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  • Complete mitochondrial genome sequences of Korean native horse from Jeju Island: uncovering the spatio-temporal dynamics

    Molecular Biology Reports | 21 April 2017

    The Korean native horse (Jeju horse) is one of the most important animals in Korean historical, cultural, and economical viewpoints. In the early 1980s, the Jeju horse was close to extinction. The aim of this study is to explore the phylogenomics of Korean native horse focusing on spatio-temporal dynamics. We determined complete mitochondrial genome sequences for the first Korean native (n?=?6) and additional Mongolian (n?=?2) horses. Those sequences were analyzed together with 143 published ones using Bayesian coalescent approach as well as three different phylogenetic analysis methods, Bayesian inference, maximum likelihood, and neighbor-joining methods. The phylogenomic trees revealed that the Korean native horses had multiple origins and clustered together with some horses from four European and one Middle Eastern breeds. Our phylogenomic analyses also supported that there was no apparent association between breed or geographic location and the evolution of global horses. Time of the most recent common ancestor of the Korean native horse was approximately 13,200?63,200 years, which was much younger than 0.696 My of modern horses. Additionally, our results showed that all global horse lineages including Korean native horse existed prior to their domestication events occurred in about 6000?10,000 years ago. This is the first study on phylogenomics of the Korean native horse focusing on spatio-temporal dynamics. Our findings increase our understanding of the domestication history of the Korean native horses, and could provide useful information for horse conservation projects as well as for horse genomics, emergence, and the geographical distribution.

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  • Identification of a Novel Mutation in BRD4 that Causes Autosomal Dominant Syndromic Congenital Cataracts Associated with Other Neuro-Skeletal Anomalies.

    PLoS ONE | 11 Jan 2017

    Congenital cataracts can occur as a non-syndromic isolated ocular disease or as a part of genetic syndromes accompanied by a multi-systemic disease. Approximately 50% of all congenital cataract cases have a heterogeneous genetic basis. Here, we describe three generations of a family with an autosomal dominant inheritance pattern and common complex phenotypes, including bilateral congenital cataracts, short stature, macrocephaly, and minor skeletal anomalies. We did not find any chromosomal aberrations or gene copy number abnormalities using conventional genetic tests; accordingly, we conducted whole-exome sequencing (WES) to identify disease-causing genetic alterations in this family. Based on family WES data, we identified a novel BRD4 missense mutation as a candidate causal variant and performed cell-based experiments by ablation of endogenous BRD4 expression in human lens epithelial cells. The protein expression levels of connexin 43, p62, LC3BII, and p53 differed significantly between control cells and cells in which endogenous BRD4 expression was inhibited. We inferred that a BRD4 missense mutation was the likely disease-causing mutation in this family. Our findings may improve the molecular diagnosis of congenital cataracts and support the use of WES to clarify the genetic basis of complex diseases.

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  • Genome sequence of pacific abalone (Haliotis discus hannai): the first draft genome in family Haliotidae.

    Gigascience | 07 March 2017

    Background Abalones are large marine snails in the family Haliotidae and the genus Haliotis belonging to the class Gastropoda of the phylum Mollusca. The family Haliotidae contains only one genus, Haliotis, and this single genus is known to contain several species of abalone. With 18 additional subspecies, the most comprehensive treatment of Haliotidae considers 56 species valid [1]. Abalone is an economically important fishery and aquaculture animal which is considered a highly-prized seafood delicacy. The total global supply of abalone has increased fivefold since 1970’s and farm productions increased explosively from 50 mt to 103,464 mt in the past forty years. Additionally, researchers have recently focused on Abalone given their reported tumor suppression effect. However, despite the valuable features of this marine animal, no genomic information is available for Haliotidae family and related research is still limited.
    Findings In order to construct the H.discus hannai genome, a total of 580G base pairs using Illumina and Pacbio platforms were generated with 322-fold coverage based on the 1.8Gb estimated genome size of H.discus hannai using flow cytometry. The final genome assembly consisted of 1.86Gb with 35,450 scaffolds (>2kb). GC content level was 40.51%, and the N50 length of assembled scaffolds was 211kb. We identified 29,449 genes using Evidence Modeler based on the gene information from ab initio prediction, protein homology with known genes and transcriptome evidence of RNA-seq.
    Conclusions Here we present the first Haliotidae genome, Haliotis discus hannai, with sequencing data, assembly, and gene annotation information. This will be helpful for resolving the lack of genomic information in the Haliotidae family as well as providing more opportunities for understanding gastropod evolution.

