1 / 13

MISTAKES IN MEIOSIS

MISTAKES IN MEIOSIS. Beth Walker CP Biology. Nondisjunction. failure of homologous chromosomes to separate correctly during anaphase I or II of meiosis. Nondisjunction can lead to…. Makes gametes with one extra OR one less chromosome. monosomy. Monosomy  has 1 less chromosome

rupert
Download Presentation

MISTAKES IN MEIOSIS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. MISTAKES IN MEIOSIS Beth Walker CP Biology

  2. Nondisjunction • failure of homologous chromosomes to separate correctly during anaphase I or II of meiosis.

  3. Nondisjunction can lead to…. • Makes gametes with one extra OR one less chromosome

  4. monosomy • Monosomy has 1 less chromosome Ex. sperm (22) + egg (23) = baby (45)

  5. TURNERS SYNDROME

  6. trisomy • Trisomy has 1 extra chromosome Ex. sperm (23) + egg (24) = baby (47)

  7. Example of monosomy • Turner’s Syndrome  45 chromosomes *Mother only gives 22 chromosomes *Father gives 23 chromosomes

  8. EXAMPLE OF TRISOMY • Down’s Syndrome  extra chromosome #21

  9. Down syndrome karyotype

  10. Example of trisomy • Klinefelter’s Syndrome extra sex chromosome (#23)

  11. Klinefelter syndrome karyotype

  12. Polyploidy • When none of the homologous chromosomes separate the gamete stays diploid(2n) instead of separating and becoming haploid(n) • Ex. 2n gamete + n gamete = 3n baby (triploid) (abnormal) (normal) 2n gamete + 2n gamete = 4n baby (tetraploid)

  13. Polyploidy at work • Extra sets of chromosomes  polyploidy • Polyploidy is common in plants, but rare in animals (usually leads to death of the zygote in animals)

More Related