Large-scale changes are common in genomes, and are often associated with pathological disorders. In the work presented in this dissertation, I provide insights into how inverted repeat sequences in budding yeast fuse during replication. Fusion leads to the formation of dicentric chromosomes, a translocation, and other chromosomal rearrangements.Using extensive genetics and some molecular analyses, I demonstrate that dicentric chromosomes are key intermediates in genome instability of a specific chromosome in budding yeast. I provide three pieces of evidence that is consistent with this conclusion. First, I detect a recombination fusion junction that is diagnostic of a dicentric chromosome (using a PCR technique). Second, I show a strong correlation between the amount of the dicentric fragment and the frequency of instability of the entire chromosome. Third, I demonstrate that a mutant known to stabilize dicentric chromosomes suppress instability. Based on these observations, I conclude that dicentric chromosomes are intermediates in causing genome instability in this system.Next, we demonstrate that fusion of inverted repeats is general. Both endogenous and synthetic nearby inverted repeats can fuse. Using genetics, I also show that many DNA repair and checkpoint pathways suppress fusion of nearby inverted repeats and genome instability. Based on our analysis, we propose a novel mechanism for fusion of inverted repeats that we term `faulty template switching.'Lastly, I discuss two genes that are necessary for fusion of nearby inverted repeats. I identified a mutant of the Exonuclease 1 (Exo1) and a mutant of anaphase inhibitor securin (Pds1) that suppress nearby inverted repeat fusion and genome instability. Studies of Exo1 and Pds1 provide us with insights into the molecular mechanisms of fusion.Our finding that nearby inverted repeats can fuse to form dicentric chromosomes that lead to genome instability may have great implications. The generality of this fusion reaction raises the possibility that dicentric chromosomes formed by inverted repeats can lead to genome instability in mammalian cells, and thereby contribute to a cancer phenotype.

Chez les eucaryotes, le génome est organisé en chromatine, une structure nucléoprotéique essentielle pour la régulation de l’expression génique ainsi que pour le maintien de la stabilité du génome. Les ciliés sont d’excellents organismes modèles pour étudier les mécanismes généraux qui maintiennent l’intégrité du génomes eucaryote. Chez Paramecium tetraurelia, la différentiation du génome somatique à partir du génome germinal est caractérisée par des événements massifs et reproductibles d’élimination d’ADN. D’une part, des éléments répétés (transposons,régions minisatellites), de plusieurs kilobases de long, sont imprécisément éliminés.D’autre part, 45000 séquences courtes et uniques, appelées IES, sont précisément éliminées au nucléotide près. Une classe de petits ARN, appelé scnRNAs, est impliquée dans la régulation epigénétique de l’élimination d’ADN, mais comment les scnRNA contrôlent l’élimination d’ADN reste mystérieux. Nous avons testé l’hypothèse selon laquelle une organisation particulière de la chromatine, en particulier des modifications post-traductionelles des histones associées à des formes répressives de la chromatine, est impliquée dans le processus d’élimination d’ADN. Nous avons montré que la triméthylation de l’histone H3 sur la lysine 9 et la lysine 27 (H3K9me3 et H3K27me3)apparaît transitoirement dans le noyau somatique en développement au moment où se produisent les événements d’élimination d’ADN. Nous avons identifié la protéine de type Polycomb, Ezl1, et montré qu’elle est une histone methyltransferase qui présente une dualité de substrat et catalyse à la fois la mise en place de K9me3 et K27me3 sur l’histone H3. Nous avons montré que la déposition de H3K9me3 et H3K27me3 dans le noyau en développement requiert les scnRNAs. Des analyses de séquençage haut débit ont montré que Ezl1 est requise pour l’élimination des longues séquences répétées germinales, suggérant que les scnRNA guident la déposition des marques d’histones au niveau de ces séquences. Au contraire des régions répétées du génome, les IES montrent une sensibilité différente aux scnRNAs et à Ezl1, suggérant que plusieurs voies partiellement chevauchantes sont impliquées dans leur élimination. Notre étude montre que des caractéristiques intrinsèques des séquences d’ADN, telles que leur taille, peut contribuer à la définition des séquences germinales à éliminer. De manière intéressante, nous avons aussi montré que Ezl1 est requise pour la répression transcriptionnelle des éléments transposables. Nous suggérons