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Wade EE, Kyriazis CC, Cavassim MIA, Lohmueller KE. Quantifying the fraction of new mutations that are recessive lethal. Evolution 2023; 77:1539-1549. [PMID: 37074880 PMCID: PMC10309970 DOI: 10.1093/evolut/qpad061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 03/21/2023] [Accepted: 04/14/2023] [Indexed: 04/20/2023]
Abstract
The presence and impact of recessive lethal mutations have been widely documented in diploid outcrossing species. However, precise estimates of the proportion of new mutations that are recessive lethal remain limited. Here, we evaluate the performance of Fit∂a∂i, a commonly used method for inferring the distribution of fitness effects (DFE), in the presence of lethal mutations. Using simulations, we demonstrate that in both additive and recessive cases, inference of the deleterious nonlethal portion of the DFE is minimally affected by a small proportion (<10%) of lethal mutations. Additionally, we demonstrate that while Fit∂a∂i cannot estimate the fraction of recessive lethal mutations, Fit∂a∂i can accurately infer the fraction of additive lethal mutations. Finally, as an alternative approach to estimate the proportion of mutations that are recessive lethal, we employ models of mutation-selection-drift balance using existing genomic parameters and estimates of segregating recessive lethals for humans and Drosophila melanogaster. In both species, the segregating recessive lethal load can be explained by a very small fraction (<1%) of new nonsynonymous mutations being recessive lethal. Our results refute recent assertions of a much higher proportion of mutations being recessive lethal (4%-5%), while highlighting the need for additional information on the joint distribution of selection and dominance coefficients.
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Affiliation(s)
- Emma E Wade
- Department of Ecology and Evolutionary Biology, University of California–Los Angeles, Los Angeles, CA, United States
- Department of Computer Science and Engineering, Mississippi State University, Starkville, MS, United States
| | - Christopher C Kyriazis
- Department of Ecology and Evolutionary Biology, University of California–Los Angeles, Los Angeles, CA, United States
| | - Maria Izabel A Cavassim
- Department of Ecology and Evolutionary Biology, University of California–Los Angeles, Los Angeles, CA, United States
| | - Kirk E Lohmueller
- Department of Ecology and Evolutionary Biology, University of California–Los Angeles, Los Angeles, CA, United States
- Interdepartmental Program in Bioinformatics, University of California–Los Angeles, Los Angeles, CA, United States
- Department of Human Genetics, David Geffen School of Medicine, University of California–Los Angeles, Los Angeles, CA, United States
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Howe O, Lyng FM, Mothersill C. Women's contributions to radiobiology in Ireland; from small beginnings…. Int J Radiat Biol 2021; 98:331-340. [PMID: 34010091 DOI: 10.1080/09553002.2021.1931529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To describe the contribution of women radiobiologists in Ireland to the development of the discipline internationally and at home and to discuss the history of radiobiology in Ireland to date. This parallels the history of the evolution of a small radiobiology group in Kevin Street, Dublin Institute of Technology (DIT) which was formerly part of the City of Dublin Vocational Education Committee. There followed years of development first as a radiobiological research center which evolved in the FOCAS Research Institute now embedded within Technological University Dublin (TU Dublin). CONCLUSIONS Over the last 45 years, the women of the Radiation and Environmental Science Centre (RESC) contributed to the major paradigm shift in low dose radiobiology contributing exciting new research concerning non-targeted effects, including discovery of lethal mutations, medium transfer bystander mechanisms, and signaling pathways. They also developed translational research using human explant culture systems with unique immunocytochemical methods and more recently evolved to molecular and spectroscopic analysis of clinical samples. The RESC also developed unique in vitro research methods into effects of radiation on non-human species of concern in ecosystems.
