scholarly journals Hybrid incompatibility caused by an epiallele

2017 ◽  
Vol 114 (14) ◽  
pp. 3702-3707 ◽  
Author(s):  
Todd Blevins ◽  
Jing Wang ◽  
David Pflieger ◽  
Frédéric Pontvianne ◽  
Craig S. Pikaard
Keyword(s):  
Epigenetic Variation ◽  
Hybrid Progeny ◽  
Histone Deacetylase 6 ◽  
Hybrid Lethality ◽  
Histidine Biosynthesis ◽  
Hybrid Incompatibility ◽  
Cytosine Methyltransferase ◽  
Biosynthesis Gene ◽  
Deleterious Gene ◽  
Epigenetic Phenomenon

Hybrid incompatibility resulting from deleterious gene combinations is thought to be an important step toward reproductive isolation and speciation. Here, we demonstrate involvement of a silent epiallele in hybrid incompatibility. In Arabidopsis thaliana accession Cvi-0, one of the two copies of a duplicated histidine biosynthesis gene, HISN6A, is mutated, making HISN6B essential. In contrast, in accession Col-0, HISN6A is essential because HISN6B is not expressed. Owing to these differences, Cvi-0 × Col-0 hybrid progeny that are homozygous for both Cvi-0 HISN6A and Col-0 HISN6B do not survive. We show that HISN6B of Col-0 is not a defective pseudogene, but a stably silenced epiallele. Mutating HISTONE DEACETYLASE 6 (HDA6), or the cytosine methyltransferase genes MET1 or CMT3, erases HISN6B's silent locus identity, reanimating the gene to circumvent hisn6a lethality and hybrid incompatibility. These results show that HISN6-dependent hybrid lethality is a revertible epigenetic phenomenon and provide additional evidence that epigenetic variation has the potential to limit gene flow between diverging populations of a species.

scholarly journals Hybrid incompatibility caused by an epiallele

2017 ◽  
Author(s):  
Todd Blevins ◽  
Jing Wang ◽  
David Pflieger ◽  
Frédéric Pontvianne ◽  
Craig S. Pikaard
Keyword(s):  
Arabidopsis Thaliana ◽  
Gene Flow ◽  
Reproductive Isolation ◽  
Epigenetic Variation ◽  
Lethal Gene ◽  
Histone Deacetylase 6 ◽  
Hybrid Incompatibility ◽  
Epigenetic Gene Silencing ◽  
Deleterious Gene ◽  
Epigenetic Phenomenon

AbstractHybrid incompatibility resulting from deleterious gene combinations is thought to be an important step towards reproductive isolation and speciation. Here we demonstrate involvement of a silent epiallele in hybrid incompatibility. In Arabidopsis thaliana strain Col-0, one of the two copies of a duplicated histidine biosynthesis gene, HISN6B is not expressed, for reasons that have been unclear, making its paralog, HISN6A essential. By contrast, in strain Cvi-0, HISN6B is essential because HISN6A is mutated. As a result of these differences, Cvi-0 × Col-0 hybrid progeny that are homozygous for both Col-0 HISN6B and Cvi-0 HISN6A do not survive. We show that HISN6B is not a defective pseudogene in the Col-0 strain, but a stably silenced epiallele. Mutating HISTONE DEACETYLASE 6 (HDA6) or the cytosine methyltransferase genes, MET1 or CMT3 erases HISN6B’s silent locus identity in Col-0, reanimating the gene such that hisn6a lethality and hybrid incompatibility are circumvented. These results show that HISN6-dependent hybrid lethality is a revertible epigenetic phenomenon and provide additional evidence that epigenetic variation has the potential to limit gene flow between diverging populations of a species.Significance statementDeleterious mutations in different copies of a duplicated gene pair have the potential to cause hybrid incompatibility between diverging subpopulations, contributing to reproductive isolation and speciation. This study demonstrates a case of epigenetic gene silencing, rather than pseudogene creation by mutation, contributing to a lethal gene combination upon hybridization of two strains of Arabidopsis thaliana. The findings provide direct evidence that naturally occurring epigenetic variation can contribute to incompatible hybrid genotypes, reducing gene flow between strains of the same species.

