to many human SDs, the 7E SDs are not biased towards pericentromeric or subtelomeric regions. We find evidence for gene conversion among 7E genes and larger sequence exchange between 7E SDs, supporting the hypothesis that long, highly similar stretches of DNA facilitate ectopic interactions. The complex structure and history of the 7E SDs necessitates extension of the current model of large-scale DNA duplication. Despite their appearance as pseudogenes, some 7E genes exhibit a signature of purifying selection, and at least one 7E gene is expressed.
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Affiliation(s)
- Tera Newman
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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38
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Locke DP, Segraves R, Carbone L, Archidiacono N, Albertson DG, Pinkel D, Eichler EE. Large-scale variation among human and great ape genomes determined by array comparative genomic hybridization. Genome Res 2003; 13:347-57. [PMID: 12618365 PMCID: PMC430292 DOI: 10.1101/gr.1003303] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Large-scale genomic rearrangements are a major force of evolutionary change and the ascertainment of such events between the human and great ape genomes is fundamental to a complete understanding of the genetic history and evolution of our species. Here, we present the results of an evolutionary analysis utilizing array comparative genomic hybridization (array CGH), measuring copy-number gains and losses among these species. Using an array of 2460 human bacterial artificial chromosomes (BACs) (12% of the genome), we identified a total of 63 sites of putative DNA copy-number variation between humans and the great apes (chimpanzee, bonobo, gorilla, and orangutan). Detailed molecular characterization of a subset of these sites confirmed rearrangements ranging from 40 to at least 175 kb in size. Surprisingly, the majority of variant sites differentiating great ape and human genomes were found within interstitial euchromatin. These data suggest that such large-scale events are not restricted solely to subtelomeric or pericentromeric regions, but also occur within genic regions. In addition, 5/9 of the verified variant sites localized to areas of intrachromosomal segmental duplication within the human genome. On the basis of the frequency of duplication in humans, this represents a 14-fold positional bias. In contrast to previous cytogenetic and comparative mapping studies, these results indicate extensive local repatterning of hominoid chromosomes in euchromatic regions through a duplication-driven mechanism of genome evolution.
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Affiliation(s)
- Devin P Locke
- Department of Genetics, Case Western Reserve University School of Medicine and University Hospitals of Cleveland, Cleveland, Ohio 44106, USA
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39
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Guy J, Hearn T, Crosier M, Mudge J, Viggiano L, Koczan D, Thiesen HJ, Bailey JA, Horvath JE, Eichler EE, Earthrowl ME, Deloukas P, French L, Rogers J, Bentley D, Jackson MS. Genomic sequence and transcriptional profile of the boundary between pericentromeric satellites and genes on human chromosome arm 10p. Genome Res 2003; 13:159-72. [PMID: 12566394 PMCID: PMC420363 DOI: 10.1101/gr.644503] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2002] [Accepted: 11/04/2002] [Indexed: 11/24/2022]
Abstract
Contiguous finished sequence from highly duplicated pericentromeric regions of human chromosomes is needed if we are to understand the role of pericentromeric instability in disease, and in gene and karyotype evolution. Here, we have constructed a BAC contig spanning the transition from pericentromeric satellites to genes on the short arm of human chromosome 10, and used this to generate 1.4 Mb of finished genomic sequence. Combining RT-PCR, in silico gene prediction, and paralogy analysis, we can identify two domains within the sequence. The proximal 600 kb consists of satellite-rich pericentromerically duplicated DNA which is transcript poor, containing only three unspliced transcripts. In contrast, the distal 850 kb contains four known genes (ZNF248, ZNF25, ZNF33A, and ZNF37A) and up to 32 additional transcripts of unknown function. This distal region also contains seven out of the eight intrachromosomal duplications within the sequence, including the p arm copy of the approximately 250-kb duplication which gave rise to ZNF33A and ZNF33B. By sequencing orthologs of the duplicated ZNF33 genes we have established that ZNF33A has diverged significantly at residues critical for DNA binding but ZNF33B has not, indicating that ZNF33B has remained constrained by selection for ancestral gene function. These results provide further evidence of gene formation within intrachromosomal duplications, but indicate that recent interchromosomal duplications at this centromere have involved transcriptionally inert, satellite rich DNA, which is likely to be heterochromatic. This suggests that any novel gene structures formed by these interchromosomal events would require relocation to a more open chromatin environment to be expressed.
