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Genome: The genetic complement of an organism, including all of its GENES, as represented in its DNA, or in some cases, its RNA.Protozoan Infections: Infections with unicellular organisms formerly members of the subkingdom Protozoa.Genome, Bacterial: The genetic complement of a BACTERIA as represented in its DNA.Genome, Viral: The complete genetic complement contained in a DNA or RNA molecule in a virus.Genome, Plant: The genetic complement of a plant (PLANTS) as represented in its DNA.Genome, Human: The complete genetic complement contained in the DNA of a set of CHROMOSOMES in a HUMAN. The length of the human genome is about 3 billion base pairs.Protozoan Proteins: Proteins found in any species of protozoan.Genome, Protozoan: The complete genetic complement contained in a set of CHROMOSOMES in a protozoan.Eukaryota: One of the three domains of life (the others being BACTERIA and ARCHAEA), also called Eukarya. These are organisms whose cells are enclosed in membranes and possess a nucleus. They comprise almost all multicellular and many unicellular organisms, and are traditionally divided into groups (sometimes called kingdoms) including ANIMALS; PLANTS; FUNGI; and various algae and other taxa that were previously part of the old kingdom Protista.DNA, Protozoan: Deoxyribonucleic acid that makes up the genetic material of protozoa.Ciliophora: A phylum of EUKARYOTES characterized by the presence of cilia at some time during the life cycle. It comprises three classes: KINETOFRAGMINOPHOREA; OLIGOHYMENOPHOREA; and POLYMENOPHOREA.Genome, Mitochondrial: The genetic complement of MITOCHONDRIA as represented in their DNA.Genes, Protozoan: The functional hereditary units of protozoa.RNA, Protozoan: Ribonucleic acid in protozoa having regulatory and catalytic roles as well as involvement in protein synthesis.Genome, Fungal: The complete gene complement contained in a set of chromosomes in a fungus.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Genome Size: The amount of DNA (or RNA) in one copy of a genome.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Genome, Archaeal: The genetic complement of an archaeal organism (ARCHAEA) as represented in its DNA.Protozoan Infections, Animal: Infections with unicellular organisms formerly members of the subkingdom Protozoa. The infections may be experimental or veterinary.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Genome, Insect: The genetic complement of an insect (INSECTS) as represented in its DNA.Genomics: The systematic study of the complete DNA sequences (GENOME) of organisms.Entamoeba histolytica: A species of parasitic protozoa causing ENTAMOEBIASIS and amebic dysentery (DYSENTERY, AMEBIC). Characteristics include a single nucleus containing a small central karyosome and peripheral chromatin that is finely and regularly beaded.Giardia lamblia: A species of parasitic EUKARYOTES that attaches itself to the intestinal mucosa and feeds on mucous secretions. The organism is roughly pear-shaped and motility is somewhat erratic, with a slow oscillation about the long axis.Trypanosoma cruzi: The agent of South American trypanosomiasis or CHAGAS DISEASE. Its vertebrate hosts are man and various domestic and wild animals. Insects of several species are vectors.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Genome, Chloroplast: The genetic complement of CHLOROPLASTS as represented in their DNA.Chromosome Mapping: Any method used for determining the location of and relative distances between genes on a chromosome.Leishmania: A genus of flagellate protozoa comprising several species that are pathogenic for humans. Organisms of this genus have an amastigote and a promastigote stage in their life cycles. As a result of enzymatic studies this single genus has been divided into two subgenera: Leishmania leishmania and Leishmania viannia. Species within the Leishmania leishmania subgenus include: L. aethiopica, L. arabica, L. donovani, L. enrietti, L. gerbilli, L. hertigi, L. infantum, L. major, L. mexicana, and L. tropica. The following species are those that compose the Leishmania viannia subgenus: L. braziliensis, L. guyanensis, L. lainsoni, L. naiffi, and L. shawi.Toxoplasma: A genus of protozoa parasitic to birds and mammals. T. gondii is one of the most common infectious pathogenic animal parasites of man.Alveolata: A group of three related eukaryotic phyla whose members possess an alveolar membrane system, consisting of