Two ATP phosphoribosyltransferase isozymes of Geobacter sulfurreducens contribute to growth in the presence or absence of histidine and under nitrogen fixation conditions

2011 ◽  
Vol 57 (7) ◽  
pp. 547-558 ◽  
Author(s):  
Muktak Aklujkar
Keyword(s):  
Gene Expression ◽  
Nitrogen Fixation ◽  
Mutational Analysis ◽  
Transcript Abundance ◽  
Geobacter Sulfurreducens ◽  
Growth Defect ◽  
Histidine Biosynthesis ◽  
Growth Defects ◽  
Biosynthesis Gene ◽  
Delayed Growth

Bacteria of the Geobacter clade possess two distinct ATP phosphoribosyltransferases encoded by hisGL and hisGS+hisZ to catalyze the first reaction of histidine biosynthesis. This very unusual redundancy was investigated by mutational analysis. The hisGL, hisGS, and hisZ genes of Geobacter sulfurreducens were deleted, effects on growth and histidine biosynthesis gene expression were evaluated, and deficiencies were complemented with plasmid-borne genes. Both hisGL and hisGS+hisZ encode functional ATP phosphoribosyltransferases. However, deletion of hisGL resulted in no growth defect, whereas deletion of hisGS delayed growth when histidine was not provided. Both deletions increased hisZ transcript abundance, and both ΔhisGS and ΔhisZ mutations increased hisGL transcript abundance. Growth with HisGL alone (due to deletion of either hisGS or hisZ) was better under nitrogen fixation conditions than when ammonium was provided. Deletion of hisZ caused growth defects under all conditions tested, with or without exogenous sources of histidine, with different patterns of histidine biosynthesis gene expression under each condition. Taken together, the data indicate that G. sulfurreducens depends primarily on the HisGSZ isozyme as an ATP phosphoribosyltransferase in histidine biosynthesis, and for other functions when histidine is available; however, HisGL also functions as ATP phosphoribosyltransferase, particularly during nitrogen fixation.

scholarly journals A Fine-Scale Genetic Analysis of Hybrid Incompatibilities in Drosophila

Genetics ◽  
2003 ◽  
Vol 163 (3) ◽  
pp. 955-972 ◽  
Author(s):  
Daven C Presgraves
Keyword(s):  
Functional Divergence ◽  
Genetic System ◽  
Small Region ◽  
Genetic Screen ◽  
Fine Scale ◽  
Hybrid Lethality ◽  
Epistatic Interactions ◽  
Hybrid Incompatibility ◽  
Fine Resolution ◽  
Species Hybrids

Abstract The sterility and inviability of species hybrids is thought to evolve by the accumulation of genes that cause generally recessive, incompatible epistatic interactions between species. Most analyses of the loci involved in such hybrid incompatibilities have suffered from low genetic resolution. Here I present a fine-resolution genetic screen that allows systematic counting, mapping, and characterizing of a large number of hybrid incompatibility loci in a model genetic system. Using small autosomal deletions from D. melanogaster and a hybrid rescue mutation from D. simulans, I measured the viability of hybrid males that are simultaneously hemizygous for a small region of the D. simulans autosomal genome and hemizygous for the D. melanogaster X chromosome. These hybrid males are exposed to the full effects of any recessive-recessive epistatic incompatibilities present in these regions. A screen of ∼70% of the D. simulans autosomal genome reveals 20 hybrid-lethal and 20 hybrid-semilethal regions that are incompatible with the D. melanogaster X. In further crosses, I confirm the epistatic nature of hybrid lethality by showing that all of the incompatibilities are rescued when the D. melanogaster X is replaced with a D. simulans X. Combined with information from previous studies, these results show that the number of recessive incompatibilities is approximately eightfold larger than the number of dominant ones. Finally, I estimate that a total of ∼191 hybrid-lethal incompatibilities separate D. melanogaster and D. simulans, indicating extensive functional divergence between these species’ genomes.

Diversity of the trifunctional histidine biosynthesis gene (his) in cerealPhaeosphaeriaspecies

Genome ◽  
2007 ◽  
Vol 50 (6) ◽  
pp. 595-609 ◽  
Author(s):  
Chih-Li Wang ◽  
Arkadiusz Malkus ◽  
Sabina M. Zuzga ◽  
Pi-Fang Linda Chang ◽  
Barry M. Cunfer ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Amino Acid ◽  
Meiotic Recombination ◽  
Pcr Amplification ◽  
Amino Acid Sequences ◽  
Histidine Biosynthesis ◽  
Leaf Blotch ◽  
Rates Of Evolution ◽  
Biosynthesis Gene ◽  
Histidinol Dehydrogenase

