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PubMed1997

RNA profile and structural protein analysis of rotaviruses isolated from diarrhoeal calves in India.

Two isolates of group A rotaviruses (CR129 and CR156) were isolated from faecal samples of diarrhoeal calves reared in two dairy farms at Hisar (Haryana, India) by using MA-104 cell lines. These isolates were compared with three standard reference bovine rotaviruses, UK, NCDV and B223, to reveal differences, if any, in their genome and protein migration profiles. The migration of RNA segment 4 of CR129 was slower than that of NCDV, but faster than that of UK. Segment 10 of CR156 moved faster than that of the reference viruses. The segments 2 and 3 co-migrated in CR129, but resolved separately in CR156. Five protein bands of size 116-120 KD (VP1), 95 KD (VP2), 90 KD (VP3/VP4), 44 KD (VP6) and 34 KD (VP7) were detected by protein analysis. No significant difference was observed in the protein profile of these two bovine rotavirus isolates by immunoblotting. However, VP1 was of approximately 116 KD size in the two isolates, compared to 120 KD in the reference strains. These findings indicate that these rotaviruses isolated from diarrhoeic Indian calves differed from the 3 reference strains.

Animals↗
PubMed1997

Towards the quantitative traits regulation: fountain theory implications in comparative and developmental biology.

A fountain mechanism of quantitative regulation of gene expression level during development is proposed. The mechanism is based on postulated ability of a special class of RNA molecules, so called fountain RNAs (fRNAs), to induce passive and selective ionic channels in the internal nuclear membrane. Ions diffuse via channel from the nuclear lumen into the chromatin compartment. An RNA-dependent battery of ion channels is assumed to produce < > of ions in close vicinity to the corresponding genes. An ion atmosphere, in its turn, locally changes the chromatin configuration and effectiveness of transcription and processing of transcripts. Hence this mechanism can be used to change genes productivity. It is a basic mechanism of quantitative traits regulation. A passive selective ion flux periodically stops after a threshold ion concentration induces local chromatin compactization and arrests the activity of ion channels in a given chromatin compartment. This process serves as a basis for many cellular biorhythms that are relatively temperature-independent because of the passive nature of ion channel. It is postulated that eukaryotes became eukaryotes just to obtain this fountain mechanism that allows them to perform gradual quantitative modulation of corresponding genes expression levels. The fountain mechanism is partly responsible for dominance and heterosis, X-chromosome inactivation, gene position effects, and some other epigenetic events. It plays an important role in embryonic and post-embryonic development. A significant portion of the former < > DNA can be referred to as fDNA involved in the proposed mechanism functioning. Genomic rearrangements of fDNA could lead to micro- and macroevolutionary changes in the animal and plant kingdoms. The pivotal evolutionary function of transposons could reside in their ability to contain and relocate fDNA along the chromosomes.

Animals↗
PubMed1994

Characterization of 65 bovine microsatellites.

Microsatellites or simple sequence repeat (SSR) polymorphisms are used widely in the construction of linkage maps in many species. High levels of polymorphism coupled with the ease of analysis of the polymerase chain reaction (PCR) have resulted in this type of maker being one of the most widely used for genetic analysis. In this paper we describe 58 polymorphic bovine microsatellites that were isolated from insert size selected bovine genomic libraries. Primer sequences, number of alleles, and heterozygosity levels in cattle reference families are reported. Chromosomal locations for 47 of these microsatellites as well as for 7 previously described systems derived from entries in the Genbank or EMBL databases have been determined. The markers map to 24 syntenic or chromosomal locations. Polymorphic bovine microsatellites were estimated to occur, on average, every 320 kb, and there is no evidence of clustering in the genome. Thirty of the bovine-derived microsatellite systems gave specific and polymorphic products in sheep, adding to the number of useful markers in that species.

Animals↗
PubMed1987

Molecular analysis of elements inserted into mouse gamma-actin processed pseudogenes.