que les voies H3K9me3et H3K27me3 coopèrent et contribuent à préserver le génome somatique de Paramecium des parasites génomiques. / Eukaryotic genomes are organized into chromatin, a complex nucleoprotein structureessential for the regulation of gene expression and for maintaining genome stability.Ciliates provide excellent model organisms with which to gain better understandinginto the regulation of genome stability in eukaryotes. In the ciliate Parameciumtetraurelia, differentiation of the somatic genome from the germline genome ischaracterized by massive and reproducible programmed DNA elimination events. Longregions of several kilobases in length, containing repeated sequences and transposableelements are imprecisely eliminated, whereas 45,000 short, dispersed, single-copyInternal Eliminated Sequences (IESs) are precisely excised at the nucleotide level. Aspecific class of small RNAs, called scnRNAs, is involved in the epigenetic regulation ofDNA deletion. How scnRNAs may guide DNA elimination in Paramecium remains tobe discovered. Here, we investigated whether chromatin structure, in particular histonepost-translational modifications known to be associated with repressive chromatin,might control DNA elimination. We showed that trimethylated lysine 9 and 27 onhistone H3 (H3K9me3 and H3K27me3) appear in the developing somaticmacronucleus when DNA elimination occurs. We identified the Polycomb-groupprotein, Ezl1, and showed that it is a dual histone methyltransferase that catalyzes bothH3K9me3 and H3K27me3 in vitro and in vivo. Genome-wide analyses show thatscnRNA-mediated H3K9me3 and H3K27me3 deposition is necessary for theelimination of long, repeated germline DNA. Conversely, single copy IESs displaydifferential sensitivity to depletion of scnRNAs and Ezl1, unveiling the existence ofpartially overlapping pathways in programmed DNA elimination. Our study revealsthat cis-acting determinants, such as DNA length, also contribute to the definition ofgermline sequences to delete. We further showed that Ezl1 is required fortranscriptional repression of transposable elements. We suggest that H3K9me3 andH3K27me3 pathways cooperate and contribute to safeguard the Paramecium somaticgenome against intragenomic parasites.

Determining the properties of mutations is fundamental to understanding the mechanisms of adaptive evolution. The major goal of this thesis is to investigate the mechanisms of bacterial adaptation to new environments using experimental evolution. Different types of mutations were under investigations with a particular focus on genome rearrangements. Adaptive evolution experiments were focused on the development of bacterial resistance to antibiotics. In paper I, we performed stochastic simulations to examine the role of gene amplification in promoting the establishment of new gene functions. The results show that gene amplification can contribute to creation of new gene functions in nature. In paper II, the evolution of β-lactam resistance was studied by evolving S. typhimurium carrying a β-lactamase gene towards increased resistance against cephalosporins. Our results suggest that gene amplification is likely to provide an immediate solution at the early stage of adaptive evolution and subsequently facilitate further stable adaptation. In paper III, we isolated spontaneous deletion mutants with increased competitive fitness, which indicated that genome reduction could be driven by selection. To test this hypothesis, independent lineages of wild type S. typhimurium were serially passaged for 1000 generations and we observed fixation of deletions that significantly increased bacterial fitness when reconstructed in wild type genetic background. In paper IV, we developed a new strategy combining 454 pyrosequencing technology and a ‘split mapping’ computational method to identify unique junction sequences formed by spontaneous genome rearrangements. A high steady-state frequency of rearrangements in unselected bacterial populations was suggested from our results. In paper V, the rates, mechanisms and fitness effects of colistin resistance in S. typhimurium were determined. The high mutation rate and low fitness costs suggest that colistin resistance could develop in clinical settings. In paper VI, a novel Metallo-β-lactamase (MBL) with low resistance against β-lactam antibiotics was employed as the ancestral protein in a directed evolution experiment to examine how an enzyme evolves towards increased resistance. For most isolated mutants, in spite of their significantly increased resistance, both mRNA and protein levels were decreased as compared with the parental protein, suggesting that the catalytic activity had increased.

