scholarly journals Phylogenetic Analysis of Core Melanin Synthesis Genes Provides Novel Insights Into the Molecular Basis of Albinism in Fish

2021 ◽  
Vol 12 ◽  
Author(s):  
Chao Bian ◽  
Ruihan Li ◽  
Zhengyong Wen ◽  
Wei Ge ◽  
Qiong Shi
Keyword(s):  
Genomic Analysis ◽  
Comparative Genomic ◽  
Melanin Synthesis ◽  
Loss Of Function ◽  
Nonsense Mutations ◽  
Astyanax Mexicanus ◽  
Genomic Studies ◽  
Skin Coloration ◽  
Molecular Guidance ◽  
Core Genes

Melanin is the most prevalent pigment in animals. Its synthesis involves a series of functional genes. Particularly, teleosts have more copies of these genes related to the melanin synthesis than tetrapods. Despite the increasing number of available vertebrate genomes, a few systematically genomic studies were reported to identify and compare these core genes for the melanin synthesis. Here, we performed a comparative genomic analysis on several core genes, including tyrosinase genes (tyr, tyrp1, and tyrp2), premelanosome protein (pmel), microphthalmia-associated transcription factor (mitf), and solute carrier family 24 member 5 (slc24a5), based on 90 representative vertebrate genomes. Gene number and mutation identification suggest that loss-of-function mutations in these core genes may interact to generate an albinism phenotype. We found nonsense mutations in tyrp1a and pmelb of an albino golden-line barbel fish, in pmelb of an albino deep-sea snailfish (Pseudoliparis swirei), in slc24a5 of cave-restricted Mexican tetra (Astyanax mexicanus, cavefish population), and in mitf of a transparent icefish (Protosalanx hyalocranius). Convergent evolution may explain this phenomenon since nonsense mutations in these core genes for melanin synthesis have been identified across diverse albino fishes. These newly identified nonsense mutations and gene loss will provide molecular guidance for ornamental fish breeding, further enhancing our in-depth understanding of human skin coloration.

scholarly journals Comparative Genomic Analysis of Bifidobacterium Catenulatum Reveal the Genetic Divergence of its Two Subspecies from Infant and Adult Gut

2021 ◽  
Author(s):  
Jiaqi Liu ◽  
Weicheng Li ◽  
Caiqing Yao ◽  
Jie Yu ◽  
Heping Zhang
Keyword(s):  
Genetic Divergence ◽  
Gc Content ◽  
Genomic Analysis ◽  
Glycoside Hydrolases ◽  
Comparative Genomic ◽  
Carbohydrate Binding ◽  
Functional Difference ◽  
Carbohydrate Utilization ◽  
Carbohydrate Binding Modules ◽  
Genomic Studies

Abstract Background: Bifidobacterium catenulatum, which includes two subspecies that B. catenulatum subsp. kashiwanohense and B. catenulatum subsp. catenulatum are usually from infant and adult gut respectively, while the genomic studies of functional difference and genetic divergence in them have been rarely reported. In this study, we analyzed 16 B. catenulatum strains through comparative genomics, including two novel sequenced strains. Results: A phylogenetic tree based on 785 core genes indicated that the two subspecies of B. catenulatum were significantly separated and confirmed their colonizing bias in infants and adults. Comparison of general genomic characteristics revealed that the two subspecies had significantly different genomic sizes but similar GC content. Functional annotations found that they peculiarly differ in utilization of carbohydrates and amino acid. Among them, we found that carbohydrate metabolism seems to play an important role in the divergence because of their carbohydrate-active enzymes (CAZyme) present two different clustering patterns. B. catenulatum subsp. kashiwanohense have functional genes that specifically adapted to the infant gut for glycoside hydrolases 95 (GH95) and carbohydrate-binding modules 51 (CBM51), which specifically participated in the metabolism of Human Milk Oligosaccharides (HMOs), and specific genes fuc that related to HMOs were also detected. While B. catenulatum subsp. catenulatum rich in GH3 and glycosyltransferases 4 (GT4) tended to metabolize plant-derived glycan that may help it metabolize more complex carbohydrates (eg. xylan) in the adult intestine. Conclusions: Our findings revealed genomic evidence of carbohydrate utilization bias which may be a key leading to the genetic divergence of two subspecies of B. catenulatum.

scholarly journals Characterization of a blaNDM-1-Bearing IncHI5-Like Plasmid From Klebsiella pneumoniae of Infant Origin

