Processed Pseudogene

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P r i m it i ve Ch a r a c t e r

primers are limited to a length of 7 to 12 nucleotides. These primer lengths are the same as those observed at the ends of Okazaki fragments isolated from living organisms.

Further Reading

Bambara RA, Murante RS and Hendricksen LA (1997) Enzymes and reactions at the eukaryotic DNA replication fork. Journal of Biological Chemistry 272: 4647±4650. Kornberg A and Baker TA (1992) DNA Replication, 2nd edn. New York: WH Freeman. Ogawa T and Okazaki T (1980) Discontinuous DNA Replication. Annual Review of Biochemistry 49: 421±457.

See also: DNA Polymerases; DNA Replication

Primitive Character E O Wiley Copyright ß 2001 Academic Press doi: 10.1006/rwgn.2001.1026

Primitive character is an alternative term for plesiomorphic character. Hennig, 1966 preferred the more technical term plesiomorphy and phylogeneticists usually avoid the term primitive because of its anthropomorphic connotations.

Reference

Hennig W (1966) Phylogenetic Systematics. Urbana, IL: University of Illinois Press.

See also: Plesiomorphy; Symplesiomorphy

Primosome Copyright ß 2001 Academic Press doi: 10.1006/rwgn.2001.1971

A primosome is a complex of proteins involved in the synthesis of the RNA primer sequences for DNA replication. It is comprised mainly of primase and DNA helicase, which move as a unit with the replication fork. See also: Primase

Prions See: Spongiform Encephalopathies (Transmissible), Genetic Aspects of

Prisoner's Dilemma See: Hamilton's Theory, Altruism

Probe Copyright ß 2001 Academic Press doi: 10.1006/rwgn.2001.2103

A probe is the generic term for a sequence of DNA or RNA corresponding to a gene or sequence of interest that has been labeled either radioactively or with another suitable molecule (e.g., biotin, digoxygenin, or fluoresin) which can then be detected. The probe hybridizes to the complementary nucleic acid sequence and therefore labels, identifies, or distinguishes cloned DNA, genomic DNA, viral plaques, bacterial colonies, or prepared bands on a gel that contains the gene of interest. See also: DNA Hybridization; Northern Blotting; Southern Blotting

Procentriole See: Centrioles

Processed Pseudogene Copyright ß 2001 Academic Press doi: 10.1006/rwgn.2001.1973

A processed pseudogene is an inactive gene copy that lacks introns, in contrast to the interrupted structure of the active gene. Such genes may originate by reverse transcription of mRNA and insertion of a duplex copy into the genome. See also: Pseudogene

Progeny Testing I Ruvinsky Copyright ß 2001 Academic Press doi: 10.1006/rwgn.2001.1029

Progeny testing is a method commonly used in animal selection. It relies on phenotypic assessment of an individual's offspring to make decisions regarding selection. For the traits that have high heritability simpler selection protocols (e.g., individual selection) may be