Phaeosphaeria species are important causal agents of Stagonospora leaf blotch diseases in cereals. In this study, the nucleotide sequence and deduced polypeptide of the trifunctional histidine biosynthesis gene (his) are used to investigate the phylogenetic relationships and provide molecular identification among cereal Phaeosphaeria species. The full-length sequences of the his gene were obtained by PCR amplification and compared among cereal Phaeosphaeria species. The coding sequence of the his gene in wheat-biotype P. nodorum (PN-w) was 2697 bp. The his genes in barley-biotype P. nodorum (PN-b), two P. avenaria f. sp. triticea isolates (homothallic Pat1 and Pat3), and Phaeosphaeria species from Polish rye and dallis grass were 2694 bp. The his gene in heterothallic isolate Pat2, however, was 2693 bp because the intron had one fewer base. In P. avenaria f. sp. avenaria (Paa), the his gene was only 2670 bp long. The differences in the size of the his gene contributed to the variation in amino acid sequences in the gap region located between the phosphoribosyl-ATP pyrophosphohydrolase and histidinol dehydrogenase sub-domains. Based on nucleotide and deduced amino acid sequences of the his gene, Pat1 was not closely related to either PN-w or the Paa clade. It appears that rates of evolution of the his gene were fast in cereal Phaeosphaeria species. The possible involvement of meiotic recombination in genetic diversity of the his gene in P. nodorum is discussed.

scholarly journals The Gossypium anomalum genome as a resource for cotton improvement and evolutionary analysis of hybrid incompatibility

2021 ◽  
Author(s):  
Corrinne E. Grover ◽  
Daojun Yuan ◽  
Mark A. Arick ◽  
Emma R. Miller ◽  
Guanjing Hu ◽  
...  
Keyword(s):  
Genome Sequencing ◽  
Stress Resistance ◽  
De Novo ◽  
Diploid Species ◽  
Evolutionary Analysis ◽  
Hybrid Lethality ◽  
Genome Sequences ◽  
High Quality ◽  
Hybrid Incompatibility ◽  
Modern Breeding

Cotton is an important crop that has been the beneficiary of multiple genome sequencing efforts, including diverse representatives of wild species for germplasm development. Gossypium anomalum is a wild African diploid species that harbors stress-resistance and fiber-related traits with potential application to modern breeding efforts. In addition, this species is a natural source of cytoplasmic male sterility and a resource for understanding hybrid lethality in the genus. Here we report a high-quality de novo genome assembly for G. anomalum and characterize this genome relative to existing genome sequences in cotton. In addition, we use the synthetic allopolyploids 2(A2D1) and 2(A2D3) to discover regions in the G. anomalum genome potentially involved in hybrid lethality, a possibility enabled by introgression of regions homologous to the D3 (G. davidsonii) lethality loci into the synthetic 2(A2D3) allopolyploid.

scholarly journals Mapping of Hybrid Incompatibility Loci in Nasonia

Genetics ◽  
1999 ◽  
Vol 153 (4) ◽  
pp. 1731-1741 ◽  
Author(s):  
Jürgen Gadau ◽  
Robert E Page ◽  
John H Werren
Keyword(s):  
Rapd Markers ◽  
Hybrid Breakdown ◽  
Hybrid Lethality ◽  
Hybrid Inviability ◽  
F1 Hybrid ◽  
Hybrid Incompatibility ◽  
Short Generation Time ◽  
Productive System ◽  
Zygotic Gene ◽  
Gene Complexes

Abstract According to theory, F2 hybrid breakdown (lethality or sterility) is due to incompatibilities between interacting genes of the different species (i.e., the breaking up of coadapted gene complexes). Detection of such incompatibilities is particularly straightforward in haplodiploid species, because virgin F1 hybrid females will produce haploid recombinant F2 males. This feature allows for screening of the complete genome for recessive genetic incompatibilities. Crosses were performed between Nasonia vitripennis (v) and its sibling species N. giraulti (g). First, a linkage map was produced using RAPD markers. RAPD markers showed an overall bias toward vitripennis alleles, a pattern not predicted by the basic two-interactor Dobzhansky-Muller model. Recovery patterns of visible markers were consistent with those of linked RAPD markers. If particular genetic interactions between two loci are causing hybrid lethality, then those genotypes should be underrepresented or absent among adult F2 males. Four sets of significant incompatibilities were detected by performing pairwise comparisons of markers on different chromosomes. Likely explanations for the observed patterns are maternal effect-zygotic gene incompatibilities or clustering of incompatibility loci. Due to the short generation time, advantages of haplodiploidy, and availability of markers, Nasonia promises to be a productive system for investigating the genetics of hybrid inviability.

scholarly journals A two-locus hybrid incompatibility is widespread, polymorphic, and active in natural populations of Mimulus

2018 ◽  
Author(s):  
Matthew P. Zuellig ◽  
Andrea L. Sweigart
Keyword(s):  
Gene Flow ◽  
General Pattern ◽  
Natural Populations ◽  
Reproductive Barriers ◽  
Hybrid Lethality ◽  
Closely Related Species ◽  
Hybrid Incompatibility ◽  
Genomic Divergence ◽  
Primary Driver ◽  
Incompatibility Alleles

