Dividing & Deducing

3. How? Why? Dividing & Deducing Taking care of genetic information; figuring it out from a standing start Lab 8

4. Q: What is a gene?Q: What is an allele?

5. Why Mendel Matters The laws governing inheritance are for the most part unknown; no one can say why the same peculiarity in different individuals of the same species, or in different species, is sometimes inherited and sometimes not so; why the child often reverts in certain characteristics to its grandfather or grandmother or more remote ancestor; why a peculiarity is often transmitted from one sex to both sexes, or to one sex alone, more commonly but not exclusively to the like sex.” --Charles Darwin, The Origin of Species …Because Darwin sucked

6. Meiosis & Phenotype Taking care of genetic information; figuring it out from a standing start

7. Today... • We will figure out the dominant trait and genotype for a set of individuals • There will be no luck, no guessing, no random stabbing in the dark involved • We will generate and explore all possible (simple) hypotheses and rule out those that do not fit, until only one viable one remains

8. Meiosis & PhenotypeToday we’ll: • Refine problem-solving skills • Explore all strategies & outcomes to determine the best one • And save hours on homework

9. Thinking it Through • Develop lines of ‘pure breeding’ traits (green and yellow peas) • Cross them… ONLY yellow trait is evident • TWO hypotheses? • One test?

10. Thinking it Through • Two Hypotheses • Make a prediction • IF ‘this’ is true, THEN… • Model and test

11. Answer 1) the green trait had been destroyed, pushed out, eliminated 2) the green trait was silenced/hidden/overwhelmed

12. Holmes had it right When you have ruled out the impossible, that which remains, however improbable, must be the truth. --Sir Arthur Conan Doyle Basic principle of science--we work by listing hypotheses & trying to kill as many as possibleIf one survives, it’s our best description of the universe--provisionally

13. Scaling • A gene is ~1,000-100,000 basepairs* • A chromosome is tens or hundreds of thousands of genes *Includes control regions & stuff that won’t make it into the final product

14. Blinding you with Science (jargon) • Gene: A stretch of DNA that represents all the information for a product as well as when and where to make the product • Allele: A version (or flavor) of a gene; two alleles of the same gene my differ by a nucleotide or dozens of them--generally a small number • Dominant/recessive: Two alleles enter; one allele leaves (which version manifests in the organism) • NOT which version is more common!

15. The Bigger Picture • Which traits are dominant? What are individual genotypes? You can use sex to find out! • Today we’ll engage in some specific problem-solving techniques • Combinatorial thinking • Enumerating hypotheses • ‘Last one standing’ • Orderly approaches & record keeping

16. Bang it out • You don’t know, but you can “*make sex” to figure it out! * that’s about as romantic as I get

17. Blinding you with Science (symbols) • Allele: A version (or flavor) of a gene; two alleles of the same gene my differ by a nucleotide or dozens of them • Common symbolism: A vs. a or BLU vs. blu (etc.) • Homozygous: ‘same-pairing’ = has identical alleles (AA, aa) • Heterozygous: ‘different-pairing’ = has different alleles (Aa)

18. PRACTICE!! • Punnett

19. Puzzle: What’s dominant? • Imagine you are confronted with two phenotypes (foot color) • Can you tell which is dominant • What crosses should you do to quickly assign dominance & genotype? • (FYI: these are actually two different species) Blue: http://theadventuretravelcompany.files.wordpress.com/2009/02/blue-footed-booby2.jpg Red: http://farm3.static.flickr.com/2177/1621918794_be3a25433b.jpg

20. If you were trapped on the island of the boobies, could you figure out the genetics?

21. How will you know what’s dominant? • Two hypotheses? Blue is dominant vsred is dominant • First:Blue Dom – which genos => dominant appearance • Recessive phenotype • All possible blue x blue in Blue world? • All possible red x red in Blue world?

22. How will you know what’s dominant? • Two hypotheses? Blue is dominant vs Green is dominant • First:Blue Dom – which genos => dominant appearance • Recessive phenotype • All possible blue x blue in Blue world? • All possible green x green in Blue world? What crosses yield all blue? All red?

23. More Punnetts • Keep your blue work • Start ‘again’ in a RED World

24. Whatcha got? • Which models can explain all green offspring? • Anything useful? • How useful to cross to ‘same’ organisms? • ‘need’ heterozygotes • How do you get them if you don’t know?

25. A better way? • Need more room? Open x_plorer • Graded exercise – show me ‘Total Victory’ and explain what/why you won (100% or 0%)

26. MORE Vocab • Naming is hard. Your parents are their parents’ children. So what’s a parent & what’s a child? • In x_plorer: parents stay parents • Formally, you will hear P1, F1, F2 in crosses • P1: the initial parents for the events in question • F1: First filial (of pertaining to, or benefiting a son or daughter) • F2: Second filial

27. x_Plorer • An exercise to guide you in thinking • Simultaneously consider two alternative hypotheses about dominance (left half; right half) • Work through BOTH cases until you have an ordered set of tests (algorithm) to distinguish (i.e. rule one OUT) • Watch the lavender box for ‘what to do next’

28. Lab Instructor: Why ‘Total Victory’ ?

29. x_Plorer • If you cross Blue with Red and get… • Then….

31. Believing what you read “The genetics of dimples is actually rather interesting. Dimples are a dominant trait, which means that it only takes one gene to inherit dimples. If neither of your parents has dimples, you shouldn't have them either, unless you experience a spontaneous mutation. If one of your parents has dimples, you have a 25-50% chance of inheriting the gene, since it means that parent inherited the gene from one or both parents. If both of your parents have dimples, you have a 50-100% chance of inheriting the gene, depending on how they inherited their dimple genes.” http://www.wisegeek.com/what-are-dimples.htm On desktops, with chalk!

32. Phenos to Genos Deducing the latter from the former using only voyeurism

33. Phenos to GenosNOW the fun!!!!

34. MendelStar! • Given the outcome, can you predict the genotype of the parents? • Observe, Hypothesize, Predict, Model/Test • Have a plan • Write it down

35. MendelStar! • For practice purposes, use the ‘Just Mendel’ option • If NOT logged in, tutorial in main lab walks you through ‘mating and sorting’ (Show Me... menu) • If all that color & such is bugging you, use the ‘Image Simplify’ menu to focus on 1 trait • When not logged in, go to the ‘Evaluate’ destination for a list of the genotypes in play

36. Mate your own Butterflies! • Once logged in, choose ‘Find the Genotype’ • Work through problems • Have a plan • Write it down! (IF this is TRUE…) • Saves time! • After answering, hit submit; if score < 76 you’ll get a hint • You can store at any time by submitting

37. Mate your own Butterflies! • Why 76 points ‘max’? • Yep, written part in dropbox • Really, have a plan

38. Genetic Disease Presentations • -Semester Projects