遺伝子量補償、遺伝子補正

WordNet

(psychiatry) a defense mechanism that conceals your undesirable shortcomings by exaggerating desirable behaviors
something (such as money) given or received as payment or reparation (as for a service or loss or injury)

PrepTutorEJDIC

〈U〉UC〉(…の)『償い』,代償,埋め合わせ《+『for』+『名』》 / 〈C〉〈U〉(…の)『賠償金』,補償金《+『for』+『名』》 / 〈U〉《米》報酬,給与
〈C〉《通例a~》1回分の投薬量 / 〈U〉《まれ》投薬

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/06/23 09:32:29」(JST)

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Dosage compensation, also known as Ohno's Hypothesis, is a hypothetical genetic regulatory mechanism which operates to equalize the phenotypic expression of characteristics determined by genes on the X chromosome so that they are equally expressed in the human XY male and the XX female.

Dosage compensation may occur in other organisms like the fruit fly Drosophila melanogaster, the roundworm Caenorhabditis elegans and the plant White campion (Silene latifolia).^[1]

Species can have different mechanisms of dosage compensation. In human females (XX), one chromosome is inactivated (see X-inactivation), resulting in a heterochromatic and largely genetically inactive Barr body. Drosophila males (XY) double the expression of genes along the X chromosome. In C. elegans hermaphrodites (XX), both X chromosomes are partially repressed. Any of these mechanisms results in balancing the relative gene expression between males and females (or, in the case of C. elegans, hermaphrodites and males).

In plants (which lack dimorphic sex chromosomes), dosage compensation can occur when aberrant meiotic events or mutations result in either aneuploidy or polyploidy. Genes on the affected chromosome may be upregulated or down-regulated to compensate for the change in the normal number of chromosomes present.

In Humans*: Women with two normal X chromosomes have the same blood levels of X-chromosome protein products, such as factor VIII, as normal men, who of course have only one X chromosome. An exception to this phenomenon of dosage compensation is the level of steroid sulfatase in blood, which is increased in women compared with men. Not surprisingly it has been shown that the locus for steroid sulfatase (deficiency of which causes a skin disorder known as ichthyosis) is in the pseudoautosomal region.

References[edit]

^ "Rapid de novo evolution of X chromosome dosage compensation in Silene latifolia, a plant with young sex chromosomes.". PLoS Biology. Retrieved 10 May 2012.

Turnpenny & Ellard: Emery's Elements of Medical Genetics 13E

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English Journal

When and why does sex chromosome dosage compensation evolve?

Chandler CH1.
Annals of the New York Academy of Sciences.Ann N Y Acad Sci.2017 Jan 18. doi: 10.1111/nyas.13307. [Epub ahead of print]
In many species, sex is determined by sex chromosomes, and the sex-specific chromosome (Y or W) stops recombining until it degenerates and carries fewer genes than its recombining counterpart (X or Z). This creates an imbalance in the dosage of most sex-linked genes between males and females. Early
PMID 28099765

Random X-chromosome inactivation dynamics in vivo by single-cell RNA sequencing.

Wang M1, Lin F1, Xing K1, Liu L2.
BMC genomics.BMC Genomics.2017 Jan 17;18(1):90. doi: 10.1186/s12864-016-3466-8.
BACKGROUND: Random X-chromosome inactivation (rXCI) is important for the maintenance of normal somatic cell functions in female eutherian mammals. The dynamics of X-chromosome inactivation initiation has been widely studied by assessing embryonic stem cell differentiation in vitro. To investigate th
PMID 28095777

Sexual Dimorphism of Body Size Is Controlled by Dosage of the X-Chromosomal Gene Myc and by the Sex-Determining Gene tra in Drosophila.

Wehr Mathews K1, Cavegn M2, Zwicky M2.
Genetics.Genetics.2017 Jan 6. pii: genetics.116.192260. doi: 10.1534/genetics.116.192260. [Epub ahead of print]
Drosophila females are larger than males. In this paper, we describe how X chromosome dosage drives sexual dimorphism of body size through two means: first, through unbalanced expression of a key X-linked growth regulating gene and second, through female-specific activation of the sex-determination
PMID 28064166