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  • Genomic Insights and Its Comparative Analysis with Yersinia enterocolitica Reveals the Potential Virulence Determinants and Further Pathogenicity for Foodborne Outbreaks

    J. Microbiol. Biotechnol | 28 February 2017

    Yersinia enterocolitica is a well-known foodborne pathogen causing gastrointestinal infections worldwide. The strain Y. enterocolitica FORC_002 was isolated from the gill of flatfish (plaice) and its genome was sequenced. The genomic DNA consists of 4,837,317 bp with a GC content of 47.1%, and is predicted to contain 4,221 open reading frames, 81 tRNA genes, and 26 rRNA genes. Interestingly, genomic analysis revealed pathogenesis and host immune evasionassociated genes encoding guanylate cyclase (Yst), invasin (Ail and Inv), outer membrane protein (Yops), autotransporter adhesin A (YadA), RTX-like toxins, and a type III secretion system. In particular, guanylate cyclase is a heat-stable enterotoxin causing Yersinia-associated diarrhea, and RTX-like toxins are responsible for attachment to integrin on the target cell for cytotoxic action. This genome can be used to identify virulence factors that can be applied for the development of novel biomarkers for the rapid detection of this pathogen in foods.

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  • The genome landscape of indigenous African cattle

    Genome Biology | 20 February 2017

    Background
    The history of African indigenous cattle and their adaptation to environmental and human selection pressure is at the root of their remarkable diversity. Characterization of this diversity is an essential step towards understanding the genomic basis of productivity and adaptation to survival under African farming systems.

    Results
    We analyze patterns of African cattle genetic variation by sequencing 48 genomes from five indigenous populations and comparing them to the genomes of 53 commercial taurine breeds. We find the highest genetic diversity among African zebu and sanga cattle. Our search for genomic regions under selection reveals signatures of selection for environmental adaptive traits. In particular, we identify signatures of selection including genes and/or pathways controlling anemia and feeding behavior in the trypanotolerant N’Dama, coat color and horn development in Ankole, and heat tolerance and tick resistance across African cattle especially in zebu breeds.

    Conclusions
    Our findings unravel at the genome-wide level, the unique adaptive diversity of African cattle while emphasizing the opportunities for sustainable improvement of livestock productivity on the continent.

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  • Whole genome scan reveals the genetic signature of African Ankole cattle breed and potential for higher quality beef

    BMC Genetics | 9 February 2017

    Background
    Africa is home to numerous cattle breeds whose diversity has been shaped by subtle combinations of human and natural selection. African Sanga cattle are an intermediate type of cattle resulting from interbreeding between Bos taurus and Bos indicus subspecies. Recently, research has asserted the potential of Sanga breeds for commercial beef production with better meat quality as compared to Bos indicus breeds. Here, we identified meat quality related gene regions that are positively selected in Ankole (Sanga) cattle breeds as compared to indicus (Boran, Ogaden, and Kenana) breeds using cross-population (XP-EHH and XP-CLR) statistical methods.

    Results
    We identified 238 (XP-EHH) and 213 (XP-CLR) positively selected genes, of which 97 were detected from both statistics. Among the genes obtained, we primarily reported those involved in different biological process and pathways associated with meat quality traits. Genes (CAPZB, COL9A2, PDGFRA, MAP3K5, ZNF410, and PKM2) involved in muscle structure and metabolism affect meat tenderness. Genes (PLA2G2A, PARK2, ZNF410, MAP2K3, PLCD3, PLCD1, and ROCK1) related to intramuscular fat (IMF) are involved in adipose metabolism and adipogenesis. MB and SLC48A1 affect meat color. In addition, we identified genes (TIMP2, PKM2, PRKG1, MAP3K5, and ATP8A1) related to feeding efficiency. Among the enriched Gene Ontology Biological Process (GO BP) terms, actin cytoskeleton organization, actin filament-based process, and protein ubiquitination are associated with meat tenderness whereas cellular component organization, negative regulation of actin filament depolymerization and negative regulation of protein complex disassembly are involved in adipocyte regulation. The MAPK pathway is responsible for cell proliferation and plays an important role in hyperplastic growth, which has a positive effect on meat tenderness.

    Conclusion
    Results revealed several candidate genes positively selected in Ankole cattle in relation to meat quality characteristics. The genes identified are involved in muscle structure and metabolism, and adipose metabolism and adipogenesis. These genes help in the understanding of the biological mechanisms controlling beef quality characteristics in African Ankole cattle. These results provide a basis for further research on the genomic characteristics of Ankole and other Sanga cattle breeds for quality beef.

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  • Detecting Positive Selection of Korean Native Goat Populations Using Next-Generation Sequencing

    Molecules and Cells | 13 December 2016

    Goats (Capra hircus) are one of the oldest species of domesticated animals. Native Korean goats are a particularly interesting group, as they are indigenous to the area and were raised in the Korean peninsula almost 2,000 years ago. Although they have a small body size and produce low volumes of milk and meat, they are quite resistant to lumbar paralysis. Our study aimed to reveal the distinct genetic features and patterns of selection in native Korean goats by comparing the genomes of native Korean goat and crossbred goat populations. We sequenced the whole genome of 15 native Korean goats and 11 crossbred goats using next-generation sequencing (Illumina platform) to compare the genomes of the two populations. We found decreased nucleotide diversity in the native Korean goats compared to the crossbred goats. Genetic structural analysis demonstrated that the native Korean goat and crossbred goat populations shared a common ancestry, but were clearly distinct. Finally, to reveal the native Korean goat’s selective sweep region, selective sweep signals were identified in the native Korean goat genome using cross-population extended haplotype homozygosity (XP-EHH) and a cross-population composite likelihood ratio test (XP-CLR). As a result, we were able to identify candidate genes for recent selection, such as the CCR3 gene, which is related to lumbar paralysis resistance. Combined with future studies and recent goat genome information, this study will contribute to a thorough understanding of the native Korean goat genome.

