The evolution of animals (metazoans) from their unicellular ancestors required the emergence of novel mechanisms for cell adhesion and cell-cell communication. One of the most important cell adhesion mechanisms for metazoan development is integrinmediated adhesion and signaling. The integrin adhesion complex mediates critical interactions between cells and the extracellular matrix, modulating several aspects of cell physiology. To date this machinery has been considered strictly metazoan specific. Here we report the results of a comparative genomic analysis of the integrin adhesion machinery, using genomic data from several unicellular relatives of Metazoa and Fungi. Unexpectedly, we found that core components of the integrin adhesion complex are encoded in the genome of the apusozoan protist Amastigomonas sp., and therefore their origins predate the divergence of Opisthokonta, the clade that includes metazoans and fungi. Furthermore, our analyses suggest that key components of this apparatus have been lost independently in fungi and choanoflagellates. Our data highlight the fact that many of the key genes that had formerly been cited as crucial for metazoan origins have a much earlier origin. This underscores the importance of gene cooption in the unicellular-to-multicellular transition that led to the emergence of the Metazoa.cell adhesion | lateral gene transfer | metazoan origins | multicellularity
BackgroundResolving the evolutionary relationships among Fungi remains challenging because of their highly variable evolutionary rates, and lack of a close phylogenetic outgroup. Nucleariida, an enigmatic group of amoeboids, have been proposed to emerge close to the fungal-metazoan divergence and might fulfill this role. Yet, published phylogenies with up to five genes are without compelling statistical support, and genome-level data should be used to resolve this question with confidence.ResultsOur analyses with nuclear (118 proteins) and mitochondrial (13 proteins) data now robustly associate Nucleariida and Fungi as neighbors, an assemblage that we term 'Holomycota'. With Nucleariida as an outgroup, we revisit unresolved deep fungal relationships.ConclusionOur phylogenomic analysis provides significant support for the paraphyly of the traditional taxon Zygomycota, and contradicts a recent proposal to include Mortierella in a phylum Mucoromycotina. We further question the introduction of separate phyla for Glomeromycota and Blastocladiomycota, whose phylogenetic positions relative to other phyla remain unresolved even with genome-level datasets. Our results motivate broad sampling of additional genome sequences from these phyla.
Human papillomavirus (HPV) type 52 DNA was detected in cervicovaginal lavage samples from 91 (12.4%) of 732 human immunodeficiency virus (HIV)-seropositive women and 23 (7.1%) of 323 HIV-seronegative women (P=.0004). HIV infection was an independent predictor for HPV-52 infection when controlling for age and sexual activity (odds ratio, 2.21; 95% confidence interval, 1.30-3.75: P=.003). We describe the genomic polymorphism of 114 HPV-52 isolates. Long control region (LCR) mutations defined 27 HPV-52 variants. Nearly 32% of HPV-52 isolates carried deletions in the LCR. E6 and E7 mutations defined 17 and 9 variants, respectively. Five nonsynonymous E6 mutations were clustered from amino acids 92 to 94, near the putative p53 binding area. White women were more frequently infected by the prototype strain than were women of African descent (P=.0001). The genetic diversity of HPV-52 should facilitate the investigation of the role of genomic variations in cervical disease.
Background: Sequence data analyses such as gene identification, structure modeling or phylogenetic tree inference involve a variety of bioinformatics software tools. Due to the heterogeneity of bioinformatics tools in usage and data requirements, scientists spend much effort on technical issues including data format, storage and management of input and output, and memorization of numerous parameters and multi-step analysis procedures.
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