In exploring the evolutionary trajectories of both pathogenesis and karyotype dynamics in fungi, we conducted a large-scale comparative genomic analysis spanning the Cryptococcus genus, encompassing both global human fungal pathogens and nonpathogenic species, and related species from the sister genus Kwoniella. Chromosome-level genome assemblies were generated for multiple species, covering virtually all known diversity within these genera. Although Cryptococcus and Kwoniella have comparable genome sizes (about 19.
View Article and Find Full Text PDFA large-scale comparative genomic analysis was conducted for the global human fungal pathogens within the genus, compared to non-pathogenic species, and related species from the sister genus . Chromosome-level genome assemblies were generated for multiple species of both genera, resulting in a dataset encompassing virtually all of their known diversity. Although and have comparable genome sizes (about 19.
View Article and Find Full Text PDFFungi in the basidiomycete genus are the most prevalent eukaryotic microbes resident on the skin of human and other warm-blooded animals and have been implicated in skin diseases and systemic disorders. Analysis of genomes revealed that key adaptations to the skin microenvironment have a direct genomic basis, and the identification of mating/meiotic genes suggests a capacity to reproduce sexually, even though no sexual cycle has yet been observed. In contrast to other bipolar or tetrapolar basidiomycetes that have either two linked mating-type-determining () loci or two loci on separate chromosomes, in species studied thus far the two loci are arranged in a pseudobipolar configuration (linked on the same chromosome but capable of recombining).
View Article and Find Full Text PDFUnlabelled: Fungi in the basidiomycete genus are the most prevalent eukaryotic microbes resident on the skin of human and other warm-blooded animals and have been implicated in skin diseases and systemic disorders. Analysis of genomes revealed that key adaptations to the skin microenvironment have a direct genomic basis, and the identification of mating/meiotic genes suggests a capacity to reproduce sexually, even though no sexual cycle has yet been observed. In contrast to other bipolar or tetrapolar basidiomycetes that have either two linked mating-type-determining ( ) loci or two loci on separate chromosomes, in species studied thus far the two loci are arranged in a pseudobipolar configuration (linked on the same chromosome but capable of recombining).
View Article and Find Full Text PDFGenome copy number variation occurs during each mitotic and meiotic cycle and it is crucial for organisms to maintain their natural ploidy. Defects in ploidy transitions can lead to chromosome instability, which is a hallmark of cancer. Ploidy in the haploid human fungal pathogen Cryptococcus neoformans is exquisitely orchestrated and ranges from haploid to polyploid during sexual development and under various environmental and host conditions.
View Article and Find Full Text PDFSexual reproduction in fungi relies on proteins with well-known functions encoded by the mating type () loci. In the Basidiomycota, loci are often bipartite, with the locus encoding pheromone precursors and pheromone receptors and the locus encoding heterodimerizing homeodomain transcription factors (Hd1/Hd2). The interplay between different alleles of these genes within a single species usually generates at least two compatible mating types.
View Article and Find Full Text PDFHybridization has resulted in the origin and variation in extant species, and hybrids continue to arise despite pre- and post-zygotic barriers that limit their formation and evolutionary success. One important system that maintains species boundaries in prokaryotes and eukaryotes is the mismatch repair pathway, which blocks recombination between divergent DNA sequences. Previous studies illuminated the role of the mismatch repair component Msh2 in blocking genetic recombination between divergent DNA during meiosis.
View Article and Find Full Text PDFThe skin of humans and animals is colonized by commensal and pathogenic fungi and bacteria that share this ecological niche and have established microbial interactions. are the most abundant fungal skin inhabitant of warm-blooded animals and have been implicated in skin diseases and systemic disorders, including Crohn's disease and pancreatic cancer. Flavohemoglobin is a key enzyme involved in microbial nitrosative stress resistance and nitric oxide degradation.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
April 2020
A fundamental characteristic of eukaryotic organisms is the generation of genetic variation via sexual reproduction. Conversely, significant large-scale genome structure variations could hamper sexual reproduction, causing reproductive isolation and promoting speciation. The underlying processes behind large-scale genome rearrangements are not well understood and include chromosome translocations involving centromeres.