DNA from ten mouse genomic clones, each containing distinct gamma-actin processed pseudogenes, was subjected to electron microscopic heteroduplex analysis, and in three cases (lambda mA36, lambda mA118 and lambda mA119) the heteroduplex formed with the DNA of a reference clone was found to be interrupted by a single-stranded loop. The genomic regions corresponding to these loops were subjected to structural analysis and they were found to represent different elements (IEs) inserted into the pseudogenes in a manner that gave rise to short target-site direct repeats. IE 36 (500 base-pairs in length) was found to be an intercisternal A-particle solo long terminal repeat (LTR), a 46 nucleotide region of which had undergone five-fold tandem amplification and subsequent mutation. IE 119 (501 base-pairs in length) was also a solo LTR, bearing similarity to the recently-described GLN-3 class of murine retroviral-like elements. IE 118 (865 base-pairs in length) is repeated 1000-2000 times in the mouse genome. It is not related to any known class of mobile elements, but does possess some sequence motifs that suggest it may be an LTR of a hitherto unrecognized family of retroviral-like elements. It also possesses a 26 out of 27 nucleotide identity to a region of the flanking pseudogene, suggesting that it may have suffered gene conversion.

Actins↗
PubMed2005

Conservation anchors in the vertebrate genome.

Genomic segments that do not code for proteins yet show high conservation among vertebrates have recently been identified by various computational methodologies. We refer to them as ANCORs (ancestral non-coding conserved regions). The frequency of individual ANCORs within the genome, along with their (correlated) inter-species identity scores, helps in assessing the probability that they function in transcription regulation or RNA coding.

Animals↗
PubMed1995

Genomic diversity and phylogenetic relationships among lipid-requiring diphtheroids from humans and characterization of Corynebacterium macginleyi sp. nov.

DNA relatedness experiments were performed with 38 clinical isolates and 13 reference strains of coryneform taxa exhibiting a lipid requirement for optimal growth. Forty-five of these strains split into five genomic groups at the species level, whereas six other strains remained unclustered. Genomospecies II fits Corynebacterium accolens, but the other genomospecies were not genetically related to any of the defined Corynebacterium species. Phylogenetic analyses of genes coding for small-subunit rRNA sequences revealed that two genomospecies (I and III) and C. accolens form a tight cluster within the robust branch that groups all Corynebacterium species presently sequenced. Reference strains of biotypes C-1, C-2, and C-3 of "Corynebacterium pseudogenitalium" were found to fall into genomospecies I, as well as "Corynebacterium tuberculostearicum," Centers for Disease Control and Prevention (CDC) coryneform group G-1, and CDC coryneform group G-2 reference strains. Biochemical tests allowed differentiation between genomospecies except between genomospecies IV and V and between six unclustered strains and genomospecies I. We propose a new classification for these lipid-requiring diphtheroids within the genus Corynebacterium with the delineation of some CDC coryneform group G-1 strains (genomospecies III) as a new species for which the name Corynebacterium macginleyi is proposed. The type strain is strain JCL-2 (CIP 104099), isolated from a human corneal ulcer.

Base Sequence↗
PubMed2005

Molecular phylogenetics of 'river dolphins' and the baiji mitochondrial genome.

It is well known that the classical river dolphins are not a natural group, but up to now the phylogenetic relationships among them are not very clear because different views have been referred from different studies. In the present study, we determined the complete nucleotide sequence of the mitochondrial (mt) genome of the baiji (Lipotes vexillifer), the most endangered cetacean species, and conducted phylogenetic analyses for the classical river dolphins based on data from cetacean mitochondrial genomes available. In our analyses, the classical river dolphins split into two separate lineages, Platanista and Lipotes+(Inia+Pontoporia), having no sister relationship with each other, and the Platanista lineage is always within the odontocete clade instead of having a closer affinity to Mysticeti. The position of the Platanista is more basal, suggesting separate divergence of this lineage well before the other one. The Lipotes has a sister relationship with Inia+pontoporia, and they together formed the sister group to the Delphinoidea. This result strongly supports paraphyly of the classical river dolphins, and the nonplatanistoid river dolphins do represent a monophyletic grouping, with the Lipotidae as the sister taxa to (Iniidae+Pontoporiidae), and is well congruent with the studies based on short interspersed repetitive elements (SINEs).

