scholarly journals Cytoplasmic-nuclear incompatibility between wild-isolates of Caenorhabditis nouraguensis

2016 ◽  
Author(s):  
Piero Lamelza ◽  
Michael Ailion
Keyword(s):  
Genetic Basis ◽  
Hybrid Sterility ◽  
Reproductive Barrier ◽  
Reproductive Barriers ◽  
Cytoplasmic Factor ◽  
Hybrid Inviability ◽  
Hybrid Incompatibility ◽  
Endosymbiotic Bacteria ◽  
Nuclear Locus ◽  
Shed Light

ABSTRACTHow species arise is a fundamental question in biology. Species can be defined as populations of interbreeding individuals that are reproductively isolated from other such populations. Therefore, understanding how reproductive barriers evolve between populations is essential for understanding the process of speciation. Hybrid incompatibility (e.g. hybrid sterility and lethality) is a common and strong reproductive barrier in nature, but few studies have molecularly identified its genetic basis. Here we report a lethal incompatibility between two wild-isolates of the nematode Caenorhabditis nouraguensis. Hybrid inviability results from the incompatibility between a maternally inherited cytoplasmic factor from each strain and a recessive nuclear locus from the other. We have excluded the possibility that maternally inherited endosymbiotic bacteria cause the incompatibility by treating both strains with tetracycline and show that hybrid death is unaffected. Furthermore, cytoplasmic-nuclear incompatibility commonly occurs between other wild-isolates, indicating that this is a significant reproductive barrier within C. nouraguensis. We hypothesize that the maternally inherited cytoplasmic factor is the mitochondrial genome and that mitochondrial dysfunction underlies hybrid death. This system has the potential to shed light on the dynamics of divergent mitochondrial-nuclear coevolution and its role in promoting speciation.

scholarly journals Patterns of reproductive isolation in a haplodiploid mite, Amphitetranychus viennensis: prezygotic isolation, hybrid inviability and hybrid sterility

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yukie Sato ◽  
Satoshi Fujiwara ◽  
Martijn Egas ◽  
Tomoko Matsuda ◽  
Tetsuo Gotoh
Keyword(s):  
Reproductive Isolation ◽  
Genetic Distance ◽  
Spider Mite ◽  
Hybrid Sterility ◽  
Fertilization Rate ◽  
Spider Mites ◽  
Reproductive Barriers ◽  
Hybrid Female ◽  
Hybrid Inviability ◽  
Prezygotic Isolation

Abstract Background Evolution of reproductive isolation is an important process, generating biodiversity and driving speciation. To better understand this process, it is necessary to investigate factors underlying reproductive isolation through various approaches but also in various taxa. Previous studies, mainly focusing on diploid animals, supported the prevalent view that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection by showing a positive relationship between the degree of reproductive isolation and genetic distance. Haplodiploid animals are expected to generate additional insight into speciation, but few studies investigated the prevalent view in haplodiploid animals. In this study, we investigate whether the relationship also holds in a haplodiploid spider mite, Amphitetranychus viennensis (Zacher). Results We sampled seven populations of the mite in the Palaearctic region, measured their genetic distance (mtDNA) and carried out cross experiments with all combinations. We analyzed how lack of fertilization rate (as measure of prezygotic isolation) as well as hybrid inviability and hybrid sterility (as measures of postzygotic isolation) varies with genetic distance. We found that the degree of reproductive isolation varies among cross combinations, and that all three measures of reproductive isolation have a positive relationship with genetic distance. Based on the mtDNA marker, lack of fertilization rate, hybrid female inviability and hybrid female sterility were estimated to be nearly complete (99.0–99.9% barrier) at genetic distances of 0.475–0.657, 0.150–0.209 and 0.145–0.210, respectively. Besides, we found asymmetries in reproductive isolation. Conclusions The prevalent view on the evolution of reproductive barriers is supported in the haplodiploid spider mite we studied here. According to the estimated minimum genetic distance for total reproductive isolation in parent population crosses in this study and previous work, a genetic distance of 0.15–0.21 in mtDNA (COI) appears required for speciation in spider mites. Variations and asymmetries in the degree of reproductive isolation highlight the importance of reinforcement of prezygotic reproductive isolation through incompatibility and the importance of cytonuclear interactions for reproductive isolation in haplodiploid spider mites.

