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Unit 3.4 Studying Human Genetics and Biotechnology

Unit 3.4 Studying Human Genetics and Biotechnology. Page 67. Entry 44 Honors 4/23. Describe the difference between an GENEtic Disorder and a Chromosomal Disorder. Describe the difference between an Autosomal Chromosomal Disorder and a Sex Chromosomal Disorder. .

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Unit 3.4 Studying Human Genetics and Biotechnology

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  1. Unit 3.4 Studying Human Genetics and Biotechnology Page 67

  2. Entry 44 Honors 4/23 • Describe the difference between an GENEtic Disorder and a Chromosomal Disorder. • Describe the difference between an Autosomal Chromosomal Disorder and a Sex Chromosomal Disorder.

  3. Entry 40 11/2 Draw the PICTURE Pedigree • A chart of an individual's ancestors used in human genetics to analyze inheritance of certain traits Twins Study http://player.discoveryeducation.com/index.cfm?guidAssetId=B8EBDD99-B341-44E3-9834-F7C198E0786C

  4. A. Problems Studying Human Genetics 1. Ethically irresponsible to conduct testcrosses on humans. • Testcross: method to determine the genotype for a dominant phenotype (AA or Aa?), always use homozygous recessive to compare unknown to. 2. Humans have long life spans and it requires decades to produce several generations to study. • Small number of offspring (and long gestational periods)

  5. Techniques Used to Study Human Genetics 1. Population Sampling- determine how often a trait appears in a small randomly selected group, then apply to the entire population. 2. Pedigrees: graphical record of the inheritance of a single trait over several generations. • Determined based on family/historical documents, interviews, photographs, and medical records.

  6. C. Pedigrees • Shapes represent individuals in pedigrees, connecting lines represent relationships. • Helpful Hints for figuring out pedigrees • If the pedigree is showing a SEX-LINKED trait: • No male carriers • Trait cannot be passed from father to son • More males will express the trait

  7. If the pedigree is showing an AUTOSOMAL recessive trait • Trait can skip a generation • Trait CAN be passed from father to son

  8. Pedigree Activity • Reminders: • You may ask ONE question about directions; you can ask as many as you want about content • We are using BEADS instead of PomPoms • You are to remain at your lab station DO NOT WANDER or you will sit in your seat. • There are 12 beads total I better receive 12 beads upon completion or there will be a point deduction. • The beads should never leave the table (ie. Throwing, rolling, tossing etc)

  9. Ticket out the door How many males possess the trait? 2. How many females possess the trait? 3.What is the genotype of the second male in generation III?

  10. D. Human Genome Project • The Human Genome Project: is a collaborative effort among scientists worldwide to map the genes of humans. Allowing them to detect gene variations on the chromosomes which may indicate a disorder. • Hopes are to develop gene therapy or genetically based medicines. • http://app.discoveryeducation.com/player/view/assetGuid/EF68C74E-129F-4FF1-82D1-EA428498E9AC

  11. E. Detection of Genetic Disorders • Genetic Counseling: can help parents determine the chances of passing a harmful genetic trait to their child • Sonograms: use of sound waves to produce a picture of a fetus • Used to evaluate baby’s growth and development

  12. Detection of Genetic Disorders • Blood tests: used to screen for proteins • Alpha-Feto protein test (AFP)- Levels determine if baby is at risk for Down’s syndrome, Turner’s , or spina bifida.

  13. Amniocentesis: Removes amniotic fluid with fetal cells which can be cultured and produce a karyotype. • Karyotype: a picture of the chromosomes • Can identify Down’s, Klinefelters, and Turners. • Chorionic Villi Sampling: removes tissue from the placenta for karyotyping. • This can be done earlier in pregnancy and is more risky.

  14. Karyotypes (not in the notes)

  15. F. Prevention/Treatment • Genetic diseases cannot be cured but treated: • Pain medication: to relieve symptoms. • Occupational Therapy: help people who have conditions improve their ability to perform everyday tasks • Blood Transfusions: Sickle-cell/ Hemophiliacs may require this. • Gene Therapy: use vectors (viruses) to replace defective genes with normal ones • Ex. Treating cystic fibrosis and hemophilia

  16. Ticket out the Door Pedigree • Identify the following disorder • in the Karyotype. • Klinefleter’s Syndrome • Sickle Cell • Nondisjuction • Hemophilia

  17. Entry 43 4/20 • Draw a pedigree and decided if this is an example of Autosomal or X-linked and if it is dominant or recessive. Include genotypes Chad and Veronica got married and had Brittany, Kirsten, and Harry. It was discovered that Chad was a carrier and Harry had muscular dystrophy. Brittany married Larry and had Stephan and Stephanie. Stephan also had muscular dystrophy. Larry’s brother Barry also had muscular dystrophy but neither of their parents had the disorder.

  18. G. DNA Fingerprint • DNA fingerprint- A unique band pattern made of DNA fragments. • Unique to every individual, unless you have an identical twin • Uses for DNA Fingerprinting: • Violent Crimes – determines source of DNA left at a crime scene. • Paternity - used to determine the father of a child

  19. Gel Electrophoresis- tool used to create a DNA fingerprint, it separates pieces of DNA based on size (# of base pairs). Steps in DNA Fingerprinting • Step 1: Restriction enzyme cleaves the DNA sample at a specific sequence. • Restriction enzyme: the enzymes that “cuts” the DNA between the nitrogen bases • Cleave: to Cut (between nitrogen bases)

  20. Step 2: DNA fragments are loaded into wells on a gel. • Step 3: Bands are created as electricity forces DNA fragments through the gel. Small pieces move further than larger pieces. • Step 4: Compare to other DNA samples.

  21. H. Genetic Engineering • Genetic Engineering: Modifying DNA or creating recombinant DNA. • Transgenic Organism: an organism which contains foreign DNA from another species. • Recombinant DNA: form of artificial DNA that is created by combining two different sources of DNA.

  22. Process in creating Transgenic organism: • Step 1: Restriction enzyme is used to cleave the desired gene from a DNA sequence (ex. Insulin). • Step 2: The same restriction enzyme is used to cleave the vector. • Vector: The structure used to carry the foreign DNA, bacterial plasmids are commonly used. • Plasmid: Circular DNA found in bacteria

  23. Step 3: Foreign DNA and Vector spliced together • Splice: Combine • Step 4: The recombinant DNA is inserted into the host (bacteria cell). Then the host cell will copy and produce the protein. • Insulin can be produced in large quantities by using genetic engineering and bacteria.

  24. I. Bioethical Concerns for Genetic Engineering • Should we produce artificial proteins? • Allergic reactions (adding a peanut gene to a corn plant) • Stem cell research • Environmental problems from creating transgenic organisms: • Super weeds • Antibiotic resistant bacteria • Destruction of beneficial insects like bees by pesticides

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