GENETICS LAB MIDTERM ILECTURE I1.) MALE VS. FEMALE DROSOPHILA- The two best ways to distinguish sex is to look at external genitalia and sex combs- Do not look at coloring because very young flies will have very little pigmento Males have sex-combs on their forelegso Females may have an ovipositor and have a cone shaped, smooth genitaliao Male have dark, bumpy genitalia2.) PICKING ARTICLESAll articles must be 2010 or more recent3.) PLAGIARISMYou may not copy someone else’s words, ideas or structure of their argument4.) POPULAR VS. SCHOLARLY RESOURCESPopular source material is written for the general public by staff or freelance writers.- Popular sources are available to buy in stores- Have lots of color pictures and ads- Ex: websites, newspapers and magazinesScholarly information are primary sources (research papers) and secondary sources (review articles)- Can be found and downloaded from popular websites but the ultimate criteria is if it’s PEER REVIEWED (UT Library and Ulrichsweb can help determine that)- Ex. PubMed, Science, EBSCO, Lexis-Nexis, Google Scholar5.) RESEARCH PAPERS VS. REVIEW PAPERSReview articles are written by scientists who have read, evaluated and summarized many research papers published in a certain field of study- Review articles represent a bigger picture than a single research paperResearch papers describe original research findings and are written by scientists who completed the work presented. Undergo a rigorous peer-review process before publication.Steps of peer review:1. Paper is read by experts in the field2. Experts make comments on the scientific validity of the author’s claims3. The author revises the paper to determine whether it is worthy of publication6.) DROSOPHILA CHROMOSOMES - There are 8 drosophila chromosomes- They are diploid- There are four pairs of drosophila7.) ANNOTATION OF CHROMOSOMES/ separates alleles; separates chromosomesMaternal/PaternalEx:+/+; +/+; +/+; +/+8.) LIFE-CYCLE OF SORDARIATerminology- Mycelium: Filamentous growth- Perithecium: Bag full of asci- Ascus: product of one zygote that has undergone meiosis and mitosis- There are eight ascopores9.) WHY SORDARIA IS USED- Haploid parents combine to form diploid zygotes- Different strains can be easily combined