Animals↗
PubMed2006

Evolutionary rates, divergence dates, and the performance of mitochondrial genes in Bayesian phylogenetic analysis.

The mitochondrial genome is one of the most frequently used loci in phylogenetic and phylogeographic analyses, and it is becoming increasingly possible to sequence and analyze this genome in its entirety from diverse taxa. However, sequencing the entire genome is not always desirable or feasible. Which genes should be selected to best infer the evolutionary history of the mitochondria within a group of organisms, and what properties of a gene determine its phylogenetic performance? The current study addresses these questions in a Bayesian phylogenetic framework with reference to a phylogeny of plethodontid and related salamanders derived from 27 complete mitochondrial genomes; this topology is corroborated by nuclear DNA and morphological data. Evolutionary rates for each mitochondrial gene and divergence dates for all nodes in the plethodontid mitochondrial genome phylogeny were estimated in both Bayesian and maximum likelihood frameworks using multiple fossil calibrations, multiple data partitions, and a clock-independent approach. Bayesian analyses of individual genes were performed, and the resulting trees compared against the reference topology. Ordinal logistic regression analysis of molecular evolution rate, gene length, and the G-shape parameter a demonstrated that slower rate of evolution and longer gene length both increased the probability that a gene would perform well phylogenetically. Estimated rates of molecular evolution vary 84-fold among different mitochondrial genes and different salamander lineages, and mean rates among genes vary 15-fold. Despite having conserved amino acid sequences, cox1, cox2, cox3, and cob have the fastest mean rates of nucleotide substitution, and the greatest variation in rates, whereas rrnS and rrnL have the slowest rates. Reasons underlying this rate variation are discussed, as is the extensive rate variation in cox1 in light of its proposed role in DNA barcoding.

Animals↗
PubMed2004

QTL analysis and comparative genomics of herbage quality traits in perennial ryegrass (Lolium perenne L.).

Genetic control of herbage quality variation was assessed through the use of the molecular marker-based reference genetic map of perennial ryegrass (Lolium perenne L.). The restriction fragment length polymorphism (RFLP), amplified fragment length polymorphism (AFLP) and genomic DNA-derived simple sequence repeat-based (SSR) framework marker set was enhanced, with RFLP loci corresponding to genes for key enzymes involved in lignin biosynthesis and fructan metabolism. Quality traits such as crude protein (CP) content, estimated in vivo dry matter digestibility (IVVDMD), neutral detergent fibre content (NDF), estimated metabolisable energy (EstME) and water soluble carbohydrate (WSC) content were measured by near infrared reflectance spectroscopy (NIRS) analysis of herbage harvests. Quantitative trait locus (QTL) analysis was performed using single-marker regression, simple interval mapping and composite interval mapping approaches, detecting a total of 42 QTLs from six different sampling experiments varying by developmental stage (anthesis or vegetative growth), location or year. Coincident QTLs were detected on linkage groups (LGs) 3, 5 and 7. The region on LG3 was associated with variation for all measured traits across various experimental datasets. The region on LG7 was associated with variation for all traits except CP, and is located in the vicinity of the lignin biosynthesis gene loci xlpomt1 (caffeic acid-O-methyltransferase), xlpccr1 (cinnamoyl CoA-reductase) and xlpssrcad 2.1 (cinnamyl alcohol dehydrogenase). Comparative genomics analysis of these gene classes with wheat (Triticum aestivum L.) provides evidence for conservation of gene order over evolutionary time and the basis for cross-specific genetic information transfer. The identification of co-location between QTLs and functionally associated genetic markers is critical for the implementation of marker-assisted selection programs and for linkage disequilibrium studies, which will enable future improvement strategies for perennial ryegrass.

Chromosome Mapping↗
PubMed2002

Measuring conservation of contiguous sets of autosomal markers on bovine and porcine genomes in relation to the map of the human genome.