flattened membrane-bound sacs lying beneath the outer cell membrane.Apicomplexa: A phylum of unicellular parasitic EUKARYOTES characterized by the presence of complex apical organelles generally consisting of a conoid that aids in penetrating host cells, rhoptries that possibly secrete a proteolytic enzyme, and subpellicular microtubules that may be related to motility.Trypanosoma brucei brucei: A hemoflagellate subspecies of parasitic protozoa that causes nagana in domestic and game animals in Africa. It apparently does not infect humans. It is transmitted by bites of tsetse flies (Glossina).Tetrahymena pyriformis: A species of ciliate protozoa used extensively in genetic research.Trypanosoma: A genus of flagellate protozoans found in the blood and lymph of vertebrates and invertebrates, both hosts being required to complete the life cycle.Kinetoplastida: An order of flagellate protozoa. Characteristics include the presence of one or two flagella arising from a depression in the cell body and a single mitochondrion that extends the length of the body.Antiprotozoal Agents: Substances that are destructive to protozoans.Open Reading Frames: A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR).Trypanosomatina: A suborder of monoflagellate parasitic protozoa that lives in the blood and tissues of man and animals. Representative genera include: Blastocrithidia, Leptomonas, CRITHIDIA, Herpetomonas, LEISHMANIA, Phytomonas, and TRYPANOSOMA. Species of this suborder may exist in two or more morphologic stages formerly named after genera exemplifying these forms - amastigote (LEISHMANIA), choanomastigote (CRITHIDIA), promastigote (Leptomonas), opisthomastigote (Herpetomonas), epimastigote (Blastocrithidia), and trypomastigote (TRYPANOSOMA).Intestinal Diseases, Parasitic: Infections of the INTESTINES with PARASITES, commonly involving PARASITIC WORMS. Infections with roundworms (NEMATODE INFECTIONS) and tapeworms (CESTODE INFECTIONS) are also known as HELMINTHIASIS.Antigens, Protozoan: Any part or derivative of any protozoan that elicits immunity; malaria (Plasmodium) and trypanosome antigens are presently the most frequently encountered.Genome, Helminth: The genetic complement of a helminth (HELMINTHS) as represented in its DNA.Synteny: The presence of two or more genetic loci on the same chromosome. Extensions of this original definition refer to the similarity in content and organization between chromosomes, of different species for example.Parasites: Invertebrate organisms that live on or in another organism (the host), and benefit at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Trichomonas: A genus of parasitic flagellate EUKARYOTES distinguished by the presence of four anterior flagella, an undulating membrane, and a trailing flagellum.Genome, Plastid: The genetic complement of PLASTIDS as represented in their DNA.Human Genome Project: A coordinated effort of researchers to map (CHROMOSOME MAPPING) and sequence (SEQUENCE ANALYSIS, DNA) the human GENOME.Computational Biology: A field of biology concerned with the development of techniques for the collection and manipulation of biological data, and the use of such data to make biological discoveries or predictions. This field encompasses all computational methods and theories for solving biological problems including manipulation of models and datasets.Genetic Variation: Genotypic differences observed among individuals in a population.Hartmannella: A genus of free-living amoebae found in fresh water. The cysts usually pass harmlessly through the intestinal tract of man and may thus be found in feces. Occasionally, these organisms cause respiratory tract infections or generalized fatal meningoencephalitis.Leishmania major: A parasitic hemoflagellate of the subgenus Leishmania leishmania that infects man and animals and causes cutaneous leishmaniasis (LEISHMANIASIS, CUTANEOUS) of the Old World. Transmission is by Phlebotomus sandflies.Crithidia: A genus of parasitic protozoans found in the digestive tract of invertebrates, especially insects. Organisms of this genus have an amastigote and choanomastigote stage in their life cycle.