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Liu Q, Iqbal MF, Yaqub T, Firyal S, Zhao Y, Stoneking M, Li M. The Transmission of Human Mitochondrial DNA in Four-Generation Pedigrees. Hum Mutat 2022; 43:1259-1267. [PMID: 35460575 DOI: 10.1002/humu.24390] [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: 12/31/2021] [Revised: 04/07/2022] [Accepted: 04/21/2022] [Indexed: 11/06/2022]
Abstract
Most of the pathogenic variants in mitochondrial DNA (mtDNA) exist in a heteroplasmic state (coexistence of mutant and wild-type mtDNA). Understanding how mtDNA is transmitted is crucial for predicting mitochondrial disease risk. Previous studies were based mainly on two-generation pedigree data, which are limited by the randomness in a single transmission. In this study, we analyzed the transmission of heteroplasmies in 16 four-generation families. First, we found that 57.8% of the variants in the great grandmother were transmitted to the fourth generation. The direction and magnitude of the frequency change during transmission appeared to be random. Moreover, no consistent correlation was identified between the frequency changes among the continuous transmissions, suggesting that most variants were functionally neutral or mildly deleterious and thus not subject to strong natural selection. Additionally, we found that the frequency of one nonsynonymous variant (m.15773G>A) showed a consistent increase in one family, suggesting that this variant may confer a fitness advantage to the mitochondrion/cell. We also estimated the effective bottleneck size during transmission to be 21-71. In summary, our study demonstrates the advantages of multigeneration data for studying the transmission of mtDNA for shedding new light on the dynamics of the mutation frequency in successive generations. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Qi Liu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China.,Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Beijing, China
| | - Muhammad Faaras Iqbal
- Department of Human Genetics and Molecular Biology, University of Health Sciences, Lahore, Pakistan.,University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Tahir Yaqub
- University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Sehrish Firyal
- University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Yiqiang Zhao
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Mark Stoneking
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig, Germany.,Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive, UMR 5558, Villeurbanne, France
| | - Mingkun Li
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, China
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Mitochondrial Heteroplasmy Shifting as a Potential Biomarker of Cancer Progression. Int J Mol Sci 2021; 22:ijms22147369. [PMID: 34298989 PMCID: PMC8304746 DOI: 10.3390/ijms22147369] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 02/07/2023] Open
Abstract
Cancer is a serious health problem with a high mortality rate worldwide. Given the relevance of mitochondria in numerous physiological and pathological mechanisms, such as adenosine triphosphate (ATP) synthesis, apoptosis, metabolism, cancer progression and drug resistance, mitochondrial genome (mtDNA) analysis has become of great interest in the study of human diseases, including cancer. To date, a high number of variants and mutations have been identified in different types of tumors, which coexist with normal alleles, a phenomenon named heteroplasmy. This mechanism is considered an intermediate state between the fixation or elimination of the acquired mutations. It is suggested that mutations, which confer adaptive advantages to tumor growth and invasion, are enriched in malignant cells. Notably, many recent studies have reported a heteroplasmy-shifting phenomenon as a potential shaper in tumor progression and treatment response, and we suggest that each cancer type also has a unique mitochondrial heteroplasmy-shifting profile. So far, a plethora of data evidencing correlations among heteroplasmy and cancer-related phenotypes are available, but still, not authentic demonstrations, and whether the heteroplasmy or the variation in mtDNA copy number (mtCNV) in cancer are cause or consequence remained unknown. Further studies are needed to support these findings and decipher their clinical implications and impact in the field of drug discovery aimed at treating human cancer.
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McGrath C. Human Genetics: A Look in the Mirror. Genome Biol Evol 2020. [DOI: 10.1093/gbe/evaa139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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