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Affiliation(s)
- Orla Howe
- School of Biological and Health Sciences, Technological University Dublin, Dublin, Ireland.,Radiation and Environmental Science Centre, FOCAS Research Institute, Dublin, Ireland
| | - Fiona M Lyng
- Radiation and Environmental Science Centre, FOCAS Research Institute, Dublin, Ireland.,School of Physics & Clinical & Optometric Sciences, Technological University Dublin, Dublin, Ireland
| | - Carmel Mothersill
- Radiation and Environmental Science Centre, FOCAS Research Institute, Dublin, Ireland.,Department of Biology, Life Sciences building, McMaster University, Hamilton, Canada
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Mit N, Cherednichenko O, Mussayeva A, Khamdiyeva O, Amirgalieva A, Begmanova M, Tolebaeva A, Koishekenova G, Zaypanova S, Pilyugina A, Amandykova M, Tlenshieva A, Nurzhanova A, Mamirova A, Bekmanov B, Djansugurova L. Ecological risk assessment and long-term environmental pollution caused by obsolete undisposed organochlorine pesticides. J Environ Sci Health B 2021; 56:490-502. [PMID: 34019462 DOI: 10.1080/03601234.2021.1913931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Obsolete organochlorine pesticides (OSPs) are currently prohibited as persistent organic pollutants that contaminate the environment. If undisposed, they continue to pollute soil and water, to accumulate in the food chain and to harm plants, animals and the human body. The aim of the study was to assess water and soil pollution around the storehouses of undisposed, banned OSPs and their possible genotoxic effect. The storehouses in four villages near Almaty, Kazakhstan were investigated. Chemical analysis confirmed contamination of water and soil around storehouses with OSPs. The genotoxic effect of water and soil samples was evaluated using model objects: S.typhymurium, D.melanogaster, sheep lymphocytes cultures and human lymphocytes cultures. It was found that water and soil samples caused mutagenic effect in all model systems. They increased the frequency of revertants in Salmonella, the frequency of lethal mutations in Drosophila chromosomes, and the frequency of chromosome aberrations in cultures of human and sheep lymphocytes. Although a genotoxic effect was demonstrated for each of these models, various models showed different sensitivity to the effects of pesticides and they varied degree of response. The association between the total content of OCPs in soil and the level of mutations for different model systems was discovered.
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Affiliation(s)
- Natalya Mit
- Institute of Genetics and Physiology, Department of molecular genetics, Almaty, Kazakhstan
| | - Oksana Cherednichenko
- Institute of Genetics and Physiology, Department of genetic monitoring, Almaty, Kazakhstan
| | - Aizhan Mussayeva
- Institute of Genetics and Physiology, Department of animal genetics and cytogenetics, Almaty, Kazakhstan
| | - Ozada Khamdiyeva
- Institute of Genetics and Physiology, Department of experimental mutagenesis, Almaty, Kazakhstan
| | - Almira Amirgalieva
- Institute of Genetics and Physiology, Department of molecular genetics, Almaty, Kazakhstan
| | - Mamura Begmanova
- Institute of Genetics and Physiology, Department of molecular genetics, Almaty, Kazakhstan
| | - Anar Tolebaeva
- Institute of Genetics and Physiology, Department of molecular genetics, Almaty, Kazakhstan
| | - Gulshat Koishekenova
- Institute of Genetics and Physiology, Department of experimental mutagenesis, Almaty, Kazakhstan
| | - Saule Zaypanova
- Institute of Genetics and Physiology, Department of experimental mutagenesis, Almaty, Kazakhstan
| | - Anastassiya Pilyugina
- Institute of Genetics and Physiology, Department of genetic monitoring, Almaty, Kazakhstan
| | - Makpal Amandykova
- Institute of Genetics and Physiology, Department of animal genetics and cytogenetics, Almaty, Kazakhstan
- Kazakh National University by al-Farabi, biological faculty, Almaty, Kazakhstan
| | - Arshyn Tlenshieva
- Institute of Genetics and Physiology, Department of animal genetics and cytogenetics, Almaty, Kazakhstan
| | - Asil Nurzhanova
- Institute of Plant Biology and Biotechnology, Department of plant physiology and biochemistry, Almaty, Kazakhstan
| | - Aigerim Mamirova
- Institute of Genetics and Physiology, Department of experimental mutagenesis, Almaty, Kazakhstan
- Kazakh National University by al-Farabi, biological faculty, Almaty, Kazakhstan
| | - Bakhytzhan Bekmanov
- Institute of Genetics and Physiology, Department of molecular genetics, Almaty, Kazakhstan
- Kazakh National University by al-Farabi, biological faculty, Almaty, Kazakhstan
| | - Leyla Djansugurova
- Institute of Genetics and Physiology, Department of molecular genetics, Almaty, Kazakhstan
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Mothersill C, Rusin A, Seymour C. Relevance of Non-Targeted Effects for Radiotherapy and Diagnostic Radiology; A Historical and Conceptual Analysis of Key Players. Cancers (Basel) 2019; 11:E1236. [PMID: 31450803 DOI: 10.3390/cancers11091236] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/16/2019] [Accepted: 08/18/2019] [Indexed: 11/17/2022] Open
Abstract
Non-targeted effects (NTE) such as bystander effects or genomic instability have been known for many years but their significance for radiotherapy or medical diagnostic radiology are far from clear. Central to the issue are reported differences in the response of normal and tumour tissues to signals from directly irradiated cells. This review will discuss possible mechanisms and implications of these different responses and will then discuss possible new therapeutic avenues suggested by the analysis. Finally, the importance of NTE for diagnostic radiology and nuclear medicine which stems from the dominance of NTE in the low-dose region of the dose–response curve will be presented. Areas such as second cancer induction and microenvironment plasticity will be discussed.
