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pBR322
1428
p B R 3 22
transcription factor of the winged helix family (forkhead FKHR). All these phenotypes point to a function of Pax genes in very early steps of cell differentiation. Analysis of Pax5-deficient mice support the hypothesis that Pax genes may have a dual function in this process: activating a certain differentiation potential and thereby inhibiting inappropriate lineages. It is conceivable that Pax genes act on cell proliferation and/or survival.
Further reading
Noll M (1993) Evolution and role of Pax genes. Current Opinion Genetics and Development 3: 595±605. Mansouri A, Hallonet M and Gruss P (1996) Pax genes and their roles in cell differentiation and development. Current Opinion in Cell Biology 8: 851±857. Mansouri A, St-Onge L and Gruss P (1999) Pax genes in endoderm-derived organs. Trends in Endocrinology and Metabolism 10: 164±167.
See also: Developmental Genetics; Embryonic Development of the Nematode Caenorhabditis elegans
pBR322 Copyright ß 2001 Academic Press doi: 10.1006/rwgn.2001.1952
pBR322 is one of the standard plasmid cloning vectors. See also: Cloning Vectors
PCR See: Polymerase Chain Reaction (PCR)
Pedigree Analysis J M Connor Copyright ß 2001 Academic Press doi: 10.1006/rwgn.2001.0964
Pedigree analysis describes the process of interpretation of information displayed as a family tree. The family tree or pedigree is constructed using a standardized set of symbols and will include information about the disease status of each individual. If only a single individual is affected within the family then the pedigree cannot in itself provide proof for a particular mode of inheritance and cannot distinguish inherited
from noninherited conditions. When more than one individual is affected then the pattern may provide important clues or even proof of the mode of inheritance. There are four main patterns of inheritance that may be seen in a pedigree. A `vertical' pedigree is the term used when a trait or disease is passed down through several generations, directly from an affected individual to affected descendants in successive generations. Such vertical transmission is typically seen in autosomal dominant inheritance but can also be seen in X-linked dominant inheritance, mitochondrial inheritance, inherited chromosomal imbalances and nongenetic situations (such as infective agents). In autosomal dominant inheritance both sexes can be affected and, in turn, transmit the trait to both males and females. In Xlinked dominant inheritance both sexes can be affected and females can transmit the trait to both sons and daughters but affected males transmit it to all daughters and no sons. In mitochondrial inheritance both sexes can be affected but males do not transmit the trait and females transmit it to all offspring (although not all may be clinically affected). A `horizontal' pedigree is the term used when a trait or disease only affects family members in the same generation. This type of pedigree pattern is typical of autosomal recessive inheritance but can also be seen in X-linked recessive disorders, autosomal dominant disorders with incomplete penetrance, chromosomal translocations and nongenetic situations. In autosomal recessive inheritance both sexes can be affected in a sibship (brothers and sisters) and the disease severity is similar in males and females. Parental consanguinity (parents who are blood relatives) would be a further clue to an autosomal recessive condition. In an X-linked recessive condition only brothers are affected and in the absence of other affected male relatives (see above) this would mimic an autosomal recessive pedigree. The situation of affected brothers and sisters with normal parents might also be seen if one parent has an autosomal dominant condition but is clinically unaffected due to nonpenetrance or gonadal mosaicism. A `knight's move' pedigree is the term used when a trait or disease only affects males in a family and where affected males are related via outwardly normal females. Thus, for example, an affected boy may have an affected maternal uncle or affected maternal male cousins. The intervening females are usually clinically normal but are carrying the faulty gene. This pedigree pattern is typical of X-linked recessive inheritance. Males have only a single X chromosome and thus are affected by mutations in genes on the X, whereas the intervening females have a normal copy of the gene on their other X chromosome and are not usually affected.
p B R 3 22
transcription factor of the winged helix family (forkhead FKHR). All these phenotypes point to a function of Pax genes in very early steps of cell differentiation. Analysis of Pax5-deficient mice support the hypothesis that Pax genes may have a dual function in this process: activating a certain differentiation potential and thereby inhibiting inappropriate lineages. It is conceivable that Pax genes act on cell proliferation and/or survival.
Further reading
Noll M (1993) Evolution and role of Pax genes. Current Opinion Genetics and Development 3: 595±605. Mansouri A, Hallonet M and Gruss P (1996) Pax genes and their roles in cell differentiation and development. Current Opinion in Cell Biology 8: 851±857. Mansouri A, St-Onge L and Gruss P (1999) Pax genes in endoderm-derived organs. Trends in Endocrinology and Metabolism 10: 164±167.
See also: Developmental Genetics; Embryonic Development of the Nematode Caenorhabditis elegans
pBR322 Copyright ß 2001 Academic Press doi: 10.1006/rwgn.2001.1952
pBR322 is one of the standard plasmid cloning vectors. See also: Cloning Vectors
PCR See: Polymerase Chain Reaction (PCR)
Pedigree Analysis J M Connor Copyright ß 2001 Academic Press doi: 10.1006/rwgn.2001.0964
Pedigree analysis describes the process of interpretation of information displayed as a family tree. The family tree or pedigree is constructed using a standardized set of symbols and will include information about the disease status of each individual. If only a single individual is affected within the family then the pedigree cannot in itself provide proof for a particular mode of inheritance and cannot distinguish inherited
from noninherited conditions. When more than one individual is affected then the pattern may provide important clues or even proof of the mode of inheritance. There are four main patterns of inheritance that may be seen in a pedigree. A `vertical' pedigree is the term used when a trait or disease is passed down through several generations, directly from an affected individual to affected descendants in successive generations. Such vertical transmission is typically seen in autosomal dominant inheritance but can also be seen in X-linked dominant inheritance, mitochondrial inheritance, inherited chromosomal imbalances and nongenetic situations (such as infective agents). In autosomal dominant inheritance both sexes can be affected and, in turn, transmit the trait to both males and females. In Xlinked dominant inheritance both sexes can be affected and females can transmit the trait to both sons and daughters but affected males transmit it to all daughters and no sons. In mitochondrial inheritance both sexes can be affected but males do not transmit the trait and females transmit it to all offspring (although not all may be clinically affected). A `horizontal' pedigree is the term used when a trait or disease only affects family members in the same generation. This type of pedigree pattern is typical of autosomal recessive inheritance but can also be seen in X-linked recessive disorders, autosomal dominant disorders with incomplete penetrance, chromosomal translocations and nongenetic situations. In autosomal recessive inheritance both sexes can be affected in a sibship (brothers and sisters) and the disease severity is similar in males and females. Parental consanguinity (parents who are blood relatives) would be a further clue to an autosomal recessive condition. In an X-linked recessive condition only brothers are affected and in the absence of other affected male relatives (see above) this would mimic an autosomal recessive pedigree. The situation of affected brothers and sisters with normal parents might also be seen if one parent has an autosomal dominant condition but is clinically unaffected due to nonpenetrance or gonadal mosaicism. A `knight's move' pedigree is the term used when a trait or disease only affects males in a family and where affected males are related via outwardly normal females. Thus, for example, an affected boy may have an affected maternal uncle or affected maternal male cousins. The intervening females are usually clinically normal but are carrying the faulty gene. This pedigree pattern is typical of X-linked recessive inheritance. Males have only a single X chromosome and thus are affected by mutations in genes on the X, whereas the intervening females have a normal copy of the gene on their other X chromosome and are not usually affected.