Anesthetizing Flies – Using CO2Too little causes flies to fly offToo much causes them to be infertile or dieJust right allows us to examine themDetermine females from malesDo not go by color! Because the coloring might be due to a mutation.Sex combs are present on males. Dark genitalia on male. Cone shaped genitalia for female.Next week:Purpose is to deduce a pattern of inheritance. Working with model organismsCompiling and Analyzing dataMaking null hypothesisTesting validity of nullConducting chi squareMaking white eyed flies, there are three crosses possible. F2 generation is data set working with to determine what kind of mechanism was involved. Drosophila labSet parental generation crossesSordaria LabInoculate culture platesLAB attendance is mandatory!!Next WeekHomework #2Writing Assignment Topic SelectionWriting Assignment #1 Topic SelectionSubmit your topic during lab meeting for approvalArticle should not be older than 2010How to distinguish between scholarly paper and research papersPopular vs. scholarly resourcesAppendix 38 chromosomes, diploid, 4 pairs of drosophilaWildtype  + allele+/+  wildtype homozygous representing chromosome 1+/+; +/+: +/+; +/+/ separates alleles; separates chromosomesChromosome 1 represents the sex chromosomeX/Y Dominant AlleleCu/+Recessive Allelee/eMaternal/PaternalExample:Write the different gametes this genotype will produce?+/+; +/p: +/e; +/++;+;+;+ +;+;e;++;p;+;++;p;e;++/e +/ee/e+/++/+;+/+ x p/p;e/eF1 +/p;+/eWEEK 2Fly lab #2, part 2Page 22Delete P generationSordaria part 2 analysis (p. 61-62)WA#1 Topic Selection!Bring to lab!Science WritingGood writing tells a storySequence of eventsReflectionRead appendix 3THESISA thesis statement is a single declarative sentence that states what you want your readers to know, believe, or understand after having read your essay. A statement of the point the essay makes.You should be thinking about what you want the whole essay to say. What you want the reader to know or believe at the end of the essay, not the beginningThe thesis statement should beClear and ambiguousPrecise and limitedControversial and informativeDefensibleCareful attention to format!! Every journal has different requirements for format andstyle. The authors are expected to meet those requirementsSORDARIAHaploid/DiploidHaploid parents combine to form diploid zygotesDifferent strains can be easily combinedThe mature offspring is haploidZygote undergoes meiosis to produce haploid sporesMating ResultsParathecis form at midline due to mating between the strains (wt and tan)MII Pattern: 2 light, 2 dark, 2 light, 2 darkMI Pattern, 4 light, 4 darkYou can view the asci by taking a perithecium from a culture and placing it in a drop of water on a slide. If you gently press on a coverslip covering the drop, the parathecium will burst open and release the asciCount for 25, look for MI and MII patterns2:4:22:2:2:2Unusual ascopore patterns are due to gene conversionGene conversion: homologous repair mechanism, homologous chromosome as template on altering gene sequence on the other chromosome. RATES OF CROSSING OVERRates of crossing over allow us to determine the relative distances of a single gene From the centromere of its chromosome:If it is very close to centromere, low rates of cross overIf it is very far from centromere, high rates of crossing overFrom another gene on the same chromosomeClose genes  low cross over ratesFar genes  high rate of cross overMAP UNITSRates of crossing over allow us to determine relative distances of a single gene from the centromere of a chromosome or the distance between two genes on the same chromosome. 1% cross over rate = 1 map unitMost useful in organisms without mapped genomesCalculation in SordariaPrecentage of recombinants1% cross over rate = 1 map unitcrossover rate should equal percentage of m2 resultsHALF OF THE %M2Only half show crossing over!This also makes it equivalent to other systems where gametes are scored individually instead of in sets WEEK 3You must observe/score offspring carefully in order to correctly deduce how mutated eye color is transmittedIt takes either white by itself or it takes a combo of bw and st or bw and cn to make whiteTo be linked, on the same chromosomeEye color in drosophila depends on a number of genesDrosopterin pathway produces bright red pigmentsOmmochrome pathway produces brown pigmentsBright red + brown = brick red wild typeWhite eyes can be the result of a single mutation or combo of two different mutationsThe genes w, bw, st all code for related ABC transporters. Used to deliver pigment precursors to converting enzymes. Brown and scarlet both need white to workThe cinnabar genes codes for an enzyme which produces a brown pigmentCinnabar and brown are on the same chromosomeScarlet is on 3HUMAN GENOME22 pairs of autosomal chromosomes and 1 pair of sex chromosomesIn terms of base pairs, what is the size of the human genome3 billion bpHow many genes does the human genome code for?20,000What is a gene?Unit of inheritanceA gene is segment of a genome that encodes a single specific end product or a functional unit of information. 1.5 percent of the genome are genesWhat accounts for the rest?Coding and regulatoryIntronsRepeatsNon coding RNAsTransposonsPseudogenesFocus on SINE13% of genesSINES are transposable elements that are capable of moving to different locations within a given genomeThey are highly repetitive that do not code for any genesWhen inserted between genes, introns, they are genetically neutralAlu PolymorphismAlu inserting into exons may be implicated in some diseases and disordersBenefits: they can provide alternate splicing in genes which leads to genetic diversityCan provide info on human evolution and dispersalAlu is DIMORPHICTwo possible PCR products641 bp (no insertion) PRIMER--------------PRIMER941 bp (insertion) PRIMER------300BPALUINSERT----PRIMEREach student will isolate their own genomeAmplify PV92 region of chromosome 16Electrophoresis of amplified samplesThe frequency of the alleles is not the same as the frequency of the genotypeGenomic frequency is NOT the same as the allelic frequency. Allelic frequency is a separate characteristic of a population.Magnesium ion is needed by DNAseCritical stepsInstaGene, 56 degrees Celsius and 100 degrees CelsiusWhat is required for PCR?PrimerTemplateNucleotidesMg ionsBufferHeat stable DNA polymerase (Toq polymerase)Don’t put chelator in PCR, because chelator binds magnesiumNegative control