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Lalić J, Elena SF. The impact of high-order epistasis in the within-host fitness of a positive-sense plant RNA virus. J Evol Biol 2015; 28:2236-47. [PMID: 26344415 DOI: 10.1111/jeb.12748] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 07/30/2015] [Accepted: 08/20/2015] [Indexed: 01/18/2023]
Abstract
RNA viruses are the main source of emerging infectious diseases because of the evolutionary potential bestowed by their fast replication, large population sizes and high mutation and recombination rates. However, an equally important property, which is usually neglected, is the topography of the fitness landscape. How many fitness maxima exist and how well they are connected is especially interesting, as this determines the number of accessible evolutionary pathways. To address this question, we have reconstructed a region of the fitness landscape of tobacco etch potyvirus constituted by mutations observed during the experimental adaptation of the virus to the novel host Arabidopsis thaliana. Fitness was measured for many genotypes and showed the existence of multiple peaks and holes in the landscape. We found prevailing epistatic effects between mutations, with cases of reciprocal sign epistasis being common among pairs of mutations. We also found that high-order epistasis was as important as pairwise epistasis in their contribution to fitness. Therefore, results suggest that the landscape was rugged due to the existence of holes caused by lethal genotypes, that a very limited number of potential neutral paths exist and that it contained a single adaptive peak.
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Affiliation(s)
- J Lalić
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, València, Spain
| | - S F Elena
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, València, Spain.,The Santa Fe Institute, Santa Fe, NM, USA
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Long HA, Paixão T, Azevedo RBR, Zufall RA. Accumulation of spontaneous mutations in the ciliate Tetrahymena thermophila. Genetics 2013; 195:527-40. [PMID: 23934880 PMCID: PMC3781978 DOI: 10.1534/genetics.113.153536] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 07/19/2013] [Indexed: 11/18/2022] Open
Abstract
Knowledge of the rate and fitness effects of mutations is essential for understanding the process of evolution. Mutations are inherently difficult to study because they are rare and are frequently eliminated by natural selection. In the ciliate Tetrahymena thermophila, mutations can accumulate in the germline genome without being exposed to selection. We have conducted a mutation accumulation (MA) experiment in this species. Assuming that all mutations are deleterious and have the same effect, we estimate that the deleterious mutation rate per haploid germline genome per generation is U=0.0047 (95% credible interval: 0.0015, 0.0125), and that germline mutations decrease fitness by s=11% when expressed in a homozygous state (95% CI: 4.4%, 27%). We also estimate that deleterious mutations are partially recessive on average (h=0.26; 95% CI: -0.022, 0.62) and that the rate of lethal mutations is <10% of the deleterious mutation rate. Comparisons between the observed evolutionary responses in the germline and somatic genomes and the results from individual-based simulations of MA suggest that the two genomes have similar mutational parameters. These are the first estimates of the deleterious mutation rate and fitness effects from the eukaryotic supergroup Chromalveolata and are within the range of those of other eukaryotes.
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Affiliation(s)
- Hong-An Long
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001
- Department of Biology, Indiana University, Bloomington, Indiana 47405
| | - Tiago Paixão
- The Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria
| | - Ricardo B. R. Azevedo
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001
| | - Rebecca A. Zufall
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001
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