2021 ◽  
Vol 11 ◽  
Author(s):  
Ziyi Liu ◽  
Ruifei Chen ◽  
Poshi Xu ◽  
Zhiqiang Wang ◽  
Ruichao Li
Keyword(s):  
Klebsiella Pneumoniae ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Genetic Composition ◽  
Carbapenem Resistant ◽  
Antimicrobial Resistance Genes ◽  
Genes Encoding ◽  
History Of ◽  
Core Genes

The spread of plasmid-mediated carbapenem-resistant clinical isolates is a serious threat to global health. In this study, an emerging NDM-encoding IncHI5-like plasmid from Klebsiella pneumoniae of infant patient origin was characterized, and the plasmid was compared to the available IncHI5-like plasmids to better understand the genetic composition and evolution of this emerging plasmid. Clinical isolate C39 was identified as K. pneumoniae and belonged to the ST37 and KL15 serotype. Whole genome sequencing (WGS) and analysis revealed that it harbored two plasmids, one of which was a large IncHI5-like plasmid pC39-334kb encoding a wide variety of antimicrobial resistance genes clustered in a single multidrug resistance (MDR) region. The blaNDM-1 gene was located on a ΔISAba125-blaNDM-1-bleMBL-trpF-dsbC structure. Comparative genomic analysis showed that it shared a similar backbone with four IncHI5-like plasmids and the IncHI5 plasmid pNDM-1-EC12, and these six plasmids differed from typical IncHI5 plasmids. The replication genes of IncHI5-like plasmids shared 97.06% (repHI5B) and 97.99% (repFIB-like) nucleotide identity with those of IncHI5 plasmids. Given that pNDM-1-EC12 and all IncHI5-like plasmids are closely related genetically, the occurrence of IncHI5-like plasmid is likely associated with the mutation of the replication genes of pNDM-1-EC12-like IncHI5 plasmids. All available IncHI5-like plasmids harbored 262 core genes encoding replication and maintenance functions and carried distinct MDR regions. Furthermore, 80% of them (4/5) were found in K. pneumoniae from Chinese nosocomial settings. To conclude, this study expands our knowledge of the evolution history of IncHI5-like plasmids, and more attention should be paid to track the evolution pathway of them among clinical, animal, and environmental settings.

scholarly journals Diversity, evolution, and classification of virophages uncovered through global metagenomics

Microbiome ◽  
2019 ◽  
Vol 7 (1) ◽  
Author(s):  
David Paez-Espino ◽  
Jinglie Zhou ◽  
Simon Roux ◽  
Stephen Nayfach ◽  
Georgios A. Pavlopoulos ◽  
...  
Keyword(s):  
Genomic Analysis ◽  
Comparative Genomic ◽  
Human Gut ◽  
High Quality ◽  
Double Stranded Dna ◽  
Terrestrial Subsurface ◽  
Public Collection ◽  
Reference Genomes ◽  
Core Genes

Abstract Background Virophages are small viruses with double-stranded DNA genomes that replicate along with giant viruses and co-infect eukaryotic cells. Due to the paucity of virophage reference genomes, a collective understanding of the global virophage diversity, distribution, and evolution is lacking. Results Here we screened a public collection of over 14,000 metagenomes using the virophage-specific major capsid protein (MCP) as “bait.” We identified 44,221 assembled virophage sequences, of which 328 represent high-quality (complete or near-complete) genomes from diverse habitats including the human gut, plant rhizosphere, and terrestrial subsurface. Comparative genomic analysis confirmed the presence of four core genes in a conserved block. We used these genes to establish a revised virophage classification including 27 clades with consistent genome length, gene content, and habitat distribution. Moreover, for eight high-quality virophage genomes, we computationally predicted putative eukaryotic virus hosts. Conclusion Overall, our approach has increased the number of known virophage genomes by 10-fold and revealed patterns of genome evolution and global virophage distribution. We anticipate that the expanded diversity presented here will provide the backbone for further virophage studies.

scholarly journals Comparative cytogenomics reveals genome reshuffling and centromere repositioning in the legume tribe Phaseoleae

2021 ◽  
Author(s):  
Claudio Montenegro ◽  
Livia Martins ◽  
Fernanda de Oliveira Bustamante ◽  
Ana Christina Brasileiro-Vidal ◽  
Andrea Pedrosa-Harand
Keyword(s):  
Genomic Analysis ◽  
In Silico Analysis ◽  
Comparative Genomic Analysis ◽  
Comparative Genomic ◽  
Orthologous Genes ◽  
Genomic Analyses ◽  
Genomic Studies ◽  
Macroptilium Atropurpureum ◽  
Evolutionary New Centromeres ◽  
Silico Analysis