A central topic of evolutionary biology is the inference of phylogeny, i. e., the evolutionary history of species. A powerful tool for the inference of such phylogenetic relationships is the arrangement of the genes in mitochondrial genomes. The rationale is that these gene arrangements are subject to different types of mutations in the course of evolution. Hence, a high similarity in the gene arrangement between two species indicates a close evolutionary relation. Metazoan mitochondrial gene arrangements are particularly well suited for such phylogenetic studies as they are available for a wide range of species, their gene content is almost invariant, and usually free of duplicates. With these properties gene arrangements of mitochondrial genomes are modeled by permutations in which each element represents a gene, i. e., a specific genetic sequence. The mutations that shape the gene arrangement of genomes are then represented by operations that rearrange elements in permutations, so-called genome rearrangements, and thereby bridge the gap between evolutionary biology and optimization. Many problems of phylogeny inference can be formulated as challenging combinatorial optimization problems which makes this research area especially interesting for computer scientists. The most prominent examples of such optimization problems are the sorting problem and the distance problem. While the sorting problem requires a minimum length sequence of rearrangements that transforms one given permutation into another given permutation, i. e., it aims for a hypothetical scenario of gene order evolution, the distance problem intends to determine only the length of such a sequence. This minimum length is called distance and used as a (dis)similarity measure quantifying the evolutionary relatedness. Most evolutionary changes occurring in gene arrangements of mitochondrial genomes can be explained by the tandem duplication random loss (TDRL) genome rearrangement model. A TDRL consists of a duplication of a consecutive set of genes in tandem followed by a random loss of one copy of each duplicated gene. In spite of the importance of the TDRL genome rearrangement in mitochondrial evolution, its combinatorial properties have rarely been studied. In addition, models of genome rearrangements which include all types of rearrangement that are relevant for mitochondrial genomes, i. e., inversions, transpositions, inverse transpositions, and TDRLs, while admitting computational tractability are rare. Nevertheless, especially for metazoan gene arrangements the TDRL rearrangement should be considered for the reconstruction of phylogeny. Realizing that a better understanding of the TDRL model is indispensable for the study of mitochondrial gene arrangements, the central theme of this thesis is to broaden the horizon of TDRL genome rearrangements with respect to mitochondrial genome evolution. For this purpose, this thesis provides combinatorial properties of the TDRL model and its variants as well as efficient methods for a plausible reconstruction of rearrangement scenarios between gene arrangements. The methods that are proposed consider all types of genome rearrangements that predominately occur during mitochondrial evolution. More precisely, the main points contained in this thesis are as follows: The distance problem and the sorting problem for the TDRL model are further examined in respect to circular permutations, a formal concept that reflects the circular structure of mitochondrial genomes. As a result, a closed formula for the distance is provided. Recently, evidence for a variant of the TDRL rearrangement model in which the duplicated set of genes is additionally inverted have been found. Initiating the algorithmic study of this new rearrangement model on a certain type of permutations, a closed formula solving the distance problem is proposed as well as a quasilinear time algorithm that solves the corresponding sorting problem. The assumption that only one type of genome rearrangement has occurred during the evolution of certain gene arrangements is most likely unrealistic, e. g., at least three types of rearrangements on top of the TDRL rearrangement have to be considered for the evolution metazoan mitochondrial genomes. Therefore, three different biologically motivated constraints are taken into account in this thesis in order to produce plausible evolutionary rearrangement scenarios. The first constraint is extending the considered set of genome rearrangements to the model that covers all four common types of mitochondrial genome rearrangements. For this 4-type model a sharp lower bound and several close additive upper bounds on the distance are developed. As a byproduct, a polynomial-time approximation algorithm for the corresponding sorting problem is provided that guarantees the computation of pairwise rearrangement scenarios that deviate from a minimum length scenario by at most two rearrangement operations. The second biologically motivated constraint is the relative frequency of the different types of rearrangements occurring during the evolution. The frequency is modeled by employing a weighting scheme on the 4-type model in which every rearrangement is weighted with respect to its type. The resulting NP-hard sorting problem is then solved by means of a polynomial size integer linear program. The third biologically motivated constraint that has been taken into account is that certain subsets of genes are often found in close proximity in the gene arrangements of many different species. This observation is reflected by demanding rearrangement scenarios to preserve certain groups of genes which are modeled by common intervals of permutations. In order to solve the sorting problem that considers all three types of biologically motivated constraints, the exact dynamic programming algorithm CREx2 is proposed. CREx2 has a linear runtime for a large class of problem instances. Otherwise, two versions of the CREx2 are provided: The first version provides exact solutions but has an exponential runtime in the worst case and the second version provides approximated solutions efficiently. CREx2 is evaluated by an empirical study for simulated artificial and real biological mitochondrial gene arrangements.