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Models, Genetic: Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Rumen: The first stomach of ruminants. It lies on the left side of the body, occupying the whole of the left side of the abdomen and even stretching across the median plane of the body to the right side. It is capacious, divided into an upper and a lower sac, each of which has a blind sac at its posterior extremity. The rumen is lined by mucous membrane containing no digestive glands, but mucus-secreting glands are present in large numbers. Coarse, partially chewed food is stored and churned in the rumen until the animal finds circumstances convenient for rumination. When this occurs, little balls of food are regurgitated through the esophagus into the mouth, and are subjected to a second more thorough mastication, swallowed, and passed on into other parts of the compound stomach. (From Black's Veterinary Dictionary, 17th ed)Entamoeba: A genus of ameboid protozoa characterized by the presence of beaded chromatin on the inner surface of the nuclear membrane. Its organisms are parasitic in invertebrates and vertebrates, including humans.Trichomonas vaginalis: A species of TRICHOMONAS that produces a refractory vaginal discharge in females, as well as bladder and urethral infections in males.DNA, Viral: Deoxyribonucleic acid that makes up the genetic material of viruses.Protozoan Vaccines: Suspensions of attenuated or killed protozoa administered for the prevention or treatment of infectious protozoan disease.Gene Order: The sequential location of genes on a chromosome.Multigene Family: A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)Repetitive Sequences, Nucleic Acid: Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).Recombination, Genetic: Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.Databases, Genetic: Databases devoted to knowledge about specific genes and gene products.Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Giardiasis: An infection of the SMALL INTESTINE caused by the flagellated protozoan GIARDIA LAMBLIA. It is spread via contaminated food and water and by direct person-to-person contact.Acanthamoeba: A genus of free-living soil amoebae that produces no flagellate stage. Its organisms are pathogens for several infections in humans and have been found in the eye, bone, brain, and respiratory tract.Host-Parasite Interactions: The relationship between an invertebrate and another organism (the host), one of which lives at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.DNA Transposable Elements: Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.Conserved Sequence: A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.Leishmania donovani: A parasitic hemoflagellate of the subgenus Leishmania leishmania that infects man and animals and causes visceral leishmaniasis (LEISHMANIASIS, VISCERAL). The sandfly genera Phlebotomus and Lutzomyia are the vectors.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.RNA, Viral: Ribonucleic acid that makes up the genetic material of viruses.Chromosomes, Artificial, Bacterial: DNA constructs that are composed of, at least, a REPLICATION ORIGIN, for successful replication, propagation to and maintenance as an extra chromosome in bacteria. In addition, they can carry large amounts (about 200 kilobases) of other sequence for a variety of bioengineering purposes.Coccidiosis: Protozoan infection found in animals and man. It is caused by several different genera of COCCIDIA.Molecular Sequence Annotation: The addition of descriptive information about the function or structure of a molecular sequence to its MOLECULAR SEQUENCE DATA record.Gene Duplication: Processes occurring in various organisms by which new genes are copied. Gene duplication may result in a MULTIGENE FAMILY; supergenes or PSEUDOGENES.Cryptosporidium: A genus of coccidian parasites of the family CRYPTOSPORIDIIDAE, found in the intestinal epithelium of many vertebrates including humans.Base Composition: The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.Software: Sequential operating programs and data which instruct the functioning of a digital computer.Amoebozoa: A supergroup (some say phylum) of ameboid EUKARYOTES, comprising ARCHAMOEBAE; LOBOSEA; and MYCETOZOA.Bacteria: One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.Cryptosporidium parvum: A species of parasitic protozoa that infects humans and most domestic mammals. Its oocysts measure five microns in diameter. These organisms exhibit alternating cycles of sexual and asexual reproduction.Genes, Viral: The functional hereditary units of VIRUSES.Antibodies, Protozoan: Immunoglobulins produced in a response to PROTOZOAN ANTIGENS.