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Affiliation(s)
- Jane Guy
- The Institute of Human Genetics, The International Centre for Life, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 3BZ, UK
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40
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Safran M, Chalifa-Caspi V, Shmueli O, Olender T, Lapidot M, Rosen N, Shmoish M, Peter Y, Glusman G, Feldmesser E, Adato A, Peter I, Khen M, Atarot T, Groner Y, Lancet D. Human Gene-Centric Databases at the Weizmann Institute of Science: GeneCards, UDB, CroW 21 and HORDE. Nucleic Acids Res 2003; 31:142-6. [PMID: 12519968 PMCID: PMC165497 DOI: 10.1093/nar/gkg050] [Citation(s) in RCA: 158] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recent enhancements and current research in the GeneCards (GC) (http://bioinfo.weizmann.ac.il/cards/) project are described, including the addition of gene expression profiles and integrated gene locations. Also highlighted are the contributions of specialized associated human gene-centric databases developed at the Weizmann Institute. These include the Unified Database (UDB) (http://bioinfo.weizmann.ac.il/udb) for human genome mapping, the human Chromosome 21 database at the Weizmann Insti-tute (CroW 21) (http://bioinfo.weizmann.ac.il/crow21), and the Human Olfactory Receptor Data Explora-torium (HORDE) (http://bioinfo.weizmann.ac.il/HORDE). The synergistic relationships amongst these efforts have positively impacted the quality, quantity and usefulness of the GeneCards gene compendium.
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Affiliation(s)
- Marilyn Safran
- Department of Biological Services (Bioinformatics Unit), The Weizmann Institute of Science, 76100 Rehovot, Israel.
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41
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Abstract
Genomic rearrangements play a major role in the pathogenesis of human genetic diseases. Nonallelic homologous recombination (NAHR) between low-copy repeats (LCRs) that flank unique genomic segments results in changes of genome organization and can cause a loss or gain of genomic segments. These LCRs appear to have arisen recently during primate speciation via paralogous segmental duplication, thus making the human species particularly susceptible to genomic rearrangements. Genomic disorders are defined as a group of diseases that result from genomic rearrangements, mostly mediated by NAHR. Molecular investigations of genomic disorders have revealed genome architectural features associated with susceptibility to rearrangements and the recombination mechanisms responsible for such rearrangements. The human genome sequence project reveals that LCRs may account for 5% of the genome, suggesting that many novel genomic disorders might still remain to be recognized.
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Affiliation(s)
- Ken Inoue
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.
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42
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Gygi MP, Ferguson MD, Mefford HC, Lund KP, O'Day C, Zhou P, Friedman C, van den Engh G, Stolowitz ML, Trask BJ. Use of fluorescent sequence-specific polyamides to discriminate human chromosomes by microscopy and flow cytometry. Nucleic Acids Res 2002; 30:2790-9. [PMID: 12087162 PMCID: PMC117061 DOI: 10.1093/nar/gkf406] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2002] [Accepted: 04/24/2002] [Indexed: 01/20/2023] Open
Abstract
In this paper, we demonstrate the use of synthetic polyamide probes to fluorescently label heterochromatic regions on human chromosomes for discrimination in cytogenetic preparations and by flow cytometry. Polyamides bind to the minor groove of DNA in a sequence-specific manner. Unlike conventional sequence-specific DNA or RNA probes, polyamides can recognize their target sequence without the need to subject chromosomes to harsh denaturing conditions. For this study, we designed and synthesized a polyamide to target the TTCCA-motif repeated in the heterochromatic regions of chromosome 9, Y and 1. We demonstrate that the fluorescently labeled polyamide binds to its target sequence in both conventional cytogenetic preparations of metaphase chromosomes and suspended chromosomes without denaturation. Chromosomes 9 and Y can be discriminated and purified by flow sorting on the basis of polyamide binding and Hoechst 33258 staining. We generate chromosome 9- and Y-specific 'paints' from the sorted fractions. We demonstrate the utility of this technology by characterizing the sequence of an olfactory receptor gene that is duplicated on multiple chromosomes. By separating chromosome 9 from chromosomes 10-12 on the basis of polyamide fluorescence, we determine and differentiate the haplotypes of the highly similar copies of this gene on chromosomes 9 and 11.