Based on published information, we have identified 991 genes and gene-family clusters for cattle and 764 for pigs that have orthologues in the human genome. The relative linear locations of these genes on human sequence maps were used as "rulers" to annotate bovine and porcine genomes based on a CSAM (contiguous sets of autosomal markers) approach. A CSAM is an uninterrupted set of markers in one genome (primary genome; the human genome in this study) that is syntenic in the other genome (secondary genome; the bovine and porcine genomes in this study). The analysis revealed 81 conserved syntenies and 161 CSAMs between human and bovine autosomes and 50 conserved syntenies and 95 CSAMs between human and porcine autosomes. Using the human sequence map as a reference, these 991 and 764 markers could correlate 72 and 74% of the human genome with the bovine and porcine genomes, respectively. Based on the number of contiguous markers in each CSAM, we classified these CSAMs into five size groups as follows: singletons (one marker only), small (2-4 markers), medium (5-10 markers), large (11-20 markers), and very large (> 20 markers). Several bovine and porcine chromosomes appear to be represented as di-CSAM repeats in a tandem or dispersed way on human chromosomes. The number of potential CSAMs for which no markers are currently available were estimated to be 63 between human and bovine genomes and 18 between human and porcine genomes. These results provide basic guidelines for further gene and QTL mapping of the bovine and porcine genomes, as well as insight into the evolution of mammalian genomes.

Animals↗
PubMed2003

Discrepancy between macroscopic and microscopic transitional zones in Hirschsprung's disease with reference to the type of RET/GDNF/SOX10 gene mutation.

BACKGROUND/PURPOSE: Recent studies have found that Hirschsrung's disease is caused by diverse genomic abnormalities. To clarify whether these pathogenic variations influence the distribution and function of enteric ganglia, the authors studied the morphology of the macroscopic and microscopic transitional zone in Hirschsprung's disease with reference to the type of genetic mutation. METHODS: In 120 patients with Hirschsprung's disease, the location and morphology of the gut caliber change were recorded, and the enteric nervous system was investigated histologically using biopsy specimens. The DNA sequences of all the RET/GDNF/NTN and SOX10 coding regions were determined using the direct DyeDeoxy Terminator Cycle method. RESULTS: In RET mutation carriers, the gut caliber change was almost identical to the histologic transition in cases of short segment aganglionosis, whereas these were markedly dissociated in cases exhibiting extensive aganglionosis. In contrast, SOX10 mutation carriers had a very long histologic transition and exhibited no caliber change. CONCLUSIONS: The type of genetic mutation responsible for Hirschsprung's disease influences the postnatal distribution and function of enteric ganglia. The data on discrepancy between macroscopic and microscopic transitions may enable us to concentrate the sites of the leveling biopsy more accurately especially in cases of long type intestinal aganglionosis carrying RET gene mutation.

Colon↗
PubMed2006

Root-knot nematode (Meloidogyne spp.) Me resistance genes in pepper (Capsicum annuum L.) are clustered on the P9 chromosome.

The root-knot nematode (Meloidogyne spp.) is a major plant pathogen, affecting several solanaceous crops worldwide. In Capsicum annuum, resistance to this pathogen is controlled by several independent dominant genes--the Me genes. Six Me genes have previously been shown to be stable at high temperature in three highly resistant and genetically distant accessions: PI 322719, PI 201234, and CM334 (Criollo de Morelos 334). Some genes (Me4, Mech1, and Mech2) are specific to certain Meloidogyne species or populations, whereas others (Me1, Me3, and Me7) are effective against a wide range of Meloidogyne species, including M. arenaria, M. javanica, and M. incognita, the most common species in Mediterranean and tropical areas. These genes direct different response patterns in root cells depending on the pepper line and nematode species. Allelism tests and fine mapping using the BSA-AFLP approach showed these genes to be different but linked, with a recombination frequency of 0.02-0.18. Three of the PCR-based markers identified in several genetic backgrounds were common to the six Me genes. Comparative mapping with CarthaGene software indicated that these six genes clustered in a single genomic region within a 28 cM interval. Four markers were used to anchor this cluster on the P9 chromosome on an intraspecific reference map for peppers. Other disease resistance factors have earlier been mapped in the vicinity of this cluster. This genomic area is colinear to chromosome T12 of tomato and chromosome XII of potato. Four other nematode resistance genes have earlier been identified in this area, suggesting that these nematode resistance genes are located in orthologous genomic regions in Solanaceae.

