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Twins

Twins. An ACE project by Bryan Yan 2I102. Agenda. Fraternal Twins Identical Twins Semi-Identical Twins Siamese Twins. Fraternal Twins – What?. Non-Identical Twins Small chance of having the same chromosome profile May be different sex. Fraternal – How?.

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Twins

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  1. Twins An ACE project by Bryan Yan 2I102

  2. Agenda • Fraternal Twins • Identical Twins • Semi-Identical Twins • Siamese Twins

  3. Fraternal Twins – What? • Non-Identical Twins • Small chance of having the same chromosome profile • May be different sex

  4. Fraternal – How? • Two eggs are independently fertilized by two different sperm cells • Two fertilized eggs are implanted in the uterus wall at the same time

  5. Fraternal Twins – Who? • More common for older mothers • Twinning rates doubling in mothers over the age of 35

  6. Fraternal Twins - Advances • Advent of technologies and techniques to assist women in getting pregnant has cause the rate of fraternalsto increase

  7. Identical Twins – What? • Nearly genetically identical • Same sex, unless there are mutations during development

  8. Identical Twins – How? • Single egg is fertilized to form one zygote • Then divides into two separate embryos

  9. Identical Twins – When? • Occurs approximately in every 3 out of 1000 births • For IVF, it occurs approximately in every 21 out of 1000 births

  10. Semi-Identical Twins – What? • Genetically identical maternal genes • Genetically dissimilar paternal genes

  11. Semi-Identical Twins – How? (Type 1) • Polar Twins • A sperm fertilizes the ovum while the other fertilizes the polar body • 25% genetic identity

  12. Polar Body? • Diploid cells in animals undergoing cytokinesis after meiosis to produce egg cells • Sometimes divide unevenly

  13. Polar Body? • Most of the cytoplasm is segregated into one ovum • Other smaller cells are called polar bodies

  14. Semi-Identical Twins – How? (Type 2) • Sesquizygotictwins • Twosperms fertilize one ovum • Form a triploid • Triploid splits

  15. Sesquizygotictwins • Both cells from triploid splitting embeds on the endometrium • Develop into identical twins

  16. Siamese Twins – What? • Conjoined twins • Twins whose bodies are joined at a certain part e.g. upper chest

  17. Siamese Twins – How? • Afertilized egg completely separates • But stem cells (which search for similar cells) find like-stem cells on the other twin • Fuse the twins together

  18. Siamese Twins – When? • Ranges from 1:50000 births to 1:100000 births depending on country of birth

  19. Siamese Twins – Where? • Most common in Southwest Asia and Africa

  20. Siamese Twins – Who? • More common amongst females with a 3:1 ratio

  21. References • http://en.wikipedia.org/wiki/Twin • http://www.vtaide.com/png/George/twins.htm • http://pregnancy.about.com/od/pregnancy/a/Twin-Pregnancy.htm • http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000058&ptid=17 • http://www3.telus.net/tyee/multiples/1formed.html • http://answers.yahoo.com/question/index?qid=20080511034534AAUeVEH • http://suite101.com/article/a-third-kind-of-twins-a183863 • http://multiples.about.com/cs/glossary/g/polarbody_def.htm • http://en.wikipedia.org/wiki/Polar_body • http://en.wikipedia.org/wiki/File:Gray9.png • http://en.wikipedia.org/wiki/File:Gray5.svg • http://ars.sciencedirect.com/content/image/1-s2.0-S0165460897004718-gr2.jpg • http://www.advancedfertility.com/images/ENDOCC1.JPG • http://en.wikipedia.org/wiki/Conjoined_twins • http://www.news.ku.edu/2007/may/11/images/07465_11.jpg • http://www.sciencephoto.com/image/314150/530wm/P6800902-LM_of_human_ovum_at_the_two_cell_stage-SPL.jpg • http://servinghimwithshakyhands.files.wordpress.com/2011/05/35-b-day-cake.jpg

  22. References (Continued) • http://vixstar1314.files.wordpress.com/2011/06/global-technology.jpg • http://www.twinsrealm.com/othrpics/nicoleandjaqueline.jpg • http://edu.glogster.com/media/3/12/25/45/12254586.jpg • http://blogs.telegraph.co.uk/culture/files/2010/10/ivf-getty.jpg • http://www.scientificamerican.com/media/inline/15DD5B0E-AB41-23B8-2B1E53E8573428C5_1.jpg • http://blog.f1000.com/wp-content/uploads/2011/12/090709-sperm-egg-02.jpg • http://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Chang-eng-bunker-PD.gif/230px-Chang-eng-bunker-PD.gif • http://upload.wikimedia.org/wikipedia/commons/thumb/f/f0/Mouse_embryonic_stem_cells.jpg/250px-Mouse_embryonic_stem_cells.jpg • http://cwaboulder.files.wordpress.com/2010/05/numbers.jpg • http://upload.wikimedia.org/wikipedia/commons/thumb/8/86/Africa_(orthographic_projection).svg/200px-Africa_(orthographic_projection).svg.png • http://www.psdgraphics.com/wp-content/uploads/2009/06/female-sign.jpg

  23. Thank You!

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