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Affiliation(s)
- Melanie P Gygi
- Department of Molecular Biotechnology, University of Washington, Seattle, WA 98195, USA
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43
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Eason DD, Litman GW. Haplotype exclusion: the unique case presented by multiple immunoglobulin gene loci in cartilaginous fish. Semin Immunol 2002; 14:145-52; discussion 220. [PMID: 12160642 DOI: 10.1016/s1044-5323(02)00038-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cartilaginous fish represent the most phylogenetically distant species from man in which immunoglobulin and T cell antigen receptor genes have been identified. Immunoglobulin genes in cartilaginous fish are organized in hundreds of clusters, located on different chromosomes and presumably are under independent regulation; large numbers of immunoglobulin gene clusters are germline-joined and thus their expression is not directly dependent on somatic rearrangement. Despite the unusual nature of immunoglobulin gene genetics in these species, preliminary characterization of the transcription products of immunoglobulin loci in single cell isolates is consistent with haplotype exclusion. Certain features of immunoglobulin gene organization and expression in cartilaginous fish are remarkably similar to that of odorant receptors and suggest that at the level of transcriptional regulation, at least two different mechanisms could exist that relate to haplotype exclusion.
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Affiliation(s)
- Donna D Eason
- Department of Molecular Genetics, All Children's Hospital, St. Petersburg, FL 33701, USA
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44
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Abstract
The olfactory system sits at the interface of the environment and the nervous system and is responsible for correctly coding sensory information from thousands of odorous stimuli. Many theories existed regarding the signal transduction mechanism that mediates this difficult task. The discovery that odorant transduction utilizes a unique variation (a novel family of G protein-coupled receptors) based upon a very common theme (the G protein-coupled adenylyl cyclase cascade) to accomplish its vital task emphasized the power and versatility of this motif. We now must understand the downstream consequences of this cascade that regulates multiple second messengers and perhaps even gene transcription in response to the initial interaction of ligand with G protein-coupled receptor.
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Affiliation(s)
- Gabriele V Ronnett
- Departments of Neuroscience and Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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45
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Abstract
An increasing number of human diseases are recognized to result from recurrent DNA rearrangements involving unstable genomic regions. These are termed genomic disorders, in which the clinical phenotype is a consequence of abnormal dosage of gene(s) located within the rearranged genomic fragments. Both inter- and intrachromosomal rearrangements are facilitated by the presence of region-specific low-copy repeats (LCRs) and result from nonallelic homologous recombination (NAHR) between paralogous genomic segments. LCRs usually span approximately 10-400 kb of genomic DNA, share >or= 97% sequence identity, and provide the substrates for homologous recombination, thus predisposing the region to rearrangements. Moreover, it has been suggested that higher order genomic architecture involving LCRs plays a significant role in karyotypic evolution accompanying primate speciation.
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Affiliation(s)
- Paweł Stankiewicz
- Dept Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3498, USA
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46
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Abstract
Chemosensory receptors are critical for the survival of many mammalian species, and their genes can comprise up to 1% of mammalian genomes. Odorant, taste, and vomeronasal receptors are being discovered and functionally characterized at a rapid pace which has been further accelerated by the availability of the human genome sequence. Five multigene families, consisting of >1,000 genes in the mouse, have been proposed to encode functional chemoreceptors. Although all of the chemoreceptor gene families encode G-protein coupled receptors, they are largely unrelated and uniquely specialized for the processing of different chemosensory modalities. Using members of the families as molecular probes, great insights are being gained into the different organizational strategies used by these sensory systems to encode information in both the periphery and the brain.