Alleles↗
PubMed2000

Functional association of CTCF with the insulator upstream of the H19 gene is parent of origin-specific and methylation-sensitive.

In mammals, a subset of genes inherit gametic marks that establish parent of origin-dependent expression patterns in the soma ([1] and references therein). The currently most extensively studied examples of this phenomenon, termed genomic imprinting, are the physically linked Igf2 (insulin-like growth factor II) and H19 genes, which are expressed mono-allelically from opposite parental alleles [1] [2]. The repressed status of the maternal Igf2 allele is due to cis elements that prevent the H19 enhancers [3] from accessing the Igf2 promoters on the maternal chromosome [4] [5]. A differentially methylated domain (DMD) in the 5' flank of H19 is maintained paternally methylated and maternally unmethylated [6] [7]. We show here by gel-shift and chromatin immunopurification analyses that binding of the highly conserved multivalent factor CTCF ([8] [9] and references therein) to the H19 DMD is methylation-sensitive and parent of origin-dependent. Selectively mutating CTCF-contacting nucleotides, which were identified by methylation interference within the extended binding sites initially revealed by nuclease footprinting, abrogated the H19 DMD enhancer-blocking property. These observations suggest that molecular mechanisms of genomic imprinting may use an unusual ability of CTCF to interact with a diverse spectrum of variant target sites, some of which include CpGs that are responsible for methylation-sensitive CTCF binding in vitro and in vivo.

Animals↗
PubMed1999

Eco Cyc: encyclopedia of Escherichia coli genes and metabolism.

The EcoCyc database describes the genome and gene products of Escherichia coli, its metabolic and signal-transduction pathways, and its tRNAs. The database describes 4391 genes of E.coli, 695 enzymes encoded by a subset of these genes, 904 metabolic reactions that occur in E.coli, and the organization of these reactions into 129 metabolic pathways. The EcoCyc graphical user interface allows scientists to query and explore the EcoCyc database using visualization tools such as genomic-map browsers and automatic layouts of metabolic pathways. EcoCyc has many references to the primary literature, and is a (qualitative) computational model of E. coli metabolism. EcoCyc is available at URL http://ecocyc. PangeaSystems.com/ecocyc/

Classification↗
PubMed2006

GENCODE: producing a reference annotation for ENCODE.

BACKGROUND: The GENCODE consortium was formed to identify and map all protein-coding genes within the ENCODE regions. This was achieved by a combination of initial manual annotation by the HAVANA team, experimental validation by the GENCODE consortium and a refinement of the annotation based on these experimental results. RESULTS: The GENCODE gene features are divided into eight different categories of which only the first two (known and novel coding sequence) are confidently predicted to be protein-coding genes. 5' rapid amplification of cDNA ends (RACE) and RT-PCR were used to experimentally verify the initial annotation. Of the 420 coding loci tested, 229 RACE products have been sequenced. They supported 5' extensions of 30 loci and new splice variants in 50 loci. In addition, 46 loci without evidence for a coding sequence were validated, consisting of 31 novel and 15 putative transcripts. We assessed the comprehensiveness of the GENCODE annotation by attempting to validate all the predicted exon boundaries outside the GENCODE annotation. Out of 1,215 tested in a subset of the ENCODE regions, 14 novel exon pairs were validated, only two of them in intergenic regions. CONCLUSION: In total, 487 loci, of which 434 are coding, have been annotated as part of the GENCODE reference set available from the UCSC browser. Comparison of GENCODE annotation with RefSeq and ENSEMBL show only 40% of GENCODE exons are contained within the two sets, which is a reflection of the high number of alternative splice forms with unique exons annotated. Over 50% of coding loci have been experimentally verified by 5' RACE for EGASP and the GENCODE collaboration is continuing to refine its annotation of 1% human genome with the aid of experimental validation.

Chromosome Mapping↗
PubMed2026

Temporal Transcriptomic Profiling of NMBA-Induced Rat Esophageal Squamous Carcinogenesis Identifies Early Inflammatory Activation and Late NRF2-Associated Oxidative-Stress Remodeling.