scholarly journals When acting as a reproductive barrier for sympatric speciation, hybrid sterility can only be primary

2019 ◽  
Vol 128 (4) ◽  
pp. 779-788 ◽  
Author(s):  
Donald R Forsdyke
Keyword(s):  
Hybrid Sterility ◽  
Sympatric Speciation ◽  
The Other ◽  
Reproductive Barriers ◽  
Evolutionary Time ◽  
Hybrid Inviability ◽  
Prezygotic Isolation ◽  
Microscopic Scale ◽  
A New Species

Abstract Animal gametes unite to form a zygote that develops into an adult with gonads that, in turn, produce gametes. Interruption of this germinal cycle by prezygotic or postzygotic reproductive barriers can result in two cycles, each with the potential to evolve into a new species. When the speciation process is complete, members of each species are fully reproductively isolated from those of the other. During speciation a primary barrier may be supported and eventually superceded by a later-appearing secondary barrier. For those holding certain cases of prezygotic isolation to be primary (e.g. elephant cannot copulate with mouse), the onus is to show that they had not been preceded over evolutionary time by periods of postzygotic hybrid inviability (genically determined) or sterility (genically or chromosomally determined). Likewise, the onus is upon those holding cases of hybrid inviability to be primary (e.g. Dobzhansky–Muller epistatic incompatibilities) to show that they had not been preceded by periods, however brief, of hybrid sterility. The latter, when acting as a sympatric barrier causing reproductive isolation, can only be primary. In many cases, hybrid sterility may result from incompatibilities between parental chromosomes that attempt to pair during meiosis in the gonad of their offspring (Winge-Crowther-Bateson incompatibilities). While such incompatibilities have long been observed on a microscopic scale, there is growing evidence for a role of dispersed finer DNA sequence differences (i.e. in base k-mers).

scholarly journals Patterns of reproductive isolation in a haplodiploid mite, Amphitetranychus viennensis: prezygotic isolation, hybrid inviability and hybrid sterility

2021 ◽  
Author(s):  
Yukie Sato ◽  
Satoshi Fujiwara ◽  
Martijn Egas ◽  
Tomoko Matsuda ◽  
Tetsuo Gotoh
Keyword(s):  
Reproductive Isolation ◽  
Genetic Distance ◽  
Spider Mite ◽  
Hybrid Sterility ◽  
Fertilization Rate ◽  
Spider Mites ◽  
Reproductive Barriers ◽  
Hybrid Female ◽  
Hybrid Inviability ◽  
Prezygotic Isolation

Abstract Background Evolution of reproductive isolation is an important process, generating biodiversity and driving speciation. To better understand this process, it is necessary to investigate factors underlying reproductive isolation through various approaches but also in various taxa. Previous studies, mainly focusing on diploid animals, supported the prevalent view that reproductive barriers evolve gradually as a by-product of genetic changes accumulated by natural selection by showing a positive relationship between the degree of reproductive isolation and genetic distance. Haplodiploid animals are expected to generate additional insight into speciation, but few studies investigated the prevalent view in haplodiploid animals. In this study, we investigate whether the relationship also holds in a haplodiploid spider mite, Amphitetranychus viennensis (Zacher). Results We sampled seven populations of the mite in the Palaearctic region, measured their genetic distance (mtDNA) and carried out cross experiments with all combinations. We analyzed how lack of fertilization rate (as measure of prezygotic isolation) as well as hybrid inviability and hybrid sterility (as measures of postzygotic isolation) varies with genetic distance. We found that the degree of reproductive isolation varies among cross combinations, and that all three measures of reproductive isolation have a positive relationship with genetic distance. Based on the mtDNA marker, lack of fertilization rate, hybrid female inviability and hybrid female sterility were estimated to be nearly complete (99.0–99.9% barrier) at genetic distances of 0.475–0.657, 0.150–0.209 and 0.138–0.204, respectively. Conclusions The prevalent view on the evolution of reproductive barriers is supported in the haplodiploid spider mite we studied here. According to the estimated minimum genetic distance for total reproductive isolation in parent population crosses in this and previous studies, a genetic distance of 0.152–0.210 in mtDNA (COI) appears required for speciation in spider mites. Due to a lack of hybrid males, we could not address Haldane’s rule, which can be extended to haplodiploids, even though we focused on a young diverging group of spider mites. Our results highlight the importance of cytonuclear interactions for reproductive isolation in haplodiploid spider mites.

