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Nandakumar M, Lundberg M, Carlsson F, Råberg L. Balancing selection on the complement system of a wild rodent. BMC Ecol Evol 2023; 23:21. [PMID: 37231383 DOI: 10.1186/s12862-023-02122-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 05/10/2023] [Indexed: 05/27/2023] Open
Abstract
BACKGROUND Selection pressure exerted by pathogens can influence patterns of genetic diversity in the host. In the immune system especially, numerous genes encode proteins involved in antagonistic interactions with pathogens, paving the way for coevolution that results in increased genetic diversity as a consequence of balancing selection. The complement system is a key component of innate immunity. Many complement proteins interact directly with pathogens, either by recognising pathogen molecules for complement activation, or by serving as targets of pathogen immune evasion mechanisms. Complement genes can therefore be expected to be important targets of pathogen-mediated balancing selection, but analyses of such selection on this part of the immune system have been limited. RESULTS Using a population sample of whole-genome resequencing data from wild bank voles (n = 31), we estimated the extent of genetic diversity and tested for signatures of balancing selection in multiple complement genes (n = 44). Complement genes showed higher values of standardised β (a statistic expected to be high under balancing selection) than the genome-wide average of protein coding genes. One complement gene, FCNA, a pattern recognition molecule that interacts directly with pathogens, was found to have a signature of balancing selection, as indicated by the Hudson-Kreitman-Aguadé test (HKA) test. Scans for localised signatures of balancing selection in this gene indicated that the target of balancing selection was found in exonic regions involved in ligand binding. CONCLUSION The present study adds to the growing evidence that balancing selection may be an important evolutionary force on components of the innate immune system. The identified target in the complement system typifies the expectation that balancing selection acts on genes encoding proteins involved in direct interactions with pathogens.
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Affiliation(s)
| | - Max Lundberg
- Department of Biology, Lund University, Lund, Sweden
| | | | - Lars Råberg
- Department of Biology, Lund University, Lund, Sweden
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Croze M, Wollstein A, Božičević V, Živković D, Stephan W, Hutter S. A genome-wide scan for genes under balancing selection in Drosophila melanogaster. BMC Evol Biol 2017; 17:15. [PMID: 28086750 PMCID: PMC5237213 DOI: 10.1186/s12862-016-0857-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 12/17/2016] [Indexed: 04/12/2023] Open
Abstract
BACKGROUND In the history of population genetics balancing selection has been considered as an important evolutionary force, yet until today little is known about its abundance and its effect on patterns of genetic diversity. Several well-known examples of balancing selection have been reported from humans, mice, plants, and parasites. However, only very few systematic studies have been carried out to detect genes under balancing selection. We performed a genome scan in Drosophila melanogaster to find signatures of balancing selection in a derived (European) and an ancestral (African) population. We screened a total of 34 genomes searching for regions of high genetic diversity and an excess of SNPs with intermediate frequency. RESULTS In total, we found 183 candidate genes: 141 in the European population and 45 in the African one, with only three genes shared between both populations. Most differences between both populations were observed on the X chromosome, though this might be partly due to false positives. Functionally, we find an overrepresentation of genes involved in neuronal development and circadian rhythm. Furthermore, some of the top genes we identified are involved in innate immunity. CONCLUSION Our results revealed evidence of genes under balancing selection in European and African populations. More candidate genes have been found in the European population. They are involved in several different functions.
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Affiliation(s)
- Myriam Croze
- Section of Evolutionary Biology, Department of Biology II, University of Munich (LMU), Grosshaderner Str. 2, 82152, Planegg-Martinsried, Germany.