L’élimination programmée d’ADN spécifique de la lignée germinale pour former un nouveau noyau somatique a été décrite chez les eucaryotes. Ces réarrangements sont initiés par l’introduction de cassures double brin (CDB) de l’ADN et la préservation de l’intégrité du génome requiert une réparation efficace. Chez Paramecium tetraurelia, le génome est largement réarrangé pendant le développement du nouveau noyau somatique, après l’introduction de milliers de cassures double brin programmées par la transposase domestiquée PiggyMac (Pgm)Ces réarrangements consistent en l’excision précise de dizaines de milliers de séquences uniques et non codantes (IES) qui interrompent 47% des gènes dans la lignée germinale ; et l’élimination hétérogène de séquences répétées qui mène à des délétions internes de taille variable ou à la fragmentation des chromosomes avec addition de télomères aux extrémités.L’implication de la voie du Non Homologous End Joining (NHEJ) dans l’excision précise des IES a été prouvée. Dans des cellules déplétées de Ligase IV ou XRCC4, les cassures aux bornes des IES sont introduites normalement mais il n’y a pas de jonctions d’excision formées et les extrémités cassées s’accumulent sans être dégradées. Mais la voie de réparation impliquée dans les réarrangements imprécis est encore inconnue. L’hypothèse d’une réparation par la voie NHEJ alternative (alt-NHEJ), indépendante de Ku et impliquant la résection des extrémités et l’utilisation de microhomologie, a été émise. C’est pourquoi pendant ma thèse je me suis intéressé à ma thèse au rôle des protéines Ku.Deux gènes KU70 et trois gènes KU80 ont été identifiés dans le génome de la paramécie. KU70a et KU80c sont spécifiquement induits pendant les réarrangements programmés du génome et les protéines localisent dans les noyaux somatiques en développement. Des expériences d’extinction de ces gènes par ARN interférence ont prouvé que ces gènes étaient indispensables. Au niveau moléculaire, l’ADN non réarrangé est amplifié dans les cellules déplétées de Ku. De plus, les cassures double brin programmées ne sont pas introduites aux bornes des IES.Mes résultats suggèrent que Ku fait partie d’un complexe de pré-excision, avec la transposase domestiquée Pgm, et est nécessaire pour l’introduction des cassures double brin programmées pendant les réarrangements programmés du génome. / Programmed elimination of germline specific DNA has been described in several eukaryotic organisms. These rearrangements are initiated through introduction of DNA double strand breaks (DSB). To ensure genome integrity, efficient repair is needed. In Paramecium tetraurelia, the genome is widely rearranged during development of a new somatic nucleus after introduction of tens of thousands of DSBs by the domesticated transposase PiggyMac (Pgm)These rearrangements consist in: the precise excision of thousands of unique and non coding sequences called IESs that interrupt 47% of genes in the germline; and the heterogeneous elimination of repeated sequences. It leads to internal deletions of variable sizes or to chromosome fragmentation with telomere addition at DNA ends.Implication of the Non Homologous End Joining Pathway (NHEJ) in precise IES excision has been proved. In cells depleted for Ligase IV or XRCC4, DSBs at IES boundaries are introduced normally but broken DNA ends accumulate without being repaired nor degraded. The repair pathway implicated in heterogeneous rearrangements is still unknown. An hypothesis would be that heterogeneous rearrangements involve a Ku independent alternative NHEJ (alt-NHEJ) pathway characterized by end resection and use of microhomologies. During my thesis I studied the role of Ku proteins in programmed genome rearrangements.Two KU70 genes and three KU80 genes has been identified in the Paramecium genome. KU70a and KU80c are specifically induced during programmed genome rearrangements. Encoded proteins localize in developing somatic nuclei. Gene extinction by RNA interference experiments proved that these genes are necessary for programmed genome rearrangements. At molecular level, non rearranged DNA is amplified in cells depleted for Ku. And more surprisingly, no programmed DSBs are introduced at IES boundaries in these cells.My results indicate that Ku is a part of a pre excision complex with the domesticated transposase Pgm and necessary for the introduction of programmed DSB during programmed genome rearrangements.