View Article and Find Full Text PDFCentromeres are chromosomal regions that serve as platforms for kinetochore assembly and spindle attachments, ensuring accurate chromosome segregation during cell division. Despite functional conservation, centromere DNA sequences are diverse and often repetitive, making them challenging to assemble and identify. Here, we describe centromeres in an oomycete Phytophthora sojae by combining long-read sequencing-based genome assembly and chromatin immunoprecipitation for the centromeric histone CENP-A followed by high-throughput sequencing (ChIP-seq).
View Article and Find Full Text PDFGenomic rearrangements associated with speciation often result in variation in chromosome number among closely related species. species show variable karyotypes ranging between six and nine chromosomes. Here, we experimentally identified all eight centromeres in as 3-5-kb long kinetochore-bound regions that span an AT-rich core and are depleted of the canonical histone H3.
View Article and Find Full Text PDFspecies utilize a variety of sexual reproduction mechanisms, which generate genetic diversity, purge deleterious mutations, and contribute to their ability to occupy myriad environmental niches and exhibit a range of pathogenic potential. The bisexual and unisexual cycles of pathogenic species are stimulated by properties associated with their environmental niches and proceed through well-characterized signaling pathways and corresponding morphological changes. Genes governing mating are encoded by the mating-type () loci and influence pathogenesis, population dynamics, and lineage divergence in .
View Article and Find Full Text PDFSexual development is a key evolutionary innovation of eukaryotes. In many species, mating involves interaction between compatible mating partners that can undergo cell and nuclear fusion and subsequent steps of development including meiosis. Mating compatibility in fungi is governed by the mating type (MAT) loci.
View Article and Find Full Text PDFSexual reproduction is vastly diverse and yet highly conserved across the eukaryotic domain. This ubiquity suggests that the last eukaryotic common ancestor (LECA) was sexual. It is hypothesized that several critical processes in sexual reproduction, including cell fusion and meiosis, were acquired during the evolution from the first eukaryotic common ancestor (FECA) to the sexual LECA.
View Article and Find Full Text PDFFungi reproduce via both heterothallic outcrossing and homothallic selfing modes, and transitions between the two are common throughout the tree of life. A new study reports that the transition from heterothallism to homothallism is common and has repeatedly punctuated the evolutionary trajectory across a major lineage of the fungal kingdom.
View Article and Find Full Text PDFSpeciation is a central mechanism of biological diversification. While speciation is well studied in plants and animals, in comparison, relatively little is known about speciation in fungi. One fungal model is the genus, which is best known for the pathogenic / species complex that causes >200,000 new human infections annually.
View Article and Find Full Text PDFThe region encompassing the Pacific Northwest (PNW), Vancouver Island, Oregon, and Washington has been the location of an ongoing outbreak since the 1990s, and there is evidence that the outbreak is expanding along the West Coast into California. Here we report a clinical case of a 69-year-old, HIV-negative man from North Carolina who was diagnosed with a fungal brain mass by magnetic resonance imaging (MRI) and pathology. He had traveled to Seattle and Vancouver 3 years earlier and to Costa Rica 4 months prior to presentation.
View Article and Find Full Text PDFConvergent adaptation provides unique insights into the predictability of evolution and ultimately into processes of biological diversification. Supergenes (beneficial gene linkage) are striking examples of adaptation, but little is known about their prevalence or evolution. A recent study on anther-smut fungi documented supergene formation by rearrangements linking two key mating-type loci, controlling pre- and post-mating compatibility.
View Article and Find Full Text PDFInt J Oral Maxillofac Implants
September 2018
Purpose: The objective of this investigation was to assess vertical bone augmentation using deproteinized bovine bone mineral (DBBM) infused or not with recombinant human bone morphogenetic protein (rhBMP-2) in rabbit tibiae.
Materials And Methods: A total of 18 female rabbits (New Zealand) received two blocks of DBBM in each tibia. The DBBM blocks were randomly assigned into four experimental groups: DBBM (only the bone graft); DBBM associated with absorbable collagen sponge (ACS); DBBM plus rhBMP-2 (1.
Sex chromosomes can display successive steps of recombination suppression known as "evolutionary strata," which are thought to result from the successive linkage of sexually antagonistic genes to sex-determining genes. However, there is little evidence to support this explanation. Here we investigate whether evolutionary strata can evolve without sexual antagonism using fungi that display suppressed recombination extending beyond loci determining mating compatibility despite lack of male/female roles associated with their mating types.
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