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Transib
Transib is a superfamily of interspersed repeats DNA transposons. It was named after the Trans-Siberian Express. It is similar to EnSpm/CACTA. Transib was first described in 2003, discovered in the ''Drosophila melanogaster'' genome. It usually encodes a single protein, DDE transcriptase. An intact element including terminal inverted repeats (TIR) was found in 2008 in the ''Helicoverpa zea'' genome. Divergent clades of this superfamily has since been discovered and dubbed Transib and TransibSU (for sea urchin); Chapaev and Chapaev3 of the CACTA superfamily are sometimes included too. The differences lie in the domain organization of the core transcriptase; TransibSU is also notable for having RAG2-like proteins. Transib is notable as the source of the two Recombination-activating genes. An active transposon with RAG1/2-like genes ("ProtoRAG"; ) has been discovered in ''B. belcheri '' (Chinese lancelet). The TIRs are structurally similar to Recombination signal sequences Recombinat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recombination-activating Gene
The recombination-activating genes (RAGs) encode parts of a protein complex that plays important roles in the rearrangement and recombination of the genes encoding immunoglobulin and T cell receptor molecules. There are two recombination-activating genes RAG1 and RAG2, whose cellular expression is restricted to lymphocytes during their developmental stages. The enzymes encoded by these genes, RAG-1 and RAG-2, are essential to the generation of mature B cells and T cells, two types of lymphocyte that are crucial components of the adaptive immune system. Function In the vertebrate immune system, each antibody is customized to attack one particular antigen (foreign proteins and carbohydrates) without attacking the body itself. The human genome has at most 30,000 genes, and yet it generates millions of different antibodies, which allows it to be able to respond to invasion from millions of different antigens. The immune system generates this diversity of antibodies by shuffling, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Transposon
DNA transposons are DNA sequences, sometimes referred to "jumping genes", that can move and integrate to different locations within the genome. They are class II transposable elements (TEs) that move through a DNA intermediate, as opposed to class I TEs, retrotransposons, that move through an RNA intermediate. DNA transposons can move in the DNA of an organism via a single-or double-stranded DNA intermediate. DNA transposons have been found in both prokaryotic and eukaryotic organisms. They can make up a significant portion of an organism's genome, particularly in eukaryotes. In prokaryotes, TE's can facilitate the horizontal transfer of antibiotic resistance or other genes associated with virulence. After replicating and propagating in a host, all transposon copies become inactivated and are lost unless the transposon passes to a genome by starting a new life cycle with horizontal transfer. It is important to note that DNA transposons do not randomly insert themselves into the geno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interspersed Repeat
Interspersed repetitive DNA is found in all eukaryotic genomes. They differ from tandem repeat DNA in that rather than the repeat sequences coming right after one another, they are dispersed throughout the genome and nonadjacent. The sequence that repeats can vary depending on the type of organism, and many other factors. Certain classes of interspersed repeat sequences propagate themselves by RNA mediated transposition; they have been called retrotransposons, and they constitute 25–40% of most mammalian genomes. Some types of interspersed repetitive DNA elements allow new genes to evolve by uncoupling similar DNA sequences from gene conversion during meiosis. Intrachromosomal and interchromosomal gene conversion Gene conversion acts on DNA sequence homology as its substrate. There is no requirement that the sequence homologies lie at the allelic positions on their respective chromosomes or even that the homologies lie on different chromosomes. Gene conversion events can occur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trans-Siberian Express
The Trans-Siberian Railway (TSR; , , ) connects European Russia to the Russian Far East. Spanning a length of over , it is the longest railway line in the world. It runs from the city of Moscow in the west to the city of Vladivostok in the east. During the period of the Russian Empire, government ministers—personally appointed by Alexander III and his son Nicholas II—supervised the building of the railway network between 1891 and 1916. Even before its completion, the line attracted travelers who documented their experiences. Since 1916, the Trans-Siberian Railway has directly connected Moscow with Vladivostok. , expansion projects remain underway, with connections being built to Russia's neighbors (namely Mongolia, China, and North Korea). Additionally, there have been proposals and talks to expand the network to Tokyo, Japan, with new bridges that would connect the mainland railway through the Russian island of Sakhalin and the Japanese island of Hokkaido. Route descript ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila Melanogaster
''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly" or "pomace fly". Starting with Charles W. Woodworth's 1901 proposal of the use of this species as a model organism, ''D. melanogaster'' continues to be widely used for biological research in genetics, physiology, microbial pathogenesis, and life history evolution. As of 2017, five Nobel Prizes have been awarded to drosophilists for their work using the insect. ''D. melanogaster'' is typically used in research owing to its rapid life cycle, relatively simple genetics with only four pairs of chromosomes, and large number of offspring per generation. It was originally an African species, with all non-African lineages having a common origin. Its geographic range includes all continents, including islands. ''D. melanogaster'' is a common pest in homes, restaurants, and othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicoverpa Zea
''Helicoverpa zea, ''commonly known as the corn earworm, is a species (formerly in the genus ''Heliothis'') in the family Noctuidae. The larva of the moth ''Helicoverpa zea'' is a major agricultural pest. Since it is polyphagous (feeds on many different plants) during the larval stage, the species has been given many different common names, including the cotton bollworm and the tomato fruitworm. It also consumes a wide variety of other crops. The species is widely distributed across the Americas with the exception of northern Canada and Alaska. It has become resistant to many pesticides, but can be controlled with integrated pest management techniques including deep ploughing, trap crops, chemical control using mineral oil, and biological controls. The species migrates seasonally, at night, and can be carried downwind up to 400 km. Pupae can make use of diapause to wait out adverse environmental conditions, especially at high latitudes and in drought. Distribution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recombination Signal Sequences
Recombination signal sequences are conserved sequences of noncoding DNA that are recognized by the Recombination-activating gene, RAG1/RAG2 enzyme complex during V(D)J recombination in immature B cells and T cells. Recombination signal sequences guide the enzyme complex to the V, D, and J gene segments that will undergo recombination during the formation of the Immunoglobulin heavy chain, heavy and Immunoglobulin light chain, light-chain variable regions in T-cell receptors and Immunoglobulin superfamily, immunoglobulin molecules. Structure RSSs are made up of highly conserved heptamer sequences (7 base pairs), Spacer DNA, spacer sequences, and conserved nonamer sequences (9 base pairs) that are adjacent to the V, D and J sequences in the Heavychain immunoglobulin, heavy-chain region of DNA and the V and J sequences in the Immunoglobulin light chain, light-chain DNA region. Spacer sequences are located between heptamer and nonamer sequences and exhibit base pair variety but are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psectrotarsia Flava
''Psectrotarsia flava'' is a species of moth of the family Noctuidae. It is found in Peru, west of the Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S .... The length of the forewings is 12.9–13.3 mm. External links Species info Revision of the Genus Psectrotarsia Dognin, 1907 (Lepidoptera: Noctuidae: Heliothinae) Heliothinae {{Heliothinae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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