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.DNA, Mitochondrial: Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Spores, Protozoan: A vegetative stage in the life cycle of sporozoan protozoa. It is characteristic of members of the phyla APICOMPLEXA and MICROSPORIDIA.Blastocystis hominis: A species of parasitic protozoa found in the intestines of humans and other primates. It was classified as a yeast in 1912. Over the years, questions arose about this designation. In 1967, many physiological and morphological B. hominis characteristics were reported that fit a protozoan classification. Since that time, other papers have corroborated this work and the organism is now recognized as a protozoan parasite of humans causing intestinal disease with potentially disabling symptoms.Theileria parva: A protozoan parasite that is the etiologic agent of East Coast fever (THEILERIASIS). Transmission is by ticks of the Physicephalus and Hyalomma genera.Legionella pneumophila: A species of gram-negative, aerobic bacteria that is the causative agent of LEGIONNAIRES' DISEASE. It has been isolated from numerous environmental sites as well as from human lung tissue, respiratory secretions, and blood.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Leishmania mexicana: A parasitic hemoflagellate of the subgenus Leishmania leishmania that infects man and animals including rodents. The Leishmania mexicana complex causes both cutaneous (LEISHMANIASIS, CUTANEOUS) and diffuse cutaneous leishmaniasis (LEISHMANIASIS, DIFFUSE CUTANEOUS) and includes the subspecies amazonensis, garnhami, mexicana, pifanoi, and venezuelensis. L. m. mexicana causes chiclero ulcer, a form of cutaneous leishmaniasis (LEISHMANIASIS, CUTANEOUS) in the New World. The sandfly, Lutzomyia, appears to be the vector.Tetrahymena: A genus of ciliate protozoa commonly used in genetic, cytological, and other research.Sarcocystosis: Infection of the striated muscle of mammals by parasites of the genus SARCOCYSTIS. Disease symptoms such as vomiting, diarrhea, muscle weakness, and paralysis are produced by sarcocystin, a toxin produced by the organism.Tetrahymena thermophila: A species of ciliate protozoa used in genetic and cytological research.Gene Transfer, Horizontal: The naturally occurring transmission of genetic information between organisms, related or unrelated, circumventing parent-to-offspring transmission. Horizontal gene transfer may occur via a variety of naturally occurring processes such as GENETIC CONJUGATION; GENETIC TRANSDUCTION; and TRANSFECTION. It may result in a change of the recipient organism's genetic composition (TRANSFORMATION, GENETIC).Nucleic Acid Hybridization: Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)Retroelements: Elements that are transcribed into RNA, reverse-transcribed into DNA and then inserted into a new site in the genome. Long terminal repeats (LTRs) similar to those from retroviruses are contained in retrotransposons and retrovirus-like elements. Retroposons, such as LONG INTERSPERSED NUCLEOTIDE ELEMENTS and SHORT INTERSPERSED NUCLEOTIDE ELEMENTS do not contain LTRs.Contig Mapping: Overlapping of cloned or sequenced DNA to construct a continuous region of a gene, chromosome or genome.Acanthamoeba castellanii: A species of free-living soil amoebae in the family Acanthamoebidae. It can cause ENCEPHALITIS and KERATITIS in humans.RNA, Ribosomal, 18S: Constituent of the 40S subunit of eukaryotic ribosomes. 18S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.Cryptosporidiosis: Intestinal infection with organisms of the genus CRYPTOSPORIDIUM. It occurs in both animals and humans. Symptoms include severe DIARRHEA.Helminths: Commonly known as parasitic worms, this group includes the ACANTHOCEPHALA; NEMATODA; and PLATYHELMINTHS. Some authors consider certain species of LEECHES that can become temporarily parasitic as helminths.DNA, Plant: Deoxyribonucleic acid that makes up the genetic material of plants.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Tritrichomonas: A genus of flagellate EUKARYOTES possessing three long anterior flagella.Sequence Homology: The degree of similarity between sequences. Studies of AMINO ACID SEQUENCE HOMOLOGY and NUCLEIC ACID SEQUENCE HOMOLOGY provide useful information about the genetic relatedness of genes, gene products, and species.Viral Proteins: Proteins found in any species of virus.