The tribe Phaseoleae (Leguminosae; Papilionoideae) includes several legume crops with assembled genomes. Comparative genomic studies indicated the preservation of large genomic blocks in legumes. However, the chromosome dynamics along its evolution was not investigated in the tribe. We conducted a comparative genomic analysis using CoGe Synmap platform to define a useful genomic block (GB) system and to reconstruct the ancestral Phaseoleae karyotype (APK). We defined the GBs based on orthologous genes between Phaseolus vulgaris and Vigna unguiculata genomes (n = 11), then searched for these GBs in different genome species belonging to the Phaseolinae (P. lunatus, n = 11) and Glycininae (Amphicarpaea edgeworthii, n = 11 and Spatholobus suberectus, n = 9) subtribes, and in the outgroup (Medicago truncaluta, n = 8). To support our in silico analysis, we used oligo-FISH probes of P. vulgaris chromosomes 2 and 3 to paint the orthologous chromosomes of the non-sequenced Phaseolinae species (Macroptilium atropurpureum and Lablab purpureusi, n = 11). We inferred the APK with n = 11, 22 GBs (A to V) and 60 sub-GBs. We hypothesized that the main rearrangements within Phaseolinae involved nine APK chromosomes, with extensive centromere repositioning resulting from evolutionary new centromeres (ENC) in the Phaseolus lineage. We demonstrated that the A. edgeworthii genome is more reshuffled than the dysploid S. suberectus genome, in which we could reconstructed the main events responsible for the chromosome number reduction. The development of the GB system and the proposed APK provide useful tools for future comparative genomic analyses of legume species.

scholarly journals Comparative Genomic Analysis of Rhodococcus equi: An Insight into Genomic Diversity and Genome Evolution

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Jianchao Ying ◽  
Jun Ye ◽  
Teng Xu ◽  
Qian Wang ◽  
Qiyu Bao ◽  
...  
Keyword(s):  
Core Genome ◽  
Genomic Analysis ◽  
Rhodococcus Equi ◽  
Comparative Genomic Analysis ◽  
Genomic Islands ◽  
Genomic Diversity ◽  
Comparative Genomic ◽  
Niche Adaptation ◽  
Genomic Studies ◽  
Insight Into

Rhodococcus equi, a member of the Rhodococcus genus, is a gram-positive pathogenic bacterium. Rhodococcus possesses an open pan-genome that constitutes the basis of its high genomic diversity and allows for adaptation to specific niche conditions and the changing host environments. Our analysis further showed that the core genome of R. equi contributes to the pathogenicity and niche adaptation of R. equi. Comparative genomic analysis revealed that the genomes of R. equi shared identical collinearity relationship, and heterogeneity was mainly acquired by means of genomic islands and prophages. Moreover, genomic islands in R. equi were always involved in virulence, resistance, or niche adaptation and possibly working with prophages to cause the majority of genome expansion. These findings provide an insight into the genomic diversity, evolution, and structural variation of R. equi and a valuable resource for functional genomic studies.

scholarly journals The hidden pangenome: comparative genomics reveals pervasive diversity in symbiotic and free-living sulfur-oxidizing bacteria

2020 ◽  
Author(s):  
Rebecca Ansorge ◽  
Stefano Romano ◽  
Lizbeth Sayavedra ◽  
Maxim Rubin-Blum ◽  
Harald Gruber-Vodicka ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Hydrothermal Vents ◽  
Driving Forces ◽  
Genetic Material ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Free Living ◽  
Bacterial Populations ◽  
Genomic Studies ◽  
Sulfur Oxidizing

AbstractSulfur-oxidizing Thioglobaceae, often referred to as SUP05 and Arctic96BD clades, are widespread and common to hydrothermal vents and oxygen minimum zones. They impact global biogeochemical cycles and exhibit a variety of host-associated and free-living lifestyles. The evolutionary driving forces that led to the versatility, adoption of multiple lifestyles and global success of this family are largely unknown. Here, we perform an in-depth comparative genomic analysis using all available and newly generated Thioglobaceae genomes. Gene content variation was common, throughout taxonomic ranks and lifestyles. We uncovered a pool of variable genes within most Thioglobaceae populations in single environmental samples and we referred to this as the ‘hidden pangenome’. The ‘hidden pangenome’ is often overlooked in comparative genomic studies and our results indicate a much higher intra-specific diversity within environmental bacterial populations than previously thought. Our results show that core-community functions are different from species core genomes suggesting that core functions across populations are divided among the intra-specific members within a population. Defense mechanisms against foreign DNA and phages were enriched in symbiotic lineages, indicating an increased exchange of genetic material in symbioses. Our study suggests that genomic plasticity and frequent exchange of genetic material drives the global success of this family by increasing its evolvability in a heterogeneous environment.