HYBRID STERILITY AS A REPRODUCTIVE BARRIER ISOLATING THE TWO SUBSPECIES OF AEGILOPS GENICOLATA ROTH (GRAMINEAE)

1999 ◽  
Vol 47 (2) ◽  
pp. 89-95 ◽  
Author(s):  
Shoji Ohta
Keyword(s):  
Hybrid Sterility ◽  
Chromosomal Rearrangements ◽  
Reproductive Barrier ◽  
Reproductive Barriers ◽  
Polyploid Species ◽  
Negative Interaction ◽  
Aegilops Geniculata ◽  
Chromosome Differentiation ◽  
Infraspecific Taxa ◽  
Mother Cells

To detect possible reproductive barriers isolating the two subspecies of Aegilops geniculata, ssp. gibberosa was crossed with ssp. geniculata. The two subspecies differ significantly in shape of spikes, spikelet density on spikes, and number of awns on empty glumes. The F hybrids were intermediate in morphology and almost completely sterile. A chromatid bridge with a fragment was observed at first anaphase (AI) of meiosis in some pollen mother cells (PMCs) of the F1 hybrids. Though multivalents were formed at first metaphase (MI) in all the PMCs of the F1 hybrids, the frequency was not higher than that in the intra-subspecific hybrids of ssp. geniculata. These results suggest that the intraspecific sterility is not caused by a gross chromosome differentiation. The hybrid sterility, which is an effective reproductive barrier isolating the two subspecies, might be caused by negative interaction(s) between genes of the two subspecies, or by small chromosomal rearrangements not detectable from chromosome pairing configuration at MI. It is strongly proposed that the delineation of species and infraspecific taxa in the polyploid species of the genus Aegilops is worthy of reassessment from a biosystematic viewpoint.

THE EVOLUTIONARY HISTORY OF DROSOPHILA BUZZATII. XII. THE GENETIC BASIS OF STERILITY IN HYBRIDS BETWEEN D. BUZZATII AND ITS SIBLING D. SERIDO FROM ARGENTINA

Genetics ◽  
1986 ◽  
Vol 114 (3) ◽  
pp. 841-857
Author(s):  
Horacio Naveira ◽  
Antonio Fontdevila
Keyword(s):  
Evolutionary History ◽  
Genetic Basis ◽  
Hybrid Sterility ◽  
Polytene Chromosomes ◽  
Chromosome Segment ◽  
Minimum Size ◽  
Drosophila Buzzatii ◽  
History Of ◽  
Male Hybrid ◽  
Chromosome Segments

ABSTRACT The genetic basis of hybrid sterility has been investigated in backcross segmental hybrids between two sibling species, Drosophila buzzatii and D. serido. Asynapsis of homologous bands in hybrid polytene chromosomes has been used to identify the D. serido chromosome segments introgressed into the D. buzzatti genome. All the investigated chromosomes contain male sterility factors. For autosomes, sterility is produced when an introgressed D. serido chromosome segment, or combination of segments, reaches a minimum size. On the other hand, any introgressed X chromosome segment from D. serido, irrespective of its size, produces either male hybrid sterility or inviability.