| | - Andreas Wollstein
- Section of Evolutionary Biology, Department of Biology II, University of Munich (LMU), Grosshaderner Str. 2, 82152, Planegg-Martinsried, Germany
| | - Vedran Božičević
- Section of Evolutionary Biology, Department of Biology II, University of Munich (LMU), Grosshaderner Str. 2, 82152, Planegg-Martinsried, Germany
| | - Daniel Živković
- Section of Evolutionary Biology, Department of Biology II, University of Munich (LMU), Grosshaderner Str. 2, 82152, Planegg-Martinsried, Germany.,Center of Food and Life Sciences Weihenstephan, Technische Universität München, 85354, Freising, Germany
| | - Wolfgang Stephan
- Section of Evolutionary Biology, Department of Biology II, University of Munich (LMU), Grosshaderner Str. 2, 82152, Planegg-Martinsried, Germany.,Natural History Museum Berlin, 10115, Berlin, Germany
| | - Stephan Hutter
- Section of Evolutionary Biology, Department of Biology II, University of Munich (LMU), Grosshaderner Str. 2, 82152, Planegg-Martinsried, Germany
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Wang Y, Xu S, Su Y, Ye B, Hua Z. Molecular characterization and expression analysis of complement component C9 gene in the whitespotted bambooshark, Chiloscyllium plagiosum. FISH & SHELLFISH IMMUNOLOGY 2013; 35:599-606. [PMID: 23684808 DOI: 10.1016/j.fsi.2013.04.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 04/10/2013] [Accepted: 04/29/2013] [Indexed: 06/02/2023]
Abstract
Complement system is known as highly sophisticated immune defense mechanism for antigen recognition as well as effector functions. Activation of the terminal pathway of the complement system leads to the assembly of terminal complement complexes (C5b-9), which induces the characteristic complement-mediated cytolysis. The lytic activity of shark complement involves functional analogues of mammalian C8 and C9. In this article, a full-length cDNA of C9 (CpC9) is identified from cartilaginous species, the whitespotted bambooshark, Chiloscyllium plagiosum by RACE. The CpC9 cDNA is 2263 bp in length, encoding a protein of 603 amino acids, which shares 42% and 43% identity with human and Xenopus C9 respectively. Through sequence alignment and comparative analysis, the CpC9 protein was found well conserved, with the typical modular architecture in TCCs and nearly unanimous cysteine composition from fish to mammal. Phylogenetic analysis places it in a clade with C9 orthologs in higher vertebrate and as a sister taxa to the Xenopus. Expression analysis revealed that CpC9 is constitutively highly expressed in shark liver, with much less or even undetectable expression in other tissues; demonstrating liver is the primary tissue for C9synthesis. To sum up, the structural conservation and distinctive phylogenetics might indicate the potentially vital role of CpC9 in shark immune response, though it remains to be confirmed by further study.
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Affiliation(s)
- Ying Wang
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, No. 22 Hankou Rd, Gulou District, Nanjing 210093, PR China
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Sun C, Huo D, Southard C, Nemesure B, Hennis A, Cristina Leske M, Wu SY, Witonsky DB, Olopade OI, Di Rienzo A. A signature of balancing selection in the region upstream to the human UGT2B4 gene and implications for breast cancer risk. Hum Genet 2011; 130:767-75. [PMID: 21660508 PMCID: PMC4478588 DOI: 10.1007/s00439-011-1025-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 05/28/2011] [Indexed: 10/18/2022]
Abstract
UDP-glucuronosyltransferase 2 family, polypeptide B4 (UGT2B4) is an important metabolizing enzyme involved in the clearance of many xenobiotics and endogenous substrates, especially steroid hormones and bile acids. The HapMap data show that numerous SNPs upstream of UGT2B4 are in near-perfect linkage disequilibrium with each other and occur at intermediate frequency, indicating that this region might contain a target of natural selection. To investigate this possibility, we chose three regions (4.8 kb in total) for resequencing and observed a striking excess of intermediate-frequency alleles that define two major haplotypes separated by many mutation events and with little differentiation across populations, thus suggesting that the variation pattern upstream UGT2B4 is highly unusual and may be the result of balancing selection. We propose that this pattern is due to the maintenance of a regulatory polymorphism involved in the fine tuning of UGT2B4 expression so that heterozygous genotypes result in optimal enzyme levels. Considering the important role of steroid hormones in breast cancer susceptibility, we hypothesized that variation in this region could predispose to breast cancer. To test this hypothesis, we genotyped tag SNP rs13129471 in 1,261 patients and 825 normal women of African ancestry from three populations. The frequency comparison indicated that rs13129471 was significantly associated with breast cancer after adjusting for ethnicity [P = 0.003; heterozygous odds ratio (OR) 1.02, 95% confidence interval (CI) 0.81-1.28; homozygous OR 1.50, 95% CI 1.15-1.95]. Our results provide new insights into UGT2B4 sequence variation and indicate that a signal of natural selection may lead to the identification of disease susceptibility variants.