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  • Complete genome of Vibrio parahaemolyticus FORC014 isolated from the toothfish

    Gut Pathogens | 17 November 2016

    Background
    Foodborne illness can occur due to various pathogenic bacteria such as Staphylococcus aureus, Escherichia coli and Vibrio parahaemolyticus, and can cause severe gastroenteritis symptoms. In this study, we completed the genome sequence of a foodborne pathogen V. parahaemolyticus FORC_014, which was isolated from suspected contaminated toothfish from South Korea. Additionally, we extended our knowledge of genomic characteristics of the FORC_014 strain through comparative analysis using the complete sequences of other V. parahaemolyticus strains whose complete genomes have previously been reported.

    Results
    The complete genome sequence of V. parahaemolyticus FORC_014 was generated using the PacBio RS platform with single molecule, real-time (SMRT) sequencing. The FORC_014 strain consists of two circular chromosomes (3,241,330 bp for chromosome 1 and 1,997,247 bp for chromosome 2), one plasmid (51,383 bp), and one putative phage sequence (96,896 bp). The genome contains a total of 4274 putative protein coding sequences, 126 tRNA genes and 34 rRNA genes. Furthermore, we found 33 type III secretion system 1 (T3SS1) related proteins and 15 type III secretion system 2 (T3SS2) related proteins on chromosome 1. This is the first reported result of Type III secretion system 2 located on chromosome 1 of V. parahaemolyticus without thermostable direct hemolysin (tdh) and thermostable direct hemolysin-related hemolysin (trh).

    Conclusions
    Through investigation of the complete genome sequence of V. parahaemolyticus FORC_014, which differs from previously reported strains, we revealed two type III secretion systems (T3SS1, T3SS2) located on chromosome 1 which do not include tdh and trh genes. We also identified several virulence factors carried by our strain, including iron uptake system, hemolysin and secretion system. This result suggests that the FORC_014 strain may be one pathogen responsible for foodborne illness outbreak. Our results provide significant genomic clues which will assist in future understanding of virulence at the genomic level and help distinguish between clinical and non-clinical isolates.

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  • Gut microbiota Modulated by Probiotics and Garcinia cambogia Extract Correlate with Weight Gain and Adipocyte Sizes in High Fat-Fed Mice

    Scientific Reports | 23 September 2016

    Results of recent studies on gut microbiota have suggested that obesogenic bacteria exacerbate obesity and metabolic dysfunction in the host when fed a high fat diet (HFD). In order to explore obesity-associated bacterial candidates and their response to diet, the composition of faecal bacterial communities was investigated by analyzing 16S rRNA gene sequences in mice. Dietary intervention with probiotics and Garcinia cambogia extract attenuated weight gain and adipocyte size in HFD-fed mice. To identify obesity-causative microbiota, two statistical analyses were performed. Forty-eight bacterial species were found to overlap between the two analyses, indicating the commonly identified species as diet-driven and obesity-associated, which would make them strong candidates for host-microbiome interaction on obesity. Finally, correlation based network analysis between diet, microbe, and host revealed that Clostridium aminophilum, a hyper-ammonia-producing bacterium, was highly correlated with obesity phenotypes and other associated bacteria, and shown to be suppressed by the combination of probiotics and Garcinia cambogia extract. Results of the present study suggest that probiotics and Garcinia cambogia extract alleviate weight gain and adiposity, in part via differentially modulating the composition of gut microbiota in HFD fed mice.

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  • Status of dosage compensation of X chromosome in bovine genome

    Genetica | 04 July 2016

    Dosage compensation system with X chromosome upregulation and inactivation have evolved to overcome the genetic imbalance between sex chromosomes in both male and female of mammals. Although recent development of chromosome-wide technologies has allowed us to test X upregulation, discrete data processing and analysis methods draw disparate conclusions. A series of expression studies revealed status of dosage compensation in some species belonging to monotremes, marsupials, rodents and primates. However, X upregulation in the Artiodactyla order including cattle have not been studied yet. In this study, we surveyed the genome-wide transcriptional upregulation in X chromosome in cattle RNA-seq data using different gene filtration methods. Overall examination of RNA-seq data revealed that X chromosome in the pituitary gland expressed more genes than in other peripheral tissues, which was consistent with the previous results observed in human and mouse. When analyzed with globally expressed genes, a median X:A expression ratio was 0.94. The ratio of 1-to-1 ortholog genes between chicken and mammals, however, showed considerable reduction to 0.68. These results indicate that status of dosage compensation for cattle is not deviated from those found in rodents and primate, and this is consistent with the evolutionary history of cattle.

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