Dosage Compensation Mechanism: Difference between revisions
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As human females have two [[X chromosome|X chromosomes]], this means they have the ability to produce twice as much X-linked gene product, this Dosage Compensation Mechanism is responsible for keeping levels of the X-linked gene product similar in both males and females. Therefore, such a mechanism only exists in females. Dosage compensation requires [[RNA polymerase|RNA polymerase]], [[Tsix transcript|Tsix transcript]] and [[Xist transcript|Xist transcript]] as well as the X chromosomes of developing embryonic cells. Note that each transcript is transcribed on one [[Chromosome|chromosome]] each. Xist acts as to ensure inactivation of X chromosome whereas Tsix ensures X chromosome remains active. Such activity is carried out from the [[X inactivation centre|X inactivation centre]] <ref>Lodish, et al. 2008. (Molecular Cell Biology) 6th edition. pg 959 Fig22-7</ref>. | As human females have two [[X chromosome|X chromosomes]], this means they have the ability to produce twice as much X-linked gene product, this Dosage Compensation Mechanism is responsible for keeping levels of the X-linked gene product similar in both males and females. Therefore, such a mechanism only exists in females. Dosage compensation requires [[RNA polymerase|RNA polymerase]], [[Tsix transcript|Tsix transcript]] and [[Xist transcript|Xist transcript]] as well as the X chromosomes of developing embryonic cells. Note that each transcript is transcribed on one [[Chromosome|chromosome]] each. Xist acts as to ensure inactivation of X chromosome whereas Tsix ensures X chromosome remains active. Such activity is carried out from the [[X inactivation centre|X inactivation centre]] <ref>Lodish, et al. 2008. (Molecular Cell Biology) 6th edition. pg 959 Fig22-7</ref>., also known as XIC. The XIC is located at the centromere and is where decativation of the X Chromosome begins<ref>Hartl.D.L, Ruvolo.M, Genetics: analysis of genes and genomes, eighth edition, Jones and Bartlett Learning, 2012 page 262</ref> This mechanism follows the process of X-inactivation, also termed [[Lyonization|Lyonization]] or single active X principle<span style="line-height: 1.5em;">, in which regardless of the amount of </span>[[X chromosomes|X chromosomes]]<span style="line-height: 1.5em;"> are present, all but one are inactivated. However, although one of the X chromosomes is said to be inactivated, there is still around 15%</span><span style="line-height: 1.5em;"> of the genes on the inactivated X chromosome which aren't inactivtaed. <ref>Whitehall Dr S.K, Genetics Lecture 13, BGM1004 lecture, accessed 27/10/14,</ref></span> | ||
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Revision as of 19:59, 25 November 2014
As human females have two X chromosomes, this means they have the ability to produce twice as much X-linked gene product, this Dosage Compensation Mechanism is responsible for keeping levels of the X-linked gene product similar in both males and females. Therefore, such a mechanism only exists in females. Dosage compensation requires RNA polymerase, Tsix transcript and Xist transcript as well as the X chromosomes of developing embryonic cells. Note that each transcript is transcribed on one chromosome each. Xist acts as to ensure inactivation of X chromosome whereas Tsix ensures X chromosome remains active. Such activity is carried out from the X inactivation centre [1]., also known as XIC. The XIC is located at the centromere and is where decativation of the X Chromosome begins[2] This mechanism follows the process of X-inactivation, also termed Lyonization or single active X principle, in which regardless of the amount of X chromosomes are present, all but one are inactivated. However, although one of the X chromosomes is said to be inactivated, there is still around 15% of the genes on the inactivated X chromosome which aren't inactivtaed. [3]