scholarly journals Combinations ofSpokgenes create multiple meiotic drivers inPodospora

2019 ◽  
Author(s):  
Aaron A. Vogan ◽  
S. Lorena Ament-Velásquez ◽  
Alexandra Granger-Farbos ◽  
Jesper Svedberg ◽  
Eric Bastiaans ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Gene Family ◽  
Natural Populations ◽  
Genomic Data ◽  
Meiotic Drive ◽  
Kinase Domain ◽  
Podospora Anserina ◽  
Spore Killing ◽  
The Individual ◽  
Natural Strains

AbstractMeiotic drive is the preferential transmission of a particular allele at a given locus during sexual reproduction. The phenomenon is observed as spore killing in a variety of fungal lineages, includingPodospora. In natural populations ofPodospora anserina, seven spore killers (Psks) have been identified through classical genetic analyses. Here we show that theSpokgene family underlie thePskspore killers. The combination of the variousSpokgenes at different chromosomal locations defines the spore killers and creates a killing hierarchy within the same population. We identify two novelSpokhomologs that are located within a complex region (theSpokblock) that reside in different chromosomal locations in given natural strains. We confirm that the individual SPOK proteins perform both the killing and resistance functions and show that these activities are dependent on distinct domains, a nuclease and a kinase domain respectively. Genomic data and phylogenetic analysis across ascomycetes suggest that theSpokgenes disperse via cross-species transfer, and evolve by duplication and diversification within several lineages.

scholarly journals Combinations of Spok genes create multiple meiotic drivers in Podospora

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Aaron A Vogan ◽  
S Lorena Ament-Velásquez ◽  
Alexandra Granger-Farbos ◽  
Jesper Svedberg ◽  
Eric Bastiaans ◽  
...  
Keyword(s):  
Gene Family ◽  
Sexual Reproduction ◽  
Phylogenetic Analyses ◽  
Natural Populations ◽  
Meiotic Drive ◽  
Kinase Domain ◽  
Podospora Anserina ◽  
Spore Killing ◽  
Different Strains ◽  
Spore Killer

Meiotic drive is the preferential transmission of a particular allele during sexual reproduction. The phenomenon is observed as spore killing in multiple fungi. In natural populations of Podospora anserina, seven spore killer types (Psks) have been identified through classical genetic analyses. Here we show that the Spok gene family underlies the Psks. The combination of Spok genes at different chromosomal locations defines the spore killer types and creates a killing hierarchy within a population. We identify two novel Spok homologs located within a large (74–167 kbp) region (the Spok block) that resides in different chromosomal locations in different strains. We confirm that the SPOK protein performs both killing and resistance functions and show that these activities are dependent on distinct domains, a predicted nuclease and kinase domain. Genomic and phylogenetic analyses across ascomycetes suggest that the Spok genes disperse through cross-species transfer, and evolve by duplication and diversification within lineages.

scholarly journals An introgressed gene causes meiotic drive in Neurospora sitophila

2020 ◽  
Author(s):  
Jesper Svedberg ◽  
Aaron A. Vogan ◽  
Nicholas A. Rhoades ◽  
Dilini Sarmarajeewa ◽  
David J. Jacobson ◽  
...  
Keyword(s):  
Rna Interference ◽  
Natural Populations ◽  
Meiotic Drive ◽  
Host Genome ◽  
Origin And Evolution ◽  
Filamentous Ascomycete ◽  
Selfish Genes ◽  
A Genome ◽  
Spore Killing ◽  
Spore Killer

