1 / 17

Understanding Human Karyotypes & Chromosomal Disorders Journal

Learn about karyotypes, chromosome abnormalities, and syndromes like Down, Klinefelter, XYY, XXX, and Turner Syndrome. Explore genetic diagnostics and impacts on individuals.

lyleboyd
Download Presentation

Understanding Human Karyotypes & Chromosomal Disorders Journal

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. Karyotypes&Chromosomal Disorders Journal Notes

  2. Human Karyotype

  3. Karyotypes • photograph of one’s chromosomes, grouped in pairs of homologous chromosomes by size • Humans have 1 pair of sex chromosomes (XX or XY) and 22 pairs of autosomes (chromosomes that are not sex chromosomes).

  4. Chromosome Abnormalities • All abnormalities result from an error during meiosis, called “nondisjunction” non – dis – junction • The problem arises when during meiosis there is a failure of homologous chromosomes to separate.

  5. Non-disjunction of chromosomes

  6. Nondisjunction of chromosomes • If non-disjunction occurs, one gamete gets both chromosomes, the other gamete gets nothing.

  7. Analyzing Karyotypes: 1. Are there 46 chromosomes? 2. Are there 2 identical chromosomes in each pair of autosomes and 2 sex chromosomes? 3. Are there any rearrangements between chromosomes or large, obvious deletions?

  8. Individual DNA strands or genes or the DNA sequence The number of genes in a chromosome The presence of gene mutations Karyotypes DO NOT show:

  9. 6 Chromosome Disorders caused by Nondisjunction • Down syndrome (trisomy 21) • Edwards syndrome (trisomy 18) • Klinefelters syndrome (trisomy XXY) • XYY syndrome (trisomy XYY) • XXX syndrome (trisomy X) • Turners syndrome (monosomy XO) **Nearly all other nondisjunctions lead to death of embryo or child before adulthood!

  10. Chromosome Abnormalities • Down Syndrome – Extra copy of chromosome 21. Also called “Trisomy 21” • Have 47 chromosomes. • One of only a few trisomy disorders in which the child has high probability of living to adulthood • Short stature • Mental retardation • Reduced life span • Characteristic features

  11. Down Syndrome Lauren Potter from “Glee”

  12. Klinefelter Syndrome • XXY – Male • trisomy of the sex chromosomes • 47 Chromosomes • Sterile • Low testosterone • Taller than average • Often don’t know they have it unless tested.

  13. Klinefelter Syndrome XXY

  14. XYY Syndrome • Males with extra Y. • 47 chromosomes • Taller than average • Normal development – never know they have it unless tested. • May have sterility problems

  15. XXX Syndrome • Females with extra X • 47 chromosomes • Taller than average • Often develop normally – never know they have it unless tested. • May have sterility problems

  16. Turner Syndrome • XO females. • Missing 2nd sex chromosome. • This is the only monosomy in which the embryo survives. If any other chromosomes are missing then embryo/fetus does not survive. • 45 chromosomes • Sterile • Shorter than average • various other characteristic symptoms

  17. Turner Syndrome - XO

More Related