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Affiliation(s)
- Chang Sun
- Department of Human Genetics, University of Chicago, 920 E. 58th Street, Chicago, IL 60637, USA
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Statistical power analysis of neutrality tests under demographic expansions, contractions and bottlenecks with recombination. Genetics 2008; 179:555-67. [PMID: 18493071 DOI: 10.1534/genetics.107.083006] [Citation(s) in RCA: 217] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Several tests have been proposed to detect departures of nucleotide variability patterns from neutral expectations. However, very different kinds of evolutionary processes, such as selective events or demographic changes, can produce similar deviations from these tests, thus making interpretation difficult when a significant departure of neutrality is detected. Here we study the effects of demography and recombination upon neutrality tests by analyzing their power under sudden population expansions, sudden contractions, and bottlenecks. We evaluate tests based on the frequency spectrum of mutations and the distribution of haplotypes and explore the consequences of using incorrect estimates of the rates of recombination when testing for neutrality. We show that tests that rely on haplotype frequencies-especially Fs and ZnS, which are based, respectively, on the number of different haplotypes and on the r2 values between all pairs of polymorphic sites-are the most powerful for detecting expansions on nonrecombining genomic regions. Nevertheless, they are strongly affected by misestimations of recombination, so they should not be used when recombination levels are unknown. Instead, class I tests, particularly Tajima's D or R2, are recommended.
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He F, Wu DD, Kong QP, Zhang YP. Intriguing balancing selection on the intron 5 region of LMBR1 in human population. PLoS One 2008; 3:e2948. [PMID: 18698406 PMCID: PMC2492787 DOI: 10.1371/journal.pone.0002948] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 07/18/2008] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The intron 5 of gene LMBR1 is the cis-acting regulatory module for the sonic hedgehog (SHH) gene. Mutation in this non-coding region is associated with preaxial polydactyly, and may play crucial roles in the evolution of limb and skeletal system. METHODOLOGY/PRINCIPAL FINDINGS We sequenced a region of the LMBR1 gene intron 5 in East Asian human population, and found a significant deviation of Tajima's D statistics from neutrality taking human population growth into account. Data from HapMap also demonstrated extended linkage disequilibrium in the region in East Asian and European population, and significantly low degree of genetic differentiation among human populations. CONCLUSION/SIGNIFICANCE We proposed that the intron 5 of LMBR1 was presumably subject to balancing selection during the evolution of modern human.
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Affiliation(s)
- Fang He
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Dong-Dong Wu
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Qing-Peng Kong
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Ya-Ping Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- Laboratory for Conservation and Utilization of Bio-resource, Yunnan University, Kunming, China
- * E-mail:
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Soejima M, Pang H, Koda Y. Genetic variation of FUT2 in a Ghanaian population: identification of four novel mutations and inference of balancing selection. Ann Hematol 2007; 86:199-204. [PMID: 17089126 DOI: 10.1007/s00277-006-0203-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Accepted: 09/11/2006] [Indexed: 11/24/2022]
Abstract
The FUT2 is rich in polymorphisms that show population-specific patterns in its coding sequence. In this study, we found four novel substitutions in 121 Ghanaian samples. In addition, statistical tests considering population expansion scenarios suggested that balancing selection might be responsible for the genetic diversity of FUT2 in this population.
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Affiliation(s)
- Mikiko Soejima
- Department of Forensic Medicine and Human Genetics, Kurume University School of Medicine, Kurume, Japan
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Soejima M, Tachida H, Ishida T, Sano A, Koda Y. Evidence for recent positive selection at the human AIM1 locus in a European population. Mol Biol Evol 2005; 23:179-88. [PMID: 16162863 DOI: 10.1093/molbev/msj018] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Two missense polymorphisms (E272K and L374F) of the AIM1 locus, encoding a melanocyte differentiation antigen, were shown to have a clear association with human ethnicities. These two nonpathogenic single nucleotide polymorphisms (SNPs) may be associated with human pigmentation variation. In this study, we investigated sequence variation in the coding region and exon-flanking sequence and found low genetic variation only in subjects of European descent. All four statistical tests applied to the 7.55-kb region surrounding the L374F polymorphism detected statistically significant deviations from selective neutrality in Europeans. In addition, haplotype analysis revealed that one haplotype carrying 374F was overrepresented in this population, and the low rate of variation, with some features of selective sweeps, was shown to be statistically significant. These results suggest that positive selection recently has been acting or has acted on at least this region of the melanogenic gene and that an advantageous haplotype spread rapidly in Europe.
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Affiliation(s)
- Mikiko Soejima
- Department of Forensic Medicine and Human Genetics, Kurume University School of Medicine, Kurume, Japan
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