ABSTRACTReproductive isolation, which is essential for the maintenance of species in sympatry, is often incomplete between closely related species. In these taxa, reproductive barriers must continue to evolve within species, without being degraded by ongoing gene flow. To better understand this dynamic, we investigated the frequency and distribution of incompatibility alleles at a two-locus, recessive-recessive hybrid lethality system between species of yellow monkeyflower (Mimulus guttatus and M. nasutus) that hybridize in nature. We found that M. guttatus typically carries hybrid lethality alleles at one locus (hl13) and M. nasutus typically carries hybrid lethality alleles at the other locus (hl14). As a result, most naturally formed hybrids will carry incompatible alleles at both loci, with the potential to express hybrid lethality in later generations. Despite this general pattern, we also discovered considerable polymorphism at both hl13 and hl14 within both Mimulus species. For M. guttatus, polymorphism at both loci even occurs within populations, meaning that incompatible allele pairings might also often arise through regular, intraspecific gene flow. By examining genetic variation linked to hl13 and hl14, we discovered that introgression from M. nasutus is a primary driver of this polymorphism within M. guttatus. Additionally, patterns of introgression at the two hybrid lethality loci suggest that natural selection acts to eliminate incompatible allele pairings, providing evidence that even weak reproductive barriers might promote genomic divergence between species.

scholarly journals The Gossypium anomalum genome as a resource for cotton improvement and evolutionary analysis of hybrid incompatibility

2021 ◽  
Author(s):  
Corrinne E Grover ◽  
Daojun Yuan ◽  
Mark A Arick ◽  
Emma R Miller ◽  
Guanjing Hu ◽  
...  
Keyword(s):  
Stress Resistance ◽  
De Novo ◽  
Diploid Species ◽  
Evolutionary Analysis ◽  
Hybrid Lethality ◽  
Genome Sequences ◽  
High Quality ◽  
De Novo Genome Assembly ◽  
Hybrid Incompatibility ◽  
Modern Breeding

Abstract Cotton is an important crop that has been the beneficiary of multiple genome sequencing efforts, including diverse representatives of wild species for germplasm development. Gossypium anomalum is a wild African diploid species that harbors stress-resistance and fiber-related traits with potential application to modern breeding efforts. In addition, this species is a natural source of cytoplasmic male sterility and a resource for understanding hybrid lethality in the genus. Here, we report a high-quality de novo genome assembly for G. anomalum and characterize this genome relative to existing genome sequences in cotton. In addition, we use the synthetic allopolyploids 2(A2D1) and 2(A2D3) to discover regions in the G. anomalum genome potentially involved in hybrid lethality, a possibility enabled by introgression of regions homologous to the D3 (Gossypium davidsonii) lethality loci into the synthetic 2(A2D3) allopolyploid.

The Microscopy of Compatibility and Incompatibility in Ulmus

1985 ◽  
Vol 43 ◽  
pp. 504-505
Author(s):  
B. L. Redmond ◽  
Christopher F. Bob
Keyword(s):  
Dutch Elm Disease ◽  
Economic Losses ◽  
Hybrid Progeny ◽  
Ulmus Pumila ◽  
Ulmus Americana ◽  
American Elm ◽  
Asian Species ◽  
Ulmus Parvifolia ◽  
Initial Appearance ◽  
Chinese Elm

The American Elm (Ulmus americana L.) has been plagued by Dutch Elm Disease (DED), a lethal disease caused by the fungus Ceratocystis ulmi (Buisman) c. Moreau. Since its initial appearance in North America around 1930, DED has wrought inexorable devastation on the American elm population, triggering both environmental and economic losses. In response to the havoc caused by the disease, many attempts have been made to hybridize U. americana with a few ornamentally less desirable, though highly DED resistant, Asian species (mainly the Siberian elm, Ulmus pumila L., and the Chinese elm Ulmus parvifolia Jacq.). The goal is to develop, through breeding efforts, hybrid progeny that display the ornamentally desirable characteristics of U. americana with the disease resistance of the Asian species. Unfortunately, however, all attempts to hybridize U. americana have been prevented by incompatibility. Only through a firm understanding of both compatibility and incompatibility will it be possible to circumvent the incompatibility and hence achieve hybridization.

Histone deacetylase 6– HDAC6– a new regulator of glucocorticoid receptor-mediated metabolic processes

2010 ◽  
Vol 5 (S 01) ◽  
Author(s):  
R Winkler ◽  
M Clemenz ◽  
M Bloch ◽  
A Foryst-Ludwig ◽  
C Böhm ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Histone Deacetylase ◽  
Histone Deacetylase 6 ◽  
Metabolic Processes
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