AbstractMeiotic drive elements cause their own preferential transmission following meiosis. In fungi this phenomenon takes the shape of spore killing, and in the filamentous ascomycete Neurospora sitophila, the Sk-1 spore killer element is found in many natural populations. In this study, we identify the gene responsible for spore killing in Sk-1 by generating both long and short-read genomic data and by using these data to perform a genome wide association test. Through molecular dissection, we show that a single 405 nucleotide long open reading frame generates a product that both acts as a poison capable of killing sibling spores and as an antidote that rescues spores that produce it. By phylogenetic analysis, we demonstrate that the gene is likely to have been introgressed from the closely related species N. hispaniola, and we identify three subclades of N. sitophila, one where Sk-1 is fixed, another where Sk-1 is absent, and a third where both killer and sensitive strain are found. Finally, we show that spore killing can be suppressed through an RNA interference based genome defense pathway known as meiotic silencing by unpaired DNA. Spk-1 is not related to other known meiotic drive genes, and similar sequences are only found within Neurospora. These results shed new light on the diversity of genes capable of causing meiotic drive, their origin and evolution and their interaction with the host genome.Significance StatementIn order to survive, most organisms have to deal with parasites. Such parasites can be other organisms, or sometimes, selfish genes found within the host genome itself. While much is known about parasitic organisms, the interaction with their hosts and their ability to spread within and between species, much less is known about selfish genes. We here identify a novel selfish “spore killer” gene in the fungus Neurospora sitophila. The gene appears to have evolved within the genus, but has entered the species through hybridization and introgression. We also show that the host can counteract the gene through RNA interference. These results shed new light on the diversity of selfish genes in terms of origin, evolution and host interactions.

scholarly journals Spore-Killing Meiotic Drive Factors in a Natural Population of the Fungus Podospora anserina

Genetics ◽  
2000 ◽  
Vol 156 (2) ◽  
pp. 593-605 ◽  
Author(s):  
Marijn van der Gaag ◽  
Alfons J M Debets ◽  
Jessica Oosterhof ◽  
Marijke Slakhorst ◽  
Jessica A G M Thijssen ◽  
...  
Keyword(s):  
Linkage Group ◽  
The Netherlands ◽  
Natural Population ◽  
Local Population ◽  
Meiotic Drive ◽  
Podospora Anserina ◽  
Group Iii ◽  
Spore Killing ◽  
Different Types ◽  
Spore Killer

Abstract In fungi, meiotic drive is observed as spore killing. In the secondarily homothallic ascomycete Podospora anserina it is characterized by the abortion of two of the four spores in the ascus. We have identified seven different types of meiotic drive elements (Spore killers). Among 99 isolates from nature, six of these meiotic drive elements occurred in a local population. Spore killers comprise 23% of the natural population of P. anserina in Wageningen, The Netherlands, sampled from 1991 to 1997. One Spore-killer type was also found in a French strain dating from 1937. All other isolates found so far are sensitive to spore killing. All seven Spore killer types differ in the percentage of asci that show killing and in their mutual interactions. Interactions among Spore killer types showed either mutual resistance or dominant epistasis. Most killer elements could be assigned to linkage group III but are not tightly linked to the centromere.

scholarly journals An introgressed gene causes meiotic drive in Neurospora sitophila

2021 ◽  
Vol 118 (17) ◽  
pp. e2026605118
Author(s):  
Jesper Svedberg ◽  
Aaron A. Vogan ◽  
Nicholas A. Rhoades ◽  
Dilini Sarmarajeewa ◽  
David J. Jacobson ◽  
...  
Keyword(s):  
Natural Populations ◽  
Meiotic Drive ◽  
Reading Frame ◽  
Origin And Evolution ◽  
Filamentous Ascomycete ◽  
Genome Defense ◽  
Genome Wide ◽  
A Genome ◽  
Spore Killing ◽  
Spore Killer