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Affiliation(s)
- Susan L Sullivan
- Section of Molecular Neuroscience, Laboratory of Molecular Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, MD 20850, USA
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47
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Abstract
The nose of Homo sapiens is a sophisticated chemical sensor. It is able to smell almost any type of volatile molecule, often at extraordinarily low concentrations, and can make fine perceptual discriminations between structurally related molecules. The diversity of odor recognition is mediated by odorant receptor (OR) genes, discovered in 1991 by Buck & Axel. OR genes form the largest gene families in mammalian genomes. A decade after their discovery, advances in the sequencing of the human genome have provided a first draft of the human OR repertoire: It consists of approximately 1000 sequences, residing in multiple clusters spread throughout the genome, with more than half being pseudogenes. Allelic variants are beginning to be recognized and may provide an opportunity for genotype-phenotype correlations. Here, I review the current knowledge of the human OR repertoire and summarize the limited information available regarding putative pheromone and taste receptors in humans.
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Affiliation(s)
- P Mombaerts
- The Rockefeller University, New York, New York 10021, USA.
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48
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Crosier M, Viggiano L, Guy J, Misceo D, Stones R, Wei W, Hearn T, Ventura M, Archidiacono N, Rocchi M, Jackson MS. Human paralogs of KIAA0187 were created through independent pericentromeric-directed and chromosome-specific duplication mechanisms. Genome Res 2002; 12:67-80. [PMID: 11779832 PMCID: PMC155266 DOI: 10.1101/gr.213702] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
KIAA0187 is a gene of unknown function that maps to 10q11 and has been subject to recent duplication events. Here we analyze 18 human paralogs of this gene and show that paralogs of exons 14-23 were formed through satellite-associated pericentromeric-directed duplication, whereas paralogs of exons 1-9 were created via chromosome-specific satellite-independent duplications. In silico, Northern, and RT-PCR analyses indicate that nine paralogs are transcribed, including four in which KIAA0187 exons are spliced onto novel sequences. Despite this, no new genes appear to have been created by these events. The chromosome 10 paralogs map to 10q11, 10q22, 10q23.1, and 10q23.3, forming part of a complex family of chromosome-specific repeats that includes GLUD1, Cathepsin L, and KIAA1099 pseudogenes. Phylogenetic analyses and comparative FISH indicates that the 10q23.1 and 10q23.3 repeats were created in 10q11 and relocated by a paracentric inversion 13 to 27 Myr ago. Furthermore, the most recent duplications, involving the KIAA1099 pseudogenes, have largely been confined to 10q11. These results indicate a simple model for the evolution of this repeat family, involving multiple rounds of centromere-proximal duplication and dispersal through intrachromosomal rearrangement. However, more complex events must be invoked to account for high sequence identity between some paralogs.