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Expressed Sequence Tags: Partial cDNA (DNA, COMPLEMENTARY) sequences that are unique to the cDNAs from which they were derived.Chromosomes: In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Eimeria: A genus of protozoan parasites of the subclass COCCIDIA. Various species are parasitic in the epithelial cells of the liver and intestines of man and other animals.Parasitic Diseases: Infections or infestations with parasitic organisms. They are often contracted through contact with an intermediate vector, but may occur as the result of direct exposure.Toxoplasmosis: The acquired form of infection by Toxoplasma gondii in animals and man.Bacterial Proteins: Proteins found in any species of bacterium.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Sarcocystis: A genus of protozoa found in reptiles, birds, and mammals, including humans. This heteroxenous parasite produces muscle cysts in intermediate hosts such as domestic herbivores (cattle, sheep, pigs) and rodents. Final hosts are predators such as dogs, cats, and man.Gene Expression Profiling: The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.Databases, Nucleic Acid: Databases containing information about NUCLEIC ACIDS such as BASE SEQUENCE; SNPS; NUCLEIC ACID CONFORMATION; and other properties. Information about the DNA fragments kept in a GENE LIBRARY or GENOMIC LIBRARY is often maintained in DNA databases.Genes, Bacterial: The functional hereditary units of BACTERIA.Chagas Disease: Infection with the protozoan parasite TRYPANOSOMA CRUZI, a form of TRYPANOSOMIASIS endemic in Central and South America. It is named after the Brazilian physician Carlos Chagas, who discovered the parasite. Infection by the parasite (positive serologic result only) is distinguished from the clinical manifestations that develop years later, such as destruction of PARASYMPATHETIC GANGLIA; CHAGAS CARDIOMYOPATHY; and dysfunction of the ESOPHAGUS or COLON.Chromosomes, Plant: Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of PLANTS.Entamoebiasis: Infection with amoebae of the genus ENTAMOEBA. Infection with E. histolytica causes DYSENTERY, AMEBIC and LIVER ABSCESS, AMEBIC.Paramecium: A genus of ciliate protozoa that is often large enough to be seen by the naked eye. Paramecia are commonly used in genetic, cytological, and other research.Genetic Markers: A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.High-Throughput Nucleotide Sequencing: Techniques of nucleotide sequence analysis that increase the range, complexity, sensitivity, and accuracy of results by greatly increasing the scale of operations and thus the number of nucleotides, and the number of copies of each nucleotide sequenced. The sequencing may be done by analysis of the synthesis or ligation products, hybridization to preexisting sequences, etc.Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.Crithidia fasciculata: A species of monogenetic, parasitic protozoa usually found in insects.Pseudogenes: Genes bearing close resemblance to known genes at different loci, but rendered non-functional by additions or deletions in structure that prevent normal transcription or translation. When lacking introns and containing a poly-A segment near the downstream end (as a result of reverse copying from processed nuclear RNA into double-stranded DNA), they are called processed genes.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.Physical Chromosome Mapping: Mapping of the linear order of genes on a chromosome with units indicating their distances by using methods other than genetic recombination. These methods include nucleotide sequencing, overlapping deletions in polytene chromosomes, and electron micrography of heteroduplex DNA. (From King & Stansfield, A Dictionary of Genetics, 5th ed)Theileriasis: Infection of cattle, sheep, or goats with protozoa of the genus THEILERIA. This infection results in an acute or chronic febrile condition.Leishmania tropica: A parasitic hemoflagellate of the subgenus Leishmania leishmania that infects man and rodents. This taxonomic complex includes species which cause a disease called Oriental sore which is a form of cutaneous leishmaniasis (LEISHMANIASIS, CUTANEOUS) of the Old World.Life Cycle Stages: The continuous sequence of changes undergone by living organisms during the post-embryonic developmental process, such as metamorphosis in insects and amphibians. This includes the developmental stages of apicomplexans such as the malarial parasite, PLASMODIUM FALCIPARUM.Plasmodium: A genus of protozoa that comprise the malaria parasites of mammals. Four species infect humans (although occasional infections with primate malarias may occur). These are PLASMODIUM