Meiotic drive elements cause their own preferential transmission following meiosis. In fungi, this phenomenon takes the shape of spore killing, and in the filamentous ascomycete Neurospora sitophila, the Sk-1 spore killer element is found in many natural populations. In this study, we identify the gene responsible for spore killing in Sk-1 by generating both long- and short-read genomic data and by using these data to perform a genome-wide association test. We name this gene Spk-1. Through molecular dissection, we show that a single 405-nt-long open reading frame generates a product that both acts as a poison capable of killing sibling spores and as an antidote that rescues spores that produce it. By phylogenetic analysis, we demonstrate that the gene has likely been introgressed from the closely related species Neurospora hispaniola, and we identify three subclades of N. sitophila, one where Sk-1 is fixed, another where Sk-1 is absent, and a third where both killer and sensitive strain are found. Finally, we show that spore killing can be suppressed through an RNA interference-based genome defense pathway known as meiotic silencing by unpaired DNA. Spk-1 is not related to other known meiotic drive genes, and similar sequences are only found within Neurospora. These results shed light on the diversity of genes capable of causing meiotic drive, their origin and evolution, and their interaction with the host genome.

scholarly journals Gene Sequencing and Phylogenetic Analysis: Powerful Tools for an Improved Diagnosis of Fish Mycobacteriosis Caused by Mycobacterium fortuitum Group Members

2021 ◽  
Vol 9 (4) ◽  
pp. 797
Author(s):  
Davide Mugetti ◽  
Mattia Tomasoni ◽  
Paolo Pastorino ◽  
Giuseppe Esposito ◽  
Vasco Menconi ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Gene Sequencing ◽  
Diagnostic Techniques ◽  
Individual Species ◽  
Identification System ◽  
Mycobacterium Fortuitum ◽  
Biochemical Tests ◽  
Species Determination ◽  
Gene Encoding ◽  
The Individual

The Mycobacterium fortuitum group (MFG) consists of about 15 species of fast-growing nontuberculous mycobacteria (NTM). These globally distributed microorganisms can cause diseases in humans and animals, especially fish. The increase in the number of species belonging to MFG and the diagnostic techniques panel do not allow to clarify their real clinical significance. In this study, biomolecular techniques were adopted for species determination of 130 isolates derived from fish initially identified through biochemical tests as NTM belonging to MFG. Specifically, gene sequencing and phylogenetic analysis were used based on a fragment of the gene encoding the 65 KDa heat shock protein (hsp65). The analyzes made it possible to confirm that all the isolates belong to MFG, allowing to identify the strains at species level. Phylogenetic analysis substantially confirmed what was obtained by gene sequencing, except for six strains; this is probably due to the sequences present in NCBI database. Although the methodology used cannot represent a univocal identification system, this study has allowed us to evaluate its effectiveness as regards the species of MFG. Future studies will be necessary to apply these methods with other gene fragments and to clarify the real pathogenic significance of the individual species of this group of microorganisms.

scholarly journals Molecular Phylogenetic Analysis of the AIG Family in Vertebrates

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1190
Author(s):  
Yuqi Huang ◽  
Minghao Sun ◽  
Lenan Zhuang ◽  
Jin He
Keyword(s):  
Phylogenetic Analysis ◽  
Gene Family ◽  
Functional Characterization ◽  
Vertebrate Evolution ◽  
Molecular Phylogenetic Analysis ◽  
Whole Genome Duplications ◽  
Genome Duplications ◽  
Molecular Phylogenetic ◽  
Duplication Events ◽  
Inducible Genes

Androgen-inducible genes (AIGs), which can be regulated by androgen level, constitute a group of genes characterized by the presence of the AIG/FAR-17a domain in its protein sequence. Previous studies on AIGs demonstrated that one member of the gene family, AIG1, is involved in many biological processes in cancer cell lines and that ADTRP is associated with cardiovascular diseases. It has been shown that the numbers of AIG paralogs in humans, mice, and zebrafish are 2, 2, and 3, respectively, indicating possible gene duplication events during vertebrate evolution. Therefore, classifying subgroups of AIGs and identifying the homologs of each AIG member are important to characterize this novel gene family further. In this study, vertebrate AIGs were phylogenetically grouped into three major clades, ADTRP, AIG1, and AIG-L, with AIG-L also evident in an outgroup consisting of invertebrsate species. In this case, AIG-L, as the ancestral AIG, gave rise to ADTRP and AIG1 after two rounds of whole-genome duplications during vertebrate evolution. Then, the AIG family, which was exposed to purifying forces during evolution, lost or gained some of its members in some species. For example, in eutherians, Neognathae, and Percomorphaceae, AIG-L was lost; in contrast, Salmonidae and Cyprinidae acquired additional AIG copies. In conclusion, this study provides a comprehensive molecular phylogenetic analysis of vertebrate AIGs, which can be employed for future functional characterization of AIGs.