An implementation framework has been developed in this thesis for a well-known APX-hard combinatorial optimization problem known as Block Sorting. The motivation for the study of this problem comes from applications such as computational biology and optical character recognition. While existing Block Sorting research has been theoretically focused on the development and analysis of several approximation algorithms for Block Sorting, little or no work has been carried out thus far on the implementation of the proposed approximation algorithms. The conceptualization of an implementation framework and illustrating its use by experimenting with the existing approximation algorithms will provide means for discovering newer approaches to handling this important problem. As the main contribution, the research in this thesis provides a new greedy algorithm for Block Sorting in which each block move either reduces the number of blocks by two or three blocks, or reduces by one the number of reversals or inversions in the orig- inal permutation. Experimental results for all algorithms are also provided along with a comparison of their performance using the number of block moves and approximation ratios as performance metrics when sorting permutations of a given order, and as the order of permutations is varied. Preliminary results from the experimentation were shared at the 2017 IEEE 17th International Conference on Bioinformatics and Bioengineering (BIBE) [1]. To the best of our knowledge, this is the first work that has been focused on the implementation and experimental performance analysis of any algorithm for Block Sorting. We believe the results presented in this thesis will be useful for researchers and practitioners working in this area.

No description available.

Les champignons mycorhiziens à arbuscules (CMA) sont des organismes microscopiques du sol qui jouent un rôle crucial dans les écosystèmes naturels et que l’on retrouve dans tous les habitats de la planète. Ils vivent en relation symbiotique avec la vaste majorité des plantes terrestres. Ils sont des biotrophes obligatoires, c'est-à-dire qu'ils ne peuvent croître qu'en présence d'une plante hôte. Cette symbiose permet entre autres à la plante d'acquérir des nutriments supplémentaires, en particulier du phosphore et du nitrate. Malgré le fait que cette symbiose apporte des services importants aux écosystèmes, la richesse des espèces, la structure des communautés, ainsi que la diversité fonctionnelle des CMA sont mal connues et l'approfondissement des connaissances dans ces domaines dépend d’outils de diagnostic moléculaire. Cependant, la présence de polymorphisme nucléaire intra-isolat combiné à un manque de données génomiques dans différents groupes phylogénétique de ces champignons complique le développement de marqueurs moléculaires et la détermination de l'affiliation évolutive à hauts niveaux de résolution (c.a.d. entre espèces génétiquement similaires et/ou isolats de la même espèce). . Pour ces raisons, il semble une bonne alternative d’utiliser un système génétique différent en ciblant le génome mitochondrial, qui a été démontré homogène au sein d'un même isolat de CMA. Cependant, étant donné le mode de vie particulier de ces organismes, une meilleure compréhension des processus évolutifs mitochondriaux est nécessaire afin de valoriser l'utilisation de tels marqueurs dans des études de diversité et en génétique des populations. En ce sens, mon projet de doctorat consistait à investiguerétudier: i) les vecteurs de divergences inter-isolats et -espèces génétiquement rapprochéesphylogénétiquement apparentées, ii) la plasticité des génomes mitochondriaux, iii) l'héritabilité mitochondriale et les mécanismes potentiels de ségrégation, ainsi que iv) la diversité mitochondriale intra-isolat in situ. À l'aide de la génomique mitochondriale comparative, en utilisant le séquençage nouvelle génération, on a démontré la présence de variation génétique substantielle inter-isolats et -espèces, engendrées par l'invasion d'éléments mobiles dans les génomes mitochondriaux des CMA, donnant lieu à une évolution moléculaire rapide des régions intergéniques. Cette variation permettait de développer des marqueurs spécifiques à des isolats de la même espèce. Ensuite, à l'aide d'une approche analytique par réseaux de gènes sur des éléments mobiles, on a été en mesure de démontrer des évènements de recombinaisons homologues entre des haplotypes mitochondriaux distincts, menant à des réarrangements génomiques. Cela a permis d'ouvrir les perspectives sur la dynamique mitochondriale et l'hétéroplasmie dans un même isolatsuggère une coexistence de différents haplotypes mitochondriaux dans les populations naturelles et que les cultures monosporales pourraient induirent une sous-estimation de la diversité allélique mitochondriale. Cette apparente contradiction avec l'homogénéité mitochondriale intra-isolat généralement observée, a amené à investiguer étudier les échanges génétiques à l'aide de croisements d'isolats génétiquement