scholarly journals Small Cell Carcinoma of the Ovary, Hypercalcemic Type (SCCOHT) beyond SMARCA4 Mutations: A Comprehensive Genomic Analysis

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1496 ◽  
Author(s):  
Aurélie Auguste ◽  
Félix Blanc-Durand ◽  
Marc Deloger ◽  
Audrey Le Formal ◽  
Rohan Bareja ◽  
...  
Keyword(s):  
Cell Carcinoma ◽  
Small Cell Carcinoma ◽  
Functional Data ◽  
Ovarian Tissue ◽  
Genomic Analysis ◽  
Genomic Stability ◽  
Small Cell ◽  
Comparative Genomic ◽  
Loss Of Function ◽  
Carcinoma Of The Ovary

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is an aggressive malignancy that occurs in young women, is characterized by recurrent loss-of-function mutations in the SMARCA4 gene, and for which effective treatments options are lacking. The aim of this study was to broaden the knowledge on this rare malignancy by reporting a comprehensive molecular analysis of an independent cohort of SCCOHT cases. We conducted Whole Exome Sequencing in six SCCOHT, and RNA-sequencing and array comparative genomic hybridization in eight SCCOHT. Additional immunohistochemical, Sanger sequencing and functional data are also provided. SCCOHTs showed remarkable genomic stability, with diploid profiles and low mutation load (mean, 5.43 mutations/Mb), including in the three chemotherapy-exposed tumors. All but one SCCOHT cases exhibited 19p13.2-3 copy-neutral LOH. SMARCA4 deleterious mutations were recurrent and accompanied by loss of expression of the SMARCA2 paralog. Variants in a few other genes located in 19p13.2-3 (e.g., PLK5) were detected. Putative therapeutic targets, including MAGEA4, AURKB and CLDN6, were found to be overexpressed in SCCOHT by RNA-seq as compared to benign ovarian tissue. Lastly, we provide additional evidence for sensitivity of SCCOHT to HDAC, DNMT and EZH2 inhibitors. Despite their aggressive clinical course, SCCOHT show remarkable inter-tumor homogeneity and display genomic stability, low mutation burden and few somatic copy number alterations. These findings and preliminary functional data support further exploration of epigenetic therapies in this lethal disease.

scholarly journals Evolutionary Divergence of the Novel Staphylococcal Species Staphylococcus argenteus

2021 ◽  
Vol 12 ◽  
Author(s):  
Shi Wu ◽  
Rui Pang ◽  
Jiahui Huang ◽  
Feng Zhang ◽  
Zhihe Cai ◽  
...  
Keyword(s):  
Genomic Analysis ◽  
Comparative Genomic ◽  
Evolutionary Divergence ◽  
The Novel ◽  
Staphylococcal Species ◽  
Comprehensive Information ◽  
Antimicrobial Resistance Genes ◽  
Invasive Infections ◽  
Genomic Studies ◽  
Epidemiological Characteristics

Currently, invasive infections caused by Staphylococcus argenteus, which is a recently named staphylococcal species, are increasingly reported worldwide. However, only a few genomic studies of S. argenteus have offered comprehensive information regarding its genetic diversity, epidemiological characteristics, antimicrobial resistance genes (ARGs), virulence genes and other profiles. Here, we describe a comparative genomic analysis by population structure, pangenome, panmobilome, region-specific accessory genes confer an adaptive advantage in 153 S. argenteus strains which comprised 24 strains sequenced in this study and 129 strains whose genome sequences were available from GenBank. As a result, the population of S. argenteus comprised seven genetically distinct clades, including two major clades (C1 and C2), with distinct isolation source patterns. Pangenome analysis revealed that S. argenteus has an open pangenome composed of 7,319 genes and a core genome composed of 1,508 genes. We further determined the distributions of 75 virulence factors (VFs) and 30 known ARGs and identified at least four types of plasmids and 93 complete or partial putative prophages. It indicate that S. argenteus may show a similar level of pathogenicity to that of S. aureus. This study also provides insights into the evolutionary divergence of this pathogen, indicating that the geographical distribution was a potential driving force behind the evolutionary divergence of S. argenteus. The preferential horizontal acquisition of particular elements, such as staphylococcal cassette chromosome mec elements and plasmids, was observed in specific regions, revealing potential gene exchange between S. argenteus strains and local S. aureus strains. Moreover, multiple specific genes related to environmental adaptation were identified in strains isolated from East Asia. However, these findings may help promote our understanding of the evolutionary divergence of this bacterium at a high genetic resolution by providing insights into the epidemiology of S. argenteus and may help combat its spread.

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