Anomalous apetaly: localized character displacement in Ranunculus eschscholtzii

1979 ◽  
Vol 57 (20) ◽  
pp. 2097-2106 ◽  
Author(s):  
F. J. F. Fisher ◽  
A. Warner ◽  
E. M. Reimer
Keyword(s):  
Normal Form ◽  
Hybrid Sterility ◽  
Diploid Species ◽  
Character Displacement ◽  
Reproductive Barriers ◽  
Cascade Mountains ◽  
Rare Variation ◽  
High Rainfall ◽  
Pollen Vectors

Apetaly is usually a rare variation in populations of the widespread hexaploid alpine Ranunculus eschscholtzii Schlecht. In certain high rainfall sections of the western Cascade Mountains of Washington, where populations of the hexaploid have been found in mixed association with those of a diploid relative, R. suksdorfii (elsewhere ecologically well separated though sympatric), the apetalous condition almost completely replaces the normal form. Any petal-bearing flowers of the hexaploid attract the flying pollen vectors (mainly syrphids) which also visit the overwhelmingly more numerous diploid species. Any resulting hybrids between the two species are sterile. Apetalous flowers are avoided by the syrphid pollinators. These flowers, nevertheless, regularly produce full sets of viable fruits. This may be attributed to the regular foraging visits of large terrestrial ants. The apetalous condition of R. eschscholtzii appears to have replaced the normal form in the high rainfall areas because only it can continue to reproduce and maintain the species in the presence of R. suksdorfii and the syrphid pollinators. This regional intensification of reproductive barriers between species already genetically isolated by their difference in ploidy, and between which hybrids have zero fitness, is interpreted as a case of character displacement involving both competition for a resource (pollinators) and hybrid sterility.

scholarly journals Evolutionary Implications of Mechanistic Models of TE-Mediated Hybrid Incompatibility

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Dean M. Castillo ◽  
Leonie C. Moyle
Keyword(s):  
Mechanistic Models ◽  
Hybrid Inviability ◽  
Hybrid Incompatibility ◽  
Mode Of Reproduction ◽  
Geographical Structure ◽  
New Models

New models of TE repression in plants (specifically Arabidopsis) have suggested specific mechanisms by which TE misregulation in hybrids might result in the expression of hybrid inviability. If true, these models suggest as yet undescribed consequences for (1) mechanistic connections between hybrid problems expressed at different postzygotic stages (e.g., inviability versus sterility), (2) the predicted strength, stage, and direction of isolation between diverging lineages that differ in TE activity, and (3) the association between species attributes that influence TE dynamics (e.g., mode of reproduction, geographical structure) and the rate at which they could accumulate incompatibilities. In this paper, we explore these implications and outline future empirical directions for generating data necessary to evaluate them.

scholarly journals Flower morphological diversity of cinnamon (Cinnamomum verum Presl) in Matara District, Sri Lanka

2018 ◽  
Vol 3 (1) ◽  
pp. 236-244 ◽  
Author(s):  
Rumana Azad ◽  
K.L. Wasantha Kumara ◽  
Gamini Senanayake ◽  
R.A.A.K. Ranawaka ◽  
D.K.N.G Pushpakumara ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Morphological Diversity ◽  
Type A ◽  
Tube Length ◽  
Type B ◽  
Inflorescence Morphology ◽  
Single Flower ◽  
Peduncle Length ◽  
Shed Light

Abstract The cinnamon flowers exhibit protogynous dichogamy with 2 flower types “Type A” and “Type B” which first flowers during morning and evening respectively. This floral cycle causes a temporal barrier to the maintenance of elite breeding material and for hybridization with desired parents. Determination of variation in flower and inflorescence morphology can shed light on functional diversity in “Type A” and “Type B” flowers. In order to study these variations, a survey of cultivated cinnamon lands and wild habitats was conducted in fifteen locations in the Matara district. Peduncle length (PDL), flower length (FL), flower width (FW), and floral tube length (FTL) varied among cinnamon accessions collected. The variation in tepal shape was distinct: the two whorls of tepals of a single flower exhibited two shapes. The current investigation of differences in inflorescence, floral morphology and floral abnormalities of Cinnamomum verum provides information about their diversity, and recommends molecular analysis to further determine the genetic basis of two flower types in progynous dichogamy.

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