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Affiliation(s)
- Moira Crosier
- The Institute of Human Genetics, The International Centre for Life, Central Parkway, University of Newcastle Upon Tyne, NE1 3BZ, United Kingdom
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Lane RP, Roach JC, Lee IY, Boysen C, Smit A, Trask BJ, Hood L. Genomic analysis of the olfactory receptor region of the mouse and human T-cell receptor alpha/delta loci. Genome Res 2002; 12:81-7. [PMID: 11779833 PMCID: PMC155264 DOI: 10.1101/gr.197901] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2001] [Accepted: 10/16/2001] [Indexed: 11/24/2022]
Abstract
We have conducted a comparative genomic analysis of several olfactory receptor (OR) genes that lie immediately 5' to the V-alpha gene segments at the mouse and human T-cell receptor (TCR) alpha/delta loci. Five OR genes are identified in the human cluster. The murine cluster has at least six OR genes; the first five are orthologous to the human genes. The sixth mouse gene has arisen since mouse-human divergence by a duplication of a approximately 10-kb block. One pair of OR paralogs found at the mouse and human loci are more similar to each other than to their corresponding orthologs. This paralogous "twinning" appears to be under selection, perhaps to increase sensitivity to particular odorants or to resolve structurally-similar odorants. The promoter regions of the mouse OR genes were identified by RACE-PCR. Orthologs share extensive 5' UTR homology, but we find no significant similarity among paralogs. These findings extend previous observations that suggest that OR genes do not share local significant regulatory homology despite having a common regulatory agenda. We also identified a diverged TCR-alpha gene segment that uses a divergent recombination signal sequence (RSS) to initiate recombination in T-cells from within the OR region. We explored the hypothesis that OR genes may use DNA recombination in expressing neurons, e.g., to recombine ORs into a transcriptionally active locus. We searched the mouse sequence for OR-flanking RSS motifs, but did not find evidence to suggest that these OR genes use TCR-like recombination target sequences.
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Affiliation(s)
- Robert P Lane
- Department of Molecular Biotechnology, University of Washington, Seattle, Washington 98195, USA.
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Bailey JA, Yavor AM, Viggiano L, Misceo D, Horvath JE, Archidiacono N, Schwartz S, Rocchi M, Eichler EE. Human-specific duplication and mosaic transcripts: the recent paralogous structure of chromosome 22. Am J Hum Genet 2002; 70:83-100. [PMID: 11731936 PMCID: PMC419985 DOI: 10.1086/338458] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2001] [Accepted: 10/31/2001] [Indexed: 11/03/2022] Open
Abstract
In recent decades, comparative chromosomal banding, chromosome painting, and gene-order studies have shown strong conservation of gross chromosome structure and gene order in mammals. However, findings from the human genome sequence suggest an unprecedented degree of recent (<35 million years ago) segmental duplication. This dynamism of segmental duplications has important implications in disease and evolution. Here we present a chromosome-wide view of the structure and evolution of the most highly homologous duplications (> or = 1 kb and > or = 90%) on chromosome 22. Overall, 10.8% (3.7/33.8 Mb) of chromosome 22 is duplicated, with an average sequence identity of 95.4%. To organize the duplications into tractable units, intron-exon structure and well-defined duplication boundaries were used to define 78 duplicated modules (minimally shared evolutionary segments) with 157 copies on chromosome 22. Analysis of these modules provides evidence for the creation or modification of 11 novel transcripts. Comparative FISH analyses of human, chimpanzee, gorilla, orangutan, and macaque reveal qualitative and quantitative differences in the distribution of these duplications--consistent with their recent origin. Several duplications appear to be human specific, including a approximately 400-kb duplication (99.4%-99.8% sequence identity) that transposed from chromosome 14 to the most proximal pericentromeric region of chromosome 22. Experimental and in silico data further support a pericentromeric gradient of duplications where the most recent duplications transpose adjacent to the centromere. Taken together, these data suggest that segmental duplications have been an ongoing process of primate genome evolution, contributing to recent gene innovation and the dynamic transformation of genome architecture within and among closely related species.
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MESH Headings
- Animals
- Centromere/genetics
- Chromosomes, Human, Pair 14/genetics
- Chromosomes, Human, Pair 22/genetics
- Evolution, Molecular
- Exons/genetics
- Gene Dosage
- Gene Duplication
- Genes, Duplicate/genetics
- Humans
- In Situ Hybridization, Fluorescence
- Introns/genetics
- Mosaicism/genetics
- Primates/genetics
- RNA, Messenger/analysis
- RNA, Messenger/genetics
- Species Specificity
- Time Factors
- Transcription, Genetic/genetics
- Translocation, Genetic/genetics
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Affiliation(s)
- Jeffrey A Bailey
- Department of Genetics and Center for Human Genetics, Case Western Reserve University School of Medicine and University Hospitals of Cleveland, OH, USA
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