Difference between revisions of "X Chromosome"

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==Introduction==
 
==Introduction==
 
[[File:Human X chromosome.jpg|thumb|300px|Human X chromosome]]
 
[[File:Human X chromosome.jpg|thumb|300px|Human X chromosome]]
Humans have 23 pairs of chromosomes, 22 autosomes and a pair of sex chromosomes. Females have a pair of X chromosomes (46, XX) and males have one X and one [[Y_Chromosome|Y Chromosome]] (46, XY). This section of notes introduces the X chromosome and its role in development. There is a separate page discussing [[Molecular - X Chromosome Inactivation]] that occurs in female development to provide the correct gene dosage.
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Humans have 23 pairs of chromosomes, 22 autosomes and a pair of sex chromosomes. Females have a pair of X chromosomes (46, XX) and males have one X and one [[Y_Chromosome|Y Chromosome]] (46, XY). This section of notes introduces the X chromosome and its role in development. There is a separate page discussing [[Molecular_Development_-_X_Inactivation|X Inactivation]] that occurs in female development to provide the correct gene dosage.
  
'''Links:''' [[Y_Chromosome|Y Chromosome]] | [http://embryology.med.unsw.edu.au/Notes/genitalX.htm X Chromosome]
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:'''Links:''' [[Molecular_Development_-_X_Inactivation|X Inactivation]] | [[Y_Chromosome|Y Chromosome]] | [http://embryology.med.unsw.edu.au/Notes/genitalX.htm X Chromosome]
  
 
==X Chromosome Overview==
 
==X Chromosome Overview==

Revision as of 14:44, 31 October 2010

Introduction

Human X chromosome

Humans have 23 pairs of chromosomes, 22 autosomes and a pair of sex chromosomes. Females have a pair of X chromosomes (46, XX) and males have one X and one Y Chromosome (46, XY). This section of notes introduces the X chromosome and its role in development. There is a separate page discussing X Inactivation that occurs in female development to provide the correct gene dosage.


Links: X Inactivation | Y Chromosome | X Chromosome

X Chromosome Overview

  • 1400+ genes
  • 150 million base pairs
  • Contains about 5% of the haploid genome.
  • Genes encode house-keeping and specialized functions.
  • Conserved in gene content between species.
  • In females, one of the X-chromosomes is inactivated in each and every cell (known since 1961).
    • This inactivation occurs during embryogenesis.
    • X Inactivation appears to be random in somatic cells. (mosaic pattern)
    • The process starts at the "X inactivation centre" and spreads along the chromosome.

References

  • The DNA sequence of the human X chromosome. Ross MT, Grafham DV, Coffey AJ, Scherer S, McLay K, Muzny D, Platzer M, Howell GR, Burrows C, Bird CP, Frankish A, Lovell FL, Howe KL, Ashurst JL, Fulton RS, Sudbrak R, Wen G, Jones MC, Hurles ME, Andrews TD, Scott CE, Searle S, Ramser J, Whittaker A, Deadman R, Carter NP, Hunt SE, Chen R, Cree A, Gunaratne P, Havlak P, Hodgson A, Metzker ML, Richards S, Scott G, Steffen D, Sodergren E, Wheeler DA, Worley KC, Ainscough R, Ambrose KD, Ansari-Lari MA, Aradhya S, Ashwell RI, Babbage AK, Bagguley CL, Ballabio A, Banerjee R, Barker GE, Barlow KF, Barrett IP, Bates KN, Beare DM, Beasley H, Beasley O, Beck A, Bethel G, Blechschmidt K, Brady N, Bray-Allen S, Bridgeman AM, Brown AJ, Brown MJ, Bonnin D, Bruford EA, Buhay C, Burch P, Burford D, Burgess J, Burrill W, Burton J, Bye JM, Carder C, Carrel L, Chako J, Chapman JC, Chavez D, Chen E, Chen G, Chen Y, Chen Z, Chinault C, Ciccodicola A, Clark SY, Clarke G, Clee CM, Clegg S, Clerc-Blankenburg K, Clifford K, Cobley V, Cole CG, Conquer JS, Corby N, Connor RE, David R, Davies J, Davis C, Davis J, Delgado O, Deshazo D, Dhami P, Ding Y, Dinh H, Dodsworth S, Draper H, Dugan-Rocha S, Dunham A, Dunn M, Durbin KJ, Dutta I, Eades T, Ellwood M, Emery-Cohen A, Errington H, Evans KL, Faulkner L, Francis F, Frankland J, Fraser AE, Galgoczy P, Gilbert J, Gill R, Glöckner G, Gregory SG, Gribble S, Griffiths C, Grocock R, Gu Y, Gwilliam R, Hamilton C, Hart EA, Hawes A, Heath PD, Heitmann K, Hennig S, Hernandez J, Hinzmann B, Ho S, Hoffs M, Howden PJ, Huckle EJ, Hume J, Hunt PJ, Hunt AR, Isherwood J, Jacob L, Johnson D, Jones S, de Jong PJ, Joseph SS, Keenan S, Kelly S, Kershaw JK, Khan Z, Kioschis P, Klages S, Knights AJ, Kosiura A, Kovar-Smith C, Laird GK, Langford C, Lawlor S, Leversha M, Lewis L, Liu W, Lloyd C, Lloyd DM, Loulseged H, Loveland JE, Lovell JD, Lozado R, Lu J, Lyne R, Ma J, Maheshwari M, Matthews LH, McDowall J, McLaren S, McMurray A, Meidl P, Meitinger T, Milne S, Miner G, Mistry SL, Morgan M, Morris S, Müller I, Mullikin JC, Nguyen N, Nordsiek G, Nyakatura G, O'Dell CN, Okwuonu G, Palmer S, Pandian R, Parker D, Parrish J, Pasternak S, Patel D, Pearce AV, Pearson DM, Pelan SE, Perez L, Porter KM, Ramsey Y, Reichwald K, Rhodes S, Ridler KA, Schlessinger D, Schueler MG, Sehra HK, Shaw-Smith C, Shen H, Sheridan EM, Shownkeen R, Skuce CD, Smith ML, Sotheran EC, Steingruber HE, Steward CA, Storey R, Swann RM, Swarbreck D, Tabor PE, Taudien S, Taylor T, Teague B, Thomas K, Thorpe A, Timms K, Tracey A, Trevanion S, Tromans AC, d'Urso M, Verduzco D, Villasana D, Waldron L, Wall M, Wang Q, Warren J, Warry GL, Wei X, West A, Whitehead SL, Whiteley MN, Wilkinson JE, Willey DL, Williams G, Williams L, Williamson A, Williamson H, Wilming L, Woodmansey RL, Wray PW, Yen J, Zhang J, Zhou J, Zoghbi H, Zorilla S, Buck D, Reinhardt R, Poustka A, Rosenthal A, Lehrach H, Meindl A, Minx PJ, Hillier LW, Willard HF, Wilson RK, Waterston RH, Rice CM, Vaudin M, Coulson A, Nelson DL, Weinstock G, Sulston JE, Durbin R, Hubbard T, Gibbs RA, Beck S, Rogers J, Bentley DR. Nature. 2005 Mar 17;434(7031):325-37. PMID: 15772651
  • Extensive gene traffic on the mammalian X chromosome. Emerson JJ, Kaessmann H, Betrán E, Long M. Science. 2004 Jan 23;303(5657):537-40. PMID: 14739461