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Home >> Molecular Biology Dictionary >> Primordium - Processed pseudo gene
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Primordium
A group of cells which gives rise to an organ.
Primosome
A protein-replication complex that catalyses the initiation of synthesis of sunthesis of Okazaki fragments during discontinuous replication of DNA. It involves DNA primase and DNA helicase activities.
Prion
See proteinaceous infectious particle.
Proband
The individual a family in whom an inherited trait is first identified.
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Probe
1. For diagnostic tests, the agent that is used to detect the presence of a molecule in a sample.
2. A DNA or RNA sequence labelled or marked with a radioactive isotope or that is used to detect the presence of a complementary sequence by hybridization with a. nucleic acid sample.
Processed pseudo-gene
A copy of a functional gene which has no promoter, no introns and which, consequently, is not itself transcribed. Pseudo genes are thought to originate from the integration into the gene of cDNA copies synthesized from mRNA molecules by reverse transcriptase. Pseudo-genes therefore have a poly (dA) sequence at their 5' ends. Because they are not subject to any evolutionary pressure to maintain their coding potential, pseudo-genes accumulate mutations' and often have stop codons in all three reading frames
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3. A fragment f DNA or RNA which is labeled in some way (often incorporating 32P or 355), and which is used to hybridize with the nucleic acid in which you are interested.
For example, if you want to quantitate the levels of alpha subunit mRNA in a preparation of pituitary RNA, you might make a radiolabeled A in-vitro which is complementary to the mRNA, and then use, it to probe a Northern blot of the pit RNA probe can be radiolabeled, or tagged with another functional group such as biotin. A probe can be cloned DNA, or might be synthetic DNA strand.
As an example of the latter, perhaps you have isolated a protein for which you wish to obtain a DA or genomic clone. You might (pay to) microsequence a portion of the protein, deduce the nucleic acid sequence, ( ay to) synthesize an oligonucleotide carrying that sequence, radiolabel it and use it as a probe to screen a cDNA library r genomic library. A better way is to call up someone who already has the clone
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Probe DNA
A labelled DNA molecule used to detect complementary-sequence nucleic acid molecules by molecular hybridization. To localize the probe DNA sequence and reveal the complementary hybridization sequence, autoradiography or fluorescence is used. See multilocus probe; nucleotide.
Procambium
(L. pro, before + cambium) A primary meristem that gives rise to primary vascular tissues and, in most woody plants, to the vascular cambium.
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Procaryotic organisms
Organisms which do not have a cellular membrane.
Procaryote; procaryotic
See prokaryote; prokaryotic.
Processing
The reactions occurring in the nucleus which convert the primaryRNA transcript to a mature mRNA. Processing reactions include capping, splicing and polyadenylation. The term can also refer to the processing of the protein product, including proteolytic cleavages, glycosylation, etc.
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Production environment
In AnGR: All input-output relationships, over time, at a particular location. The relationships will include biological, climatic, economic, social, cultural and political factors, which combine to determine the productive potential of a particular livestock enterprise.
high-input production environment A production environment where all rate-limiting inputs to animal production can be managed to ensure high levels of survival, reproduction and output. Output and production risks are constrained primarily by managerial decisions. (Source: FAO, 1999)
medium-input production environment A production environment where management of the available resources has the scope to overcome the negative effects of the environment on animal production, although it is common for one or more factors to limit output, survival or reproduction in a serious fashion. (Source: FAO, 1999)low-input product on environment A production environment where one or more rate-limiting inputs impose continuous or variable severe pressure on livestock, resulting in low survival, reproductive rate or output. Output and production risks are exposed to major influences which may go beyond human management capacity. (source: FAO, 1999) production traits In AnGR:
Characteristics of animals, such as the quantity or quality of the milk, meat, fibre, egg, draught, etc., they (or their progeny) produce, which contribute directly to the value of the animals for the farmer, and that are identifiable or measurable at the individual level. Production traits of farm animals ate generally quantitatively inherited, i.e., they are influenced by many genes whose expression in a particular animal also reflects environmental influences.
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