Loss of heterozygosity drives adaptation in hybrid yeast
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA376031 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:CGH arrays for Smukowski Heil, et al MBE 2017. Hybridization is often considered maladaptive, but sometimes hybrids can invade new ecological niches and adapt to novel or stressful environments better than their parents. The genomic changes that occur following hybridization that facilitate genome resolution and/or adaptation are not well understood. Here, we address these questions using experimental evolution of de novo interspecific hybrid yeast Saccharomyces cerevisiae x Saccharomyces uvarum and their parentals. We evolved these strains in nutrient limited conditions for hundreds of generations and sequenced the resulting cultures to identify genomic changes. Analysis of 16 hybrid clones and 16 parental clones identified numerous point mutations, copy number changes, and loss of heterozygosity events, including species biased amplification of nutrient transporters. We focused on a particularly interesting example, in which we saw repeated loss of heterozygosity at the high affinity phosphate transporter gene PHO84 in both intra- and interspecific hybrids. Using allele replacement methods, we tested the fitness of different alleles in hybrid and S. cerevisiae strain backgrounds and found that the loss of heterozygosity is indeed the result of selection on one allele over the other in both S. cerevisiae and the hybrids. This is an example where hybrid genome resolution is driven by positive selection on existing heterozygosity, and demonstrates that even infrequent outcrossing may have lasting impacts on adaptation.
2017-02-21 | GSE95086 | GEO
Project description:Hybridization is often considered maladaptive, but sometimes hybrids can invade new ecological niches and adapt to novel or stressful environments better than their parents. The genomic changes that occur following hybridization that facilitate genome resolution and/or adaptation are not well understood. Here, we examine hybrid genome evolution using experimental evolution of de novo interspecific hybrid yeast Saccharomyces cerevisiae × Saccharomyces uvarum and their parentals. We evolved these strains in nutrient-limited conditions for hundreds of generations and sequenced the resulting cultures identifying numerous point mutations, copy number changes, and loss of heterozygosity (LOH) events, including species-biased amplification of nutrient transporters. We focused on a particularly interesting example, in which we saw repeated LOH at the high-affinity phosphate transporter gene PHO84 in both intra- and interspecific hybrids. Using allele replacement methods, we tested the fitness of different alleles in hybrid and S. cerevisiae strain backgrounds and found that the LOH is indeed the result of selection on one allele over the other in both S. cerevisiae and the hybrids. This is an example where hybrid genome resolution is driven by positive selection on existing heterozygosity and demonstrates that even infrequent outcrossing may have lasting impacts on adaptation.
| S-EPMC5455960 | biostudies-literature
Project description:BackgroundHybrids are chimeric organisms with highly plastic heterozygous genomes that may confer unique traits enabling the adaptation to new environments. However, most evolutionary theory frameworks predict that the high levels of genetic heterozygosity present in hybrids from divergent parents are likely to result in numerous deleterious epistatic interactions. Under this scenario, selection is expected to favor recombination events resulting in loss of heterozygosity (LOH) affecting genes involved in such negative interactions. Nevertheless, it is so far unknown whether this phenomenon actually drives genomic evolution in natural populations of hybrids. To determine the balance between selection and drift in the evolution of LOH patterns in natural yeast hybrids, we analyzed the genomic sequences from fifty-five hybrid strains of the pathogenic yeasts Candida orthopsilosis and Candida metapsilosis, which derived from at least six distinct natural hybridization events.ResultsWe found that, although LOH patterns in independent hybrid clades share some level of convergence that would not be expected from random occurrence, there is an apparent lack of strong functional selection. Moreover, while mitosis is associated with a limited number of inter-homeologous chromosome recombinations in these genomes, induced DNA breaks seem to increase the LOH rate. We also found that LOH does not accumulate linearly with time in these hybrids. Furthermore, some C. orthopsilosis hybrids present LOH patterns compatible with footprints of meiotic recombination. These meiotic-like patterns are at odds with a lack of evidence of sexual recombination and with our inability to experimentally induce sporulation in these hybrids.ConclusionsOur results suggest that genetic drift is the prevailing force shaping LOH patterns in these hybrid genomes. Moreover, the observed LOH patterns suggest that these are likely not the result of continuous accumulation of sporadic events-as expected by mitotic repair of rare chromosomal breaks-but rather of acute episodes involving many LOH events in a short period of time.
| S-EPMC10173528 | biostudies-literature
Project description:This experiment is the analysis of the transcriptomes of several hybrid yeast strains obtained by crossing natural (from wine) isolates of S. cerevisiae and S. uvarum. All isolations have been done from hybrid strains growing in exponential phase in YPD. Keywords: Strain comparison
2008-07-15 | GSE9888 | GEO
Project description:Loss of MLL3 facilitates mesenchymal cells to acquire a mesenchymal/epithelial hybrid state during metastatic colonization. The MET occurring in distant metastases is likely driven by stromal signals in the metastatic niche. One signaling pathway that promotes the MET is the activation of protein kinase A (PKA). The MET hybrid cells can be identified as CD44+CD104+/high. Forskolin treatment generated significantly more CD44+CD104high hybrid cells in MLL3-mutant cells than the WT MDA-MB-231 cells. While both WT and MLL3-mutant CD44+CD104high hybrid EMT cells showed significantly increased lung metastatic ability than the counterpart CD44+CD104low mesenchymal cells, the MLL3-mutant hybrid cells showed a much greater metastasis-initiating ability than the WT hybrid cells. Here we reported the gene expression profiles of CD44+CD104high E/M hybird and CD44+CD104-/low mesenchymal cell populations sorted from Foskolin-treated, MLL3-null MDA-MB-231 cells.