scholarly journals Evolutionary dynamics of spore killers.

Genetics ◽  
1993 ◽  
Vol 135 (3) ◽  
pp. 923-930 ◽  
Author(s):  
M J Nauta ◽  
R F Hoekstra
Keyword(s):  
Life Cycle ◽  
Segregation Distortion ◽  
Population Genetic ◽  
Field Data ◽  
Evolutionary Dynamics ◽  
Natural Populations ◽  
Additional Advantage ◽  
Genetic Modeling ◽  
Spore Killing ◽  
Ascospore Formation

Abstract Spore killing in ascomycetes is a special form of segregation distortion. When a strain with the Killer genotype is crossed to a Sensitive type, spore killing is expressed by asci with only half the number of ascospores as usual, all surviving ascospores being of the Killer type. Using population genetic modeling, this paper explores conditions for invasion of Spore killers and for polymorphism of Killers, Sensitives and Resistants (which neither kill, nor get killed), as found in natural populations. The models show that a population with only Killers and Sensitives can never be stable. The invasion of Killers and stable polymorphism only occur if Killers have some additional advantage during the process of spore killing. This may be due to the effects of local sib competition or some kind of "heterozygous" advantage in the stage of ascospore formation or in the short diploid stage of the life cycle. This form of segregation distortion appears to be essentially different from other, well-investigated forms, and more field data are needed for a better understanding of spore killing.

scholarly journals Sex Chromosome Meiotic Drive in Stalk-Eyed Flies

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1169-1180 ◽  
Author(s):  
Daven C Presgraves ◽  
Emily Severance ◽  
Gerald S Willrinson
Keyword(s):  
Sex Ratio ◽  
Sex Chromosome ◽  
Sex Ratios ◽  
Natural Populations ◽  
Meiotic Drive ◽  
Operational Sex Ratio ◽  
Genetic Modifiers ◽  
Ratio Distortion ◽  
The Impact ◽  
Sex Ratio Distortion

Meiotically driven sex chromosomes can quickly spread to fixation and cause population extinction unless balanced by selection or suppressed by genetic modifiers. We report results of genetic analyses that demonstrate that extreme female-biased sex ratios in two sister species of stalk-eyed flies, Cyrtodiopsis dalmanni and C. whitei, are due to a meiotic drive element on the X chromosome (Xd). Relatively high frequencies of Xd in C. dalmanni and C. whitei (13–17% and 29%, respectively) cause female-biased sex ratios in natural populations of both species. Sex ratio distortion is associated with spermatid degeneration in male carriers of Xd. Variation in sex ratios is caused by Y-linked and autosomal factors that decrease the intensity of meiotic drive. Y-linked polymorphism for resistance to drive exists in C. dalmanni in which a resistant Y chromosome reduces the intensity and reverses the direction of meiotic drive. When paired with Xd, modifying Y chromosomes (Ym) cause the transmission of predominantly Y-bearing sperm, and on average, production of 63% male progeny. The absence of sex ratio distortion in closely related monomorphic outgroup species suggests that this meiotic drive system may predate the origin of C. whitei and C. dalmanni. We discuss factors likely to be involved in the persistence of these sex-linked polymorphisms and consider the impact of Xd on the operational sex ratio and the intensity of sexual selection in these extremely sexually dimorphic flies.

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