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“… And please let Mom, Dad, Rex, Ginger, Tucker, me and all the rest of the family see color” Interested in Being a Preceptor? • Reinforce your understanding of Bio182 topics • Help peers navigate 182L • Help make the course better • Learn teaching techniques while earning 3 credits Interested in Being a Preceptor? • Work with TAs to teach and develop labs • Travel to exotic locations (okay, not that) • Contact Kevin Baker ([email protected]) for more info (link on Bio182L homepage) Updates: • Last quiz average: 90% that’s ridiculous • Final draft of Project Proposals are graded, grade will be posted tonight. Graded paper will be in D2L dropbox comments • To view my comments on your in class lab assignments/homeworks… Goals for Today: • Understand properties of light and molecules • Dark side of recombination • Develop skill at deducing genotype by observation of phenotype and inheritance patterns What is “color”? And how do we ‘see’ it? Wavelengths (nm) Gamma X-rays Ultrarays violet Shorter wavelength Infrare d Visible light Microwaves Radio waves Longer wavelength nm Higher energy Lower energy Looking in at looking out http://www.bio.miami.edu/dana/pix/retina.jpg • Rods • A Cone http://www.sciencephoto.com/media/121458/enlarge Looking Deeper Where are we? The difference between 2 and 3 receptors… Or, the beautiful colors of fall Can ~10 million American males be wrong? http://www.rgblind.com/ http://www.rgblind.com/ http://www.rgblind.com/ What IS ‘color’? Wavelengths (nm) Gamma X-rays Ultrarays violet Shorter wavelength Infrare d Visible light Microwaves Radio waves Longer wavelength nm Higher energy Lower energy The brain’s interpretation of the eye’s report of (three) samplings of a narrow bit of the electromagnetic spectrum Wavelengths (nm) Gamma rays Shorter wavelength X-rays Ultraviolet Infrared Visible light Microwaves Radio waves Longer wavelength nm Higher energy Lower energy If the light is red (680 nm), which receptor do you expect to ‘hear’ it more loudly? ‘green’ receptor Think Triangulation Hypothesis A: Near & Faint Hypothesis B: Far & Loud You are allowed to make one additional auditory observation http://www.mediabistro.com/baynewser/bay_area_radio/ http://www.faqs.org/photo-dict/phrase/1715/ear.html How do you get a ‘new’ receptor? Fashioning a new gene using a hammer What’s in an Opsin? • Week 9 calendar: click on ‘Opsin’ link • Retinal eats the photon -> changes shape – Change is directly transmitted to change in opsin (which is holding retinal) • Work through the page, “see” and assemble opsin and retinal Launch ‘Opsinize’ • Starting with “green-tuned” opsin (531 nm) • Your objective: make a ‘red-tuned’ (as close to 559) nm • Your tool: mutating codon sequences • From each menu you can mutate the codon (which reflects changes in DNA) 3-Letter Code • Leu: Leucine • Ala: Alanine • Arg: Arginine • Lys: Lysine • Asn: Asparagine • Met: Methionine • Asp: Aspartic Acid • Phe: Phenylalanine • Cys: Cysteine • Pro: Proline • Gln: Glutamine • Ser: Serine • Glu: Glutamic Acid • Thr: Threonine • Gly: Glycine • Trp: Tryptophan • His: Histidine • Tyr: Tyrosine • Ile: Isoleucine • Val: Valine Thinking it through… • Shown: the only the only amino acid differences between red and green opsins • DNA sequences would be… how similar? • What happens in meiosis when th maternal and paternal chromosomes pair? • Think anything might ever go wrong? How do you get a ‘new’ receptor? • What’s the ‘easiest’ way to get a slightly different protein? – Make a new segment of DNA that happens to be similar – Start with a random stretch of existing DNA and randomly mutate until… – Copy the original gene and ‘tweek’ Remember Recombination? Things don’t always go smoothly Where to Recombine? Oooooops 2 Genes for “Green” and “Red” are 98% Similar* • • • • What does this mean? Recombination? When things go “wrong” R and G on the same chromosome (23) • “Blue” is on chromosome 7 *Howard Hughes Medical Institute “New” Genes • Green -> “Red” Opsin • Myoglobin -> Hemoglobin • Adult vs. Fetal Hemoglobin What’s seX got to do with it? • The “X” is big • The “Y” not so much • What does this mean? What’s seX got to do with it? • Autosomal: chromosome NOT X or Y • Sex chromosome: X or Y (b/c of where each joined together during meiosis) • Symbolism: normally, we don’t care what chromosome given allele is on; in sex, it matters – On the X, we designate : XA, Xa – On the Y, generally designate: Y a? • Hemizygous How come no A or What’s seX got to do with it? • • • • Consider A and a How many genotypes for females? Males? How many possible crosses? Do the cross – How can you tell it’s sex-linked? – Compare sex-linked vs autosomal It sucks to be XY • • • • R/G Colorblind Hemophilia Different anemias Duchenne Muscular Dystrophy How is this useful? Pedigrees! PTC and parentage • • • • WASH HANDS Who can taste this? Separate into haves, have-nots Each: if trait is dominant, what can you deduce about your parents? • If trait is recessive? Boys vs Girls Makin’ Babies Pair up, decide who’s the adult consenting male & who the similarly conscientious female You’re both heterozygotes (recall: ‘different-pairing’) Make the babies--hold an allele in each hand, partner picks How to determine the sex of the baby? Pediducer Deductions from Pedigrees Pediducer Rules and Conventions • What assumption about randomly selected, ‘healthy’ individual? • Justification is “Outsider” • REASON must be sufficient & necessary Pediducer Rules and Conventions • What does affected indiv. look like? • You are TESTING models – How many right for model to be right? – How many wrong... • Justification • “Check me” Two Phases • Phase I: Assign genotypes and justify • Phase II: Rule model “plausible” or “out” NO POINTS!!!!! If you don’t rule models in/out Round the Fourth Preparing for next week Reagents for glucose (One solution per test tube) • 1% glucose • 0.2% glucose • water Do it! • Appendix C--the supplies are on your benches • Do the Benedict’s test on C-1 (substituting 0.1% glucose for the 1% starch indicated) • Do the CO2 test on C-2 45 Homework If you don’t rule models in/out Pedid comp pedig solve plaus out fo three hypot