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S8600021: ==Human Idiogram - X Chromosome Diseases== Idiogram- A drawing or photograph of the chromosomes of a particular cell. * 155 million base pairs * In contrast to the Y chromosome, the X chromosome contains about 5% of the haploid genome and encodes hou

2011-07-20T01:00:28Z

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==Human Idiogram - X Chromosome Diseases==

Idiogram- A drawing or photograph of the chromosomes of a particular cell.

* 155 million base pairs
* In contrast to the Y chromosome, the X chromosome contains about 5% of the haploid genome and encodes house-keeping and specialized functions.
* Genes such as Wnt-4 and DAX-1 necessary for initiation of female pathway ovary development
* An early discovery (1961) was that in order to have correct levels of X chromosome gene/protein expression (gene dosage), females must "inactivate" a single copy of the X chromosome in each and every cell. The initiator of the X inactivation process was discovered (1991) to be regulated by a region on the inactivating X chromosome encoding an '''X''' '''i'''nactive '''s'''pecific '''t'''ranscript (XIST), that acts as RNA and does not encode a protein.
* The genetic content of the X chromosome has been strongly conserved between species because these genes have become adapted to working as a single dose - Ohno's law
* X inactivation occurs randomly throughout the embryo, generating a mosaic of maternal and paternally derived X chromosome activity in all tissues and organs. This can be seen in the fur colour of tortoiseshell cats.

:'''Links:''' [http://www.ncbi.nlm.nih.gov/mapview/maps.cgi?taxid=9606&chr=X Genome View - X chromosome] | [http://www.ensembl.org/Homo_sapiens/Location/Chromosome?r=X:81932856-82032856 Ensembl - X chromosome] | [http://www.ncbi.nlm.nih.gov/omim/314670 OMIM - Xist]

{{Human chromosomes}}

[[Category:Genetics]] [[Category:Chromosome]] [[Category:Molecular]] [[Category:Cartoon]]

File:Human idiogram- X chromosome diseases.jpg - Revision history

S8600021: uploaded a new version of "File:Human idiogram- X chromosome diseases.jpg"

S8600021: uploaded a new version of "File:Human idiogram- X chromosome diseases.jpg"

S8600021: ==Human Idiogram - X Chromosome Diseases== Idiogram- A drawing or photograph of the chromosomes of a particular cell. * 155 million base pairs * In contrast to the Y chromosome, the X chromosome contains about 5% of the haploid genome and encodes hou