MitoRS, a method for high throughput, sensitive, and accurate detection of mitochondrial DNA heteroplasmy

BMC Genomics

Methodology Article

Frédéric Ronga¹  Yiannis A. I. Kourmpetis²  Gregory Lefebvre²  Patrick Descombes²  Julien Marquis²  Mohamed Kassam²  Umberto De Marchi³  Andreas Wiederkehr³ 

[1] Digital Nutrition and Health, Nestlé Institute of Health Sciences, 1015, Lausanne, Switzerland;Functional Genomics, Nestlé Institute of Health Sciences, 1015, Lausanne, Switzerland;Mitochondrial Functions, Nestlé Institute of Health Sciences, 1015, Lausanne, Switzerland;

关键词: Next generation sequencing;    Mitochondria;    Mitochondrial DNA;    Heteroplasmy;    Rolling circle amplification;    Somatic mutation;    Low frequency variant;    MitoRS;   

DOI  :  10.1186/s12864-017-3695-5

 received in 2016-10-03, accepted in 2017-04-10,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundMitochondrial dysfunction is linked to numerous pathological states, in particular related to metabolism, brain health and ageing. Nuclear encoded gene polymorphisms implicated in mitochondrial functions can be analyzed in the context of classical genome wide association studies. By contrast, mitochondrial DNA (mtDNA) variants are more challenging to identify and analyze for several reasons. First, contrary to the diploid nuclear genome, each cell carries several hundred copies of the circular mitochondrial genome. Mutations can therefore be present in only a subset of the mtDNA molecules, resulting in a heterogeneous pool of mtDNA, a situation referred to as heteroplasmy. Consequently, detection and quantification of variants requires extremely accurate tools, especially when this proportion is small. Additionally, the mitochondrial genome has pseudogenized into numerous copies within the nuclear genome over the course of evolution. These nuclear pseudogenes, named NUMTs, must be distinguished from genuine mtDNA sequences and excluded from the analysis.ResultsHere we describe a novel method, named MitoRS, in which the entire mitochondrial genome is amplified in a single reaction using rolling circle amplification. This approach is easier to setup and of higher throughput when compared to classical PCR amplification. Sequencing libraries are generated at high throughput exploiting a tagmentation-based method. Fine-tuned parameters are finally applied in the analysis to allow detection of variants even of low frequency heteroplasmy. The method was thoroughly benchmarked in a set of experiments designed to demonstrate its robustness, accuracy and sensitivity. The MitoRS method requires 5 ng total DNA as starting material. More than 96 samples can be processed in less than a day of laboratory work and sequenced in a single lane of an Illumina HiSeq flow cell. The lower limit for accurate quantification of single nucleotide variants has been measured at 1% frequency.ConclusionsThe MitoRS method enables the robust, accurate, and sensitive analysis of a large number of samples. Because it is cost effective and simple to setup, we anticipate this method will promote the analysis of mtDNA variants in large cohorts, and may help assessing the impact of mtDNA heteroplasmy on metabolic health, brain function, cancer progression, or ageing.

【 授权许可】

CC BY   
© The Author(s). 2017