FALCIPARUM; PLASMODIUM MALARIAE; PLASMODIUM OVALE, and PLASMODIUM VIVAX. Species causing infection in vertebrates other than man include: PLASMODIUM BERGHEI; PLASMODIUM CHABAUDI; P. vinckei, and PLASMODIUM YOELII in rodents; P. brasilianum, PLASMODIUM CYNOMOLGI; and PLASMODIUM KNOWLESI in monkeys; and PLASMODIUM GALLINACEUM in chickens.Symbiosis: The relationship between two different species of organisms that are interdependent; each gains benefits from the other or a relationship between different species where both of the organisms in question benefit from the presence of the other.Ciliophora Infections: Infections with protozoa of the phylum CILIOPHORA.Virus Replication: The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.Leishmania infantum: A parasitic hemoflagellate of the subgenus Leishmania leishmania that infects man and animals and causes visceral leishmaniasis (LEISHMANIASIS, VISCERAL). Human infections are confined almost entirely to children. This parasite is commonly seen in dogs, other Canidae, and porcupines with humans considered only an accidental host. Transmission is by Phlebotomus sandflies.Euplotes: A genus of ciliate protozoa having a dorsoventrally flattened body with widely spaced rows of short bristle-like cilia on the dorsal surface.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.ArtiodactylaBlotting, Southern: A method (first developed by E.M. Southern) for detection of DNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Genomic Instability: An increased tendency of the GENOME to acquire MUTATIONS when various processes involved in maintaining and replicating the genome are dysfunctional.Parasitology: The study of parasites and PARASITIC DISEASES.Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Cluster Analysis: A set of statistical methods used to group variables or observations into strongly inter-related subgroups. In epidemiology, it may be used to analyze a closely grouped series of events or cases of disease or other health-related phenomenon with well-defined distribution patterns in relation to time or place or both.Polyploidy: The chromosomal constitution of a cell containing multiples of the normal number of CHROMOSOMES; includes triploidy (symbol: 3N), tetraploidy (symbol: 4N), etc.Dientamoeba: A genus of minute EUKARYOTES that are characterized by the preponderance of binucleate over uninucleate forms, the presence of several distinct granules in the karyosome, and the lack of a cystic stage. It is parasitic in the large intestine of humans and certain monkeys.Gene Library: A large collection of DNA fragments cloned (CLONING, MOLECULAR) from a given organism, tissue, organ, or cell type. It may contain complete genomic sequences (GENOMIC LIBRARY) or complementary DNA sequences, the latter being formed from messenger RNA and lacking intron sequences.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Genes, Plant: The functional hereditary units of PLANTS.Leishmaniasis: A disease caused by any of a number of species of protozoa in the genus LEISHMANIA. There are four major clinical types of this infection: cutaneous (Old and New World) (LEISHMANIASIS, CUTANEOUS), diffuse cutaneous (LEISHMANIASIS, DIFFUSE CUTANEOUS), mucocutaneous (LEISHMANIASIS, MUCOCUTANEOUS), and visceral (LEISHMANIASIS, VISCERAL).Oligonucleotide Array Sequence Analysis: Hybridization of a nucleic acid sample to a very large set of OLIGONUCLEOTIDE PROBES, which have been attached individually in columns and rows to a solid support, to determine a BASE SEQUENCE, or to detect variations in a gene sequence, GENE EXPRESSION, or for GENE MAPPING.Genes: A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.Trypanocidal Agents: Agents destructive to the protozoal organisms belonging to the suborder TRYPANOSOMATINA.Genome, Microbial: The genetic complement of a microorganism as represented in its DNA or in some microorganisms its RNA.Macronucleus: The larger of two types of nuclei in ciliate protozoans. It is the transcriptionally active nucleus of the vegetative cells as distinguished from the smaller transcriptionally inert GERMLINE MICRONUCLEUS.Helminthiasis: Infestation with parasitic worms of the helminth class.Genome Components: The parts of a GENOME sequence that are involved with the different functions or properties of genomes as a whole as opposed to those of individual GENES.DNA Replication: The process by which a DNA molecule is duplicated.