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PROVIDER: PRJNA1003462 | ENA |
REPOSITORIES: ENA
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Project description:Genomic patterns and mechanisms of postzygotic reproductive isolation between closely related monkeyflower species
| PRJNA936857 | ENA
Project description:Hybridization of eggs and sperm from closely related species can give rise to genetic diversity, or can lead to embryo inviability due to incompatibility. Although central to evolution, the cellular and molecular mechanisms underlying postzygotic barriers that drive reproductive isolation and speciation remain largely unknown. Species of the African Clawed frog Xenopus provide an ideal system to study hybridization and genome evolution. Xenopus laevis is an allotetraploid with 36 chromosomes that arose through interspecific hybridization of diploid progenitors, whereas Xenopus tropicalis is a diploid with 20 chromosomes that diverged from a common ancestor ~48 million years ago. Differences in genome size between the two species are accompanied by organism size differences, and size scaling of the egg and subcellular structures such as nuclei and spindles formed in egg extracts. Nevertheless, early development transcriptional programs, gene expression patterns, and protein sequences are generally conserved. Interestingly, whereas the hybrid produced when X. laevis eggs are fertilized by X. tropicalis sperm (le×ts) is viable, the reverse hybrid (te×ls) dies prior to gastrulation. Here, we applied cell biological tools and high-throughput methods to study the mechanisms underlying hybrid inviability. We reveal that two specific X. laevis chromosomes are incompatible with the X. tropicalis cytoplasm and are mis-segregated during mitosis, leading to unbalanced gene expression at the maternal to zygotic transition, followed by cell-autonomous catastrophic embryo death.
2017-11-01 | GSE106157 | GEO
Project description:We use closely-related Drosophila species to understand mechanosensation and how hearing as a form of mechanosensation drives reproductive isolation and evolution. In particular, we performed RNA-seq to obtain the Johnston's Organ transcriptomes of six closely-related Drosophila species, namely, D.melanogaster, D.yakuba, D.pseudoobscura and D.persimilis. Application of the Ornstein-Uhlenbeck model identified gene expression changes between the species' auditory structures. Motif discovery ( i-cisTarget and iRegulon) in differentially expressed genes in the oobscura group and melanogaster group on these transcriptomes identified thetranscription factor Hr39 as important for auditory differences among species. Hr39 is a nuclear hormone receptor important in song production and spermathecae development. Futher functional analyses Hr39 and many of its downstream targets are expressed in Johnston's Organ neurons. Hr39 mutants show sexually dimorphic defects in auditory mechanics and compound action potentials. These results indicate that Hr39 and its downstream regulon have a key role in Drosophila courtship behavior as a mechanism of reproductive isolation and evolution.
2020-07-05 | GSE100837 | GEO
Project description:Hybrid sterility is a major form of postzygotic reproductive isolation, which is a widespread phenomenon in plants. Hybrids between two subspecies of the Asian cultivated rice (Oryza sativa L.), indica and japonica, are usually highly sterile. A killer-protector system composed of three closely linked genes, ORF3, ORF4 and ORF5 at the S5 locus, has been unveiled to regulate hybrid female fertility. We performed transcriptomic analysis of wild type Balilla, sterile BalillaORF5+ (Balilla with a transformed ORF5+) and fertility-restored BalillaORF3+ORF5+ (Balilla with a transformed ORF3+ and a transformed ORF5+) at S1 (before meiosis), S2 (during meiosis) and S3 (after meiosis) respectively. By comparing the differentially expressed genes in different comparisons, we proposed a model for the mechanisms of the S5 mediated hybrid sterility.
2017-06-01 | GSE95200 | GEO
Project description:Reproductive isolation and introgression between sympatric Mimulus species
| PRJNA316724 | ENA
Project description:Fertility depends, in part, on interactions between male and female reproductive proteins inside the female reproductive tract (FRT) that mediate postmating changes in female behavior, morphology, and physiology. Coevolution between interacting proteins within species may drive reproductive incompatibilities between species, yet the mechanisms underlying postmating-prezygotic isolating barriers remain poorly resolved. Here, we used quantitative proteomics in sibling Drosophila species to investigate the molecular composition of the FRT environment and its role in mediating species-specific postmating responses. We found that (1) FRT proteomes in D. simulans and D. mauritiana virgin females express unique combinations of secreted proteins and are enriched for distinct functional categories, (2) mating induces substantial changes to the FRT proteome in D. mauritiana but not in D. simulans, and (3) the D. simulans FRT proteome exhibits limited postmating changes irrespective of whether females mate with conspecific or heterospecific males, suggesting an active female role in mediating reproductive interactions. Our study suggests that divergence in the FRT extracellular environment and postmating response contribute to previously described patterns of postmating-prezygotic isolation and the maintenance of species boundaries.
2020-06-25 | PXD017708 | Pride
Project description:Understanding the conditions that promote the evolution of reproductive isolation, and thus speciation. Here we empirically test some of the key predictions of speciation theory (Coyne 2004; Kohn 2005) by experimentally evolving the initial stages of speciation in yeast. After allowing replicate populations to adapt to two divergent environments, we observed the consistent, de novo evolution of two forms of postzygotic isolation: reduced rate of mitotic reproduction and reduced efficiency of meiotic reproduction. In general, divergent selection resulted in greater reproductive isolation than parallel selection, as predicted by ecological speciation theory. Our experimental system allowed for the first controlled comparison of the relative importance of ecological and genetic mechanisms of isolation, and the novel ability to quantify the effects of antagonistic epistasis. For mitotic reproduction, hybrid inferiority was conditional upon the selective environments and was both ecological and genetic in basis. In contrast, isolation associated with meiotic reproduction was unconditional and was caused solely by genetic mechanisms. Overall, our results show that adaption to divergent environments promotes the evolution of isolation through antagonistic epistasis, providing evidence of a plausible common avenue to speciation and adaptive radiation in nature (Schluter 2000,2001: Funk 2006) Keywords: Speciation, antagonistic epistasis, divergent adaptation
2007-06-21 | GSE6870 | GEO
Project description:The piRNA pathway is an adaptive mechanism for maintaining the stability of the genome by repression selfish genomic elements such as transposons. As a host defense mechanism the piRNA pathway is rapidly evolving with different sets of piRNA silencing different targets in closely-related species. In male germline of D.melanogaster, repression of Stellate genes by piRNA generated from Supressor of Stellate, Su(Ste), locus is required for male fertility, but both Su(Ste) piRNA and their targets are absent in other Drosophila species. Here we showed that D.melanogaster genome contain non-coding genomic repeats that have sequence similarity to vasa, protein-coding host gene essential for germline development. In male germline Vasa Related (Varel) repeats produce abundant piRNA that are anti-sense to vasa, however, vasa mRNA escape silencing due to imperfect complementarity between piRNA and vasa sequences. Unexpectedly, we found that Varel piRNA of D.melanogaster target vasa of closely related D. mauritana species in interspecies hybrids. The same hybrids show derepression of harmful Stellate locus due to the absence of Su(Ste) piRNA. Thus, the piRNA pathway contributes to the reproductive isolation between Drosophila species, causing hybrid male sterility via misregulation of two different host factors.
2019-02-19 | GSE120802 | GEO