X-inactivation

ly·on·i·za·tion

(lī'on-i-zā'shŭn), The normal phenomenon that wherever there are two or more haploid sets of X-linked genes in each cell all but one of the genes are inactivated apparently at random and have no phenotypic expression. Lyonization is usual but not invariable for all loci. Its randomness explains the more variable espressivity of X-linked traits in women than in men. Lyonization occurs in men with the Klinefelter (XXY) karyotype.
See also: gene dosage compensation. Synonym(s): Lyon hypothesis, X inactivation, X-inactivation [M. Lyon]

ly·on·i·za·tion

(lī'on-ī-zā'shŭn) The normal phenomenon whereby wherever there are two or more haploid sets of X-linked genes in each cell, all but one of the genes are inactivated apparently at random and have no phenotypic expression. Its randomness explains the more variable expressivity of X-linked traits in women than in men.
See also: gene dosage compensation
Synonym(s): Lyon hypothesis, X-inactivation. [M. Lyon]

X-inactivation

The normal failure of expression of one of the two X chromosomes in females. Early in development some cells switch off the paternal X chromosome, other cells switch off the maternal one. Inactivated chromosomes remains so in all subsequent daughter cells. Most women have a mixture of two different cells populations each expressing a different X chromosome. The inactivated chromosome is visible microscopically as the Barr body. This effect, sometimes called Lyonization after the British geneticism Mary Frances Lyon (1925-), who proposed it in 1961, accounts for a number of observed phenomena in genetics.

Lyon,

Mary F., English cytogeneticist, 1925–. Lyon hypothesis - Synonym(s): lyonizationlyonization - the normal phenomenon that wherever there are two or more haploid sets of X-linked genes in each cell, all but one of the genes are inactivated, apparently at random, and have no phenotypic expression. Synonym(s): Lyon hypothesis; X-inactivation

单词	x-inactivation
释义	EncyclopediaSeeLyon hypothesis X-inactivation ly·on·i·za·tion (lī'on-i-zā'shŭn), The normal phenomenon that wherever there are two or more haploid sets of X-linked genes in each cell all but one of the genes are inactivated apparently at random and have no phenotypic expression. Lyonization is usual but not invariable for all loci. Its randomness explains the more variable espressivity of X-linked traits in women than in men. Lyonization occurs in men with the Klinefelter (XXY) karyotype. See also: gene dosage compensation. Synonym(s): Lyon hypothesis, X inactivation, X-inactivation [M. Lyon] ly·on·i·za·tion (lī'on-ī-zā'shŭn) The normal phenomenon whereby wherever there are two or more haploid sets of X-linked genes in each cell, all but one of the genes are inactivated apparently at random and have no phenotypic expression. Its randomness explains the more variable expressivity of X-linked traits in women than in men. See also: gene dosage compensation Synonym(s): Lyon hypothesis, X-inactivation. [M. Lyon] X-inactivation The normal failure of expression of one of the two X chromosomes in females. Early in development some cells switch off the paternal X chromosome, other cells switch off the maternal one. Inactivated chromosomes remains so in all subsequent daughter cells. Most women have a mixture of two different cells populations each expressing a different X chromosome. The inactivated chromosome is visible microscopically as the Barr body. This effect, sometimes called Lyonization after the British geneticism Mary Frances Lyon (1925-), who proposed it in 1961, accounts for a number of observed phenomena in genetics. Lyon, Mary F., English cytogeneticist, 1925–. Lyon hypothesis - Synonym(s): lyonizationlyonization - the normal phenomenon that wherever there are two or more haploid sets of X-linked genes in each cell, all but one of the genes are inactivated, apparently at random, and have no phenotypic expression. Synonym(s): Lyon hypothesis; X-inactivation
随便看	puggled puggree puggry puggu puggy pugh pugh syndrome pugil pugilism pugilist pugilistic pugilistical south australian fisheries research advisory board south australian fishermen's co-operative limited south australian flying disc association south australian french teachers association south australian fruit and vegetable coalition south australian german teachers association south australian government regions south australian health commission south australian health omnibus survey south australian homing pigeon association south australian housing trust south australian identity support organisation south australian industrial supplies office