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Genetic Disorders & Karyotypes

Genetic Disorders & Karyotypes. Review for field trip. Traits. Most of your traits or characteristics are “polygenic” - means several genes are involved Ex. skin color, hair color, height, eye color. Environment.

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Genetic Disorders & Karyotypes

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  1. Genetic Disorders & Karyotypes • Review for field trip

  2. Traits • Most of your traits or characteristics are “polygenic” - means several genes are involved • Ex. skin color, hair color, height, eye color

  3. Environment • Environmental factors CAN influence your traits (better nutrition, disease) but traits are determined by genes.

  4. Alleles • Single allele - 2 or more alternate forms of 1 gene • Ex. RR, Rr, or rr - each is an allele for flower color • Multiple alleles - 3 or more alternate forms • Ex. Blood type - A, B, AB, or O = allele possibilities

  5. Chromosomes/Genes • Homologous pairs - 1 from mom, 1 from dad • Have similar alleles on each; slightly different molecular forms • Bands = gene location for a particular allele

  6. Genetic Disorders • Occur based on problems originating on a gene • Over 200 types

  7. Genetic screening • Can be done if you have a history of genetic disorders in your family • Uses: karyotypes, blood tests for proteins, DNA testing

  8. Karyotypes • Shows unduplicated chromosomes - 1 from mom, 1 from dad • Can “easily” see problems

  9. Trisomy 21 • Has 2 chromosomes located at position #21 • Down syndrome

  10. Trisomy 18 • Rick Santorum’s child • 3 chromosomes at #18 position

  11. Marfan syndrome • Extremely long arms, legs and torso; spider like fingers • Disorder of connective tissue

  12. Angelman syndrome • Similar to autism or cerebral palsy • Lack of speech, seizures, balance disorder, need life long care • General “angel” like personality - happy, outgoing, smiling

  13. Other screening types • Amniocentesis - at 14th to 16th week of pregnancy • Common: women 35+ • Needle in belly button to withdraw amniotic fluid to examine chromosomes and proteins

  14. Other screenings • Chorionic villi sampling (CVS) - takes cells from developing fetus (zygote) at 8-10th weeks.

  15. Table 12-1 pg. 246 • Some common genetic disorders • Will be doing a project on a disorder soon

  16. Treatment • Genetic counselor - works with parents to determine probability of genetic disorder in their offspring • Pedigree = family tree

  17. Treatment • Can sometimes alter diet if an enzyme is missing • Cystic fibrosis - pounding on back to loosen mucuous; ventilator • Hemophilia - drugs for blood clotting • Surgery in utero

  18. Gene therapy • Placing healthy copy of gene into cells of person who has defective gene. • Have to know sequence of genes (bases) that are defective.

  19. Gene therapy • 1. Healthy gene inserted into the DNA of a virus • 2. Virus inserted into lungs of patient • 3. Virus infects cells • 4. Healthy gene is now in cells; can make proteins that were missing • Is temporary - have to repeat

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