Temporal molecular events during early esophageal squamous carcinogenesis remain incompletely defined, in part because human precursor tissues are difficult to obtain sequentially. We used the N-nitrosomethylbenzylamine (NMBA)-induced rat model to characterize stage-associated transcriptional programs during esophageal squamous carcinogenesis. Vehicle-control reference esophageal tissues and NMBA-treated esophageal tissues, collected at weeks 6 and 29, were profiled using Affymetrix Rat Genome 230 2.0 arrays, followed by pathway analysis and qRT-PCR validation of selected genes. Relative to vehicle-control reference tissues, 173 genes were differentially expressed at week 6, whereas 1628 genes were differentially expressed at week 29, indicating marked expansion of transcriptional dysregulation during carcinogenic progression. Sixteen genes were differentially expressed only at week 6, while 157 genes were altered at both time points. Pathway analysis suggested that inflammatory and immunologic processes were prominent during the early response to NMBA exposure, whereas late-stage carcinogenesis was characterized by NRF2-associated oxidative-stress response and dysregulation of multiple glutathione S-transferase family members. A subset of progression-associated genes, including Defb4, Gsta2, Sbsn, Spink5, Plcd4, Hbb, and Hba-a2, showed increasing dysregulation from week 6 to week 29. These findings define temporally distinct molecular programs in NMBA-induced esophageal squamous carcinogenesis and provide a framework for prioritizing candidate pathways and genes relevant to esophageal cancer prevention, early detection, and progression biology.

Animals↗
PubMedDate not supplied

An autosomal genetic linkage map of the chicken.

We have developed an autosomal genetic linkage map of the chicken genome using a subpanel of 52 DNAs from a previously described reference backcross mapping population. The population derived from a cross of an inbred Red Jungle Fowl male and a highly inbred White Leghorn female. The backcross subpanel used was made up of offspring of a single F1 male with four White Leghorn females. Ninety-eight markers consisting of classical and erythrocyte antigen genes, restriction fragment length polymorphisms, random amplified polymorphic DNA, and chicken CR1 repeat-element polymorphisms were typed. Seventy-two of these markers were resolved into 19 linkage groups. Four of the linkage groups were assigned to chromosomes 1, 4, and 17. Four linkage groups were associated with linkage groups published earlier. Linkages within approximately 27 cM can be detected with a lod score of 3 with the panel used. The preliminary map contains approximately 590 cM within the linkage groups, and approximately 70% of the randomly selected markers fell in one of the groups; however, a considerable portion of the genome may remain outside of the existing linkage groups. These markers greatly expand the existing linkage map of the chicken genome.

Animals↗
PubMed1990

Structure of the human genomic region homologous to the bovine prochymosin-encoding gene.

Two human genomic libraries were probed with bovine prochymosin (bPC) cDNA. Recombinant clones covering a genomic region homologous to the entire coding region and flanking sequences of the bPC gene were isolated. Human sequences homologous to exons of the bPC gene are distributed in a DNA fragment of 10 kb. Alignment of the human sequences and the exons of bPC reveals that the human 'exons' 1-3, 5 and 7-9 have sizes identical to the corresponding bovine exons, but a nucleotide (nt) has been deleted in the human exon 4 and two nt in the human exon 6. The aligned human sequence and the coding part of bPC gene share 82% nt homology, the value ranging, in separate exons, from 76 (exon 1) to 84% (exons 5 and 6). 150 bp of 5'-flanking sequence of the human gene has 75% homology to the corresponding region of bPC gene and contains a TATA-box in a similar position. A 1-nt deletion in the human exon 4 would shift the translational reading frame of a putative human PC mRNA relative to bPC mRNA, and result in an in-phase terminator spanning codons 163 and 164 in bPC mRNA. Another terminator in-phase with the amino-acid sequence encoded by the bPC gene occurs in the human exon 5 and the second frameshift mutation in exon 6. Thus, the nt sequence analysis of the human genomic region has revealed the presence of mutations that have rendered it unable to produce a full-length protein homologous to bPC and, therefore, we refer to this gene as a human prochymosin pseudogene (hPC psi). Blot-hybridization analysis of human genomic DNA indicates that hPC psi is a single gene in the human genome.

Amino Acid Sequence↗