distincts. Malgré l'observation de quelques spores filles hétéroplasmiques, l'homoplasmie était le statut par défaut dans toutes les cultures monosporales, avec un biais en faveur de l'un des haplotypes parentaux. Ces résultats suggèrent que la ségrégation opère durant la formation de la spore et/ou le développement de la coloniedu mycélium. De plus, ils supportent la présence d'une machinerie protéique de ségrégation mitochondriale chez les CMAAMF, où l'ensemble des gènes impliqués dans ce mécanisme ont été retrouvé et sont orthologues aux autres champignons. Finalement, on est revenue aux sources avecon a étudié le polymorphisme mitochondrial intra-isolat à l'aide d'une approche conventionnelle de PCR en utilisant une Taq polymérase de haute fidélité, suivie de clonage et de séquençage Sanger, sur deux isolats de R. irregularis. Cela a permis l'observation d'hétéroplasmie in situ, ainsi que la co-expression de variantes de variantes de protéines'ARNm dans une souche in vitro. Les résultats suggèrent que d'autres études basées sur le séquençage nouvelle génération aurait potentiellement ignorée cette variation, offrant ainsi plusieurs nouveaux arguments permettant de considérer les CMA comme des organismes possédant une population de génomes mitochondriaux et nucléaires distincts. / The association between arbuscular mycorrhizal fungi (AMF) and plant roots is one of the most widespread symbioses involving plants, and thus has an important role in terrestrial ecosystems. In exchange for carbohydrates, AMF improve plant fitness by enhancing mineral nutrient uptake, especially in particular phosphate and nitrate. Although this symbiosisDespite the fact that these symbioses contribute provides to important services toin ecosystems, the species richness, community structure and functional diversity of AMF is not well understood due to a lack of reliable molecular tools. The intra-isolate genetic polymorphism of nuclear DNA observed in AMF, combined with a lack of genomic data in a broad range of phylogenetic groups, has made it difficult to develop molecular markers and to determine evolutionary relatedness at high levels of resolution (i.e. between genetically-similar species and/or isolates). For these reasons, it seems a good alternative to use a different genetic system by targeting the mitochondrial genome, which have been shown to be homogeneous within AMF isolates. However, given the peculiar lifestyle of these organisms, a better understanding of the mitochondrial evolutionary processes and dynamics were is necessary in order to validate the usefulness of such markers in diversity and population genetics studies. In that regard, the objectives of my PhD project were to investigate: i) the divergence between closely related species and isolates, ii) mitochondrial genomes plasticity, iii) mitochondrial heritability and potential segregation mechanisms and iv) in situ mitochondrial intra-isolate allelic diversity. With Using comparative mitochondrial genomics using and next generation sequencing (NGS) sequencing, we found substantial sequence variation in intergenic regions caused by the invasion of mobile genetic elements. This variation gives risecontributes to rapid mitochondrial genome evolution among closely related isolates and species, which makes it possible to design reliable intra- and inter-specific markers. Also, an extensive gene similarity network-based approach allowed us to provide strong evidence of inter-haplotype recombination in AMF, leading to a reshuffled mitochondrial genome. These findings suggest the coexistence of distinct mtDNA haplotypes in natural populations and raise questions as to whether AMF single spore cultivations artificially underestimates mitochondrial genetic diversity in natural population.. This apparent contradiction with the intra-isolate mtDNA homogeneity usually observed in these fungi, led to the investigation of mitochondrial heritability in the spore progeny resulting from crossed-cultures. Although an heteroplasmic state was observed in some daughter spores, we found that homoplasmy was the dominant state in all monosporal cultures, with an apparent bias towards one of the parental haplotypes. These results strongly support the presence of a putative mitochondrial segregation proteic machinery in AMF, whose complete set of genes were orthologous with those found in other fungi. Our findings suggest that segregation takes place either during spore formation or colony mycelium development. Finally, we performed a conventional PCR based approach with a high fidelity Taq polymerase, followed by downstream cloning and Sanger sequencing using the model organism Rhizophagus irregularis. We found in situ heteroplasmy along with substantial intra-isolate allelic variation within the mtDNA that persists in the transcriptome. Our study also suggest that genetic variation in Glomeromycota is higher than meets the eye and might be critically underestimated in most NGS based-AMF studies both in nuclei and mitochondria.