2022-10-07 | GSE171444 | GEO
Project description:Phenotypic plasticity associated with the hybrid epithelial-mesenchymal transition (EMT) state is crucial to metastatic seeding and outgrowth. We showed that deletion of the epigenetic regulator MLL3, a tumor suppressor frequently altered in human cancer, promoted the acquisition of the hybrid EMT state in both epithelial and mesenchymal breast cancer cells by facilitating EMT and MET, distinct from other known EMT regulators mediating unidirectional changes. MLL3 deletion greatly increased metastasis by enhancing metastatic outgrowth during colonization. Mechanistically, MLL3 loss led to IFNγ signaling upregulation, which contributes to the induction of hybrid EMT cells and the enhanced metastatic capacity.
2022-10-07 | GSE206658 | GEO
Project description:Phenotypic plasticity associated with the hybrid epithelial-mesenchymal transition (EMT) state is crucial to metastatic seeding and outgrowth. However, the mechanisms controlling the induction of hybrid EMT remain poorly defined. We showed that deletion of the epigenetic regulator MLL3, a tumor suppressor frequently altered in human cancer, promoted the acquisition of the hybrid EMT state in both epithelial and mesenchymal breast cancer cells by facilitating EMT and MET, distinct from other known EMT regulators mediating unidirectional changes. Consequently, MLL3 deletion greatly increased metastasis by enhancing metastatic outgrowth during colonization. Mechanistically, MLL3 loss led to IFNγ signaling upregulation, which contributes to the induction of hybrid EMT cells and the enhanced metastatic capacity.
2022-10-07 | GSE206656 | GEO
Project description:Loss of MLL3 facilitates mesenchymal cells to acquire a mesenchymal/epithelial hybrid state during metastatic colonization. The MET occurring in distant metastases is likely driven by stromal signals in the metastatic niche. One signaling pathway that promotes the MET is the activation of protein kinase A (PKA). The MET hybrid cells can be identified as CD44+CD104+/high. Forskolin treatment generated significantly more CD44+CD104high hybrid cells in MLL3-mutant cells than the WT MDA-MB-231 cells. While both WT and MLL3-mutant CD44+CD104high hybrid EMT cells showed significantly increased lung metastatic ability than the counterpart CD44+CD104low mesenchymal cells, the MLL3-mutant hybrid cells showed a much greater metastasis-initiating ability than the WT hybrid cells. Here we reported the gene expression profiles of CD44+CD104high E/M hybird and CD44+CD104-/low mesenchymal cell populations sorted from Foskolin-treated, WT MDA-MB-231 cells.
2022-10-07 | GSE206653 | GEO
Project description:Oncocytic variants of follicular thyroid carcinomas show a near-homozygous genome. Remarkably, homozygosity of chromosome 7 has never been observed which suggests that retention of heterozygosity is essential for cells. We hypothesized that cell survival genes are genetically imprinted on either of two copies of chromosome 7 which thwarts loss of heterozygosity at this chromosome in cancer cells. We identified 6 genes on chromosome 7 which demonstrated allele-specific expression. Subsequent knockdown of gene expression showed that CALCR, COPG2, GRB10, KLF14, MEST and PEG10 were essential for cancer cell survival resulting in reduced cell proliferation, G1-phase arrest and increased apoptosis. We propose that imprinted cell survival genes provide a genetic basis for retention of chromosome 7 heterozygosity in cancer cells.
2019-01-01 | GSE77804 | GEO
Project description:Phenotypic plasticity associated with the hybrid epithelial-mesenchymal transition (EMT) state is crucial to metastatic seeding and outgrowth. However, the mechanisms controlling the induction of hybrid EMT remain poorly defined. We showed that deletion of the epigenetic regulator MLL3, a tumor suppressor frequently altered in human cancer, promoted the acquisition of the hybrid EMT state in both epithelial and mesenchymal breast cancer cells by facilitating EMT and MET, distinct from other known EMT regulators mediating unidirectional changes. Consequently, MLL3 deletion greatly increased metastasis by enhancing metastatic outgrowth during colonization. Mechanistically, MLL3 loss led to IFNγ signaling upregulation, which contributes to the induction of hybrid EMT cells and the enhanced metastatic capacity.
2022-10-07 | GSE206657 | GEO