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

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

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

Meiosis & Phenotype Today we’ll: Refine problem-solving skills Explore all strategies & outcomes to determine the best one – And save hours on homework

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

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

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 possible If one survives, it’s our best description of the universe-- provisionally

13 Scaling A gene is ~1, ,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

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)

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: booby2.jpg Red:

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

How will you know what’s dominant? Two hypotheses? Blue is dominant vs red 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?

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?

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

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?

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

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

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’

Lab Instructor: Why ‘Total Victory’ ?

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 % chance of inheriting the gene, depending on how they inherited their dimple genes.”genetics trait, which On desktops, with chalk!

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

Phenos to Genos NOW the fun!!!!

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

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

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

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

Genetic Disease Presentations -Semester Projects