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Trichomonadida: An order of parasitic EUKARYOTES typically having four to six flagella. True cysts are known in very few species. Trichomonadida were formerly members of the class Zoomastigophora in the old five kingdom paradigm.DNA Restriction Enzymes: Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.Mutagenesis, Insertional: Mutagenesis where the mutation is caused by the introduction of foreign DNA sequences into a gene or extragenic sequence. This may occur spontaneously in vivo or be experimentally induced in vivo or in vitro. Proviral DNA insertions into or adjacent to a cellular proto-oncogene can interrupt GENETIC TRANSLATION of the coding sequences or interfere with recognition of regulatory elements and cause unregulated expression of the proto-oncogene resulting in tumor formation.Virulence: The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.Gene Dosage: The number of copies of a given gene present in the cell of an organism. An increase in gene dosage (by GENE DUPLICATION for example) can result in higher levels of gene product formation. GENE DOSAGE COMPENSATION mechanisms result in adjustments to the level GENE EXPRESSION when there are changes or differences in gene dosage.Oryza sativa: Annual cereal grass of the family POACEAE and its edible starchy grain, rice, which is the staple food of roughly one-half of the world's population.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Cyclospora: A genus of coccidian parasites in the family EIMERIIDAE. Cyclospora cayetanensis is pathogenic in humans, probably transmitted via the fecal-oral route, and causes nausea and diarrhea.Codon: A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal (CODON, TERMINATOR). Most codons are universal, but some organisms do not produce the transfer RNAs (RNA, TRANSFER) complementary to all codons. These codons are referred to as unassigned codons (CODONS, NONSENSE).RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.DNA, Intergenic: Any of the DNA in between gene-coding DNA, including untranslated regions, 5' and 3' flanking regions, INTRONS, non-functional pseudogenes, and non-functional repetitive sequences. This DNA may or may not encode regulatory functions.Toxoplasmosis, Animal: Acquired infection of non-human animals by organisms of the genus TOXOPLASMA.Theileria annulata: A protozoan parasite causing tropical theileriasis in cattle. It is transmitted by ticks of the Hyalomma genus.Gene Deletion: A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.Genetic Linkage: The co-inheritance of two or more non-allelic GENES due to their being located more or less closely on the same CHROMOSOME.Gene Rearrangement: The ordered rearrangement of gene regions by DNA recombination such as that which occurs normally during development.Introns: Sequences of DNA in the genes that are located between the EXONS. They are transcribed along with the exons but are removed from the primary gene transcript by RNA SPLICING to leave mature RNA. Some introns code for separate genes.Micronucleus, Germline: The smaller, reproductive, transcriptionally inert nucleus in the cells of ciliate protozoans, as distinguished from the larger, vegetative, transcriptionally active MACRONUCLEUS. Micronuclei participate in MEIOSIS and autogamy during GENETIC CONJUGATION.Cell Nucleus: Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Paramecium tetraurelia: A species of ciliate protozoa. It is used in biomedical research.Polymorphism, Single Nucleotide: A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.Chromosomes, Bacterial: Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.Antiparasitic Agents: Drugs used to treat or prevent parasitic infections.Selection, Genetic: Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.Neospora: A genus of protozoan parasites of the subclass COCCIDIA. Its species are parasitic in dogs, cattle, goats, and sheep, among others. N. caninum, a species that mainly infects dogs, is intracellular in neural and other cells of the body, multiplies by endodyogeny, has no parasitophorous vacuole, and has numerous rhoptries. It is known to cause lesions in many tissues, especially the brain and spinal cord as well as abortion in the expectant mother.Amoeba: A genus of ameboid protozoa. Characteristics include a vesicular nucleus and the formation of several lodopodia, one of which is dominant at a given time. Reproduction occurs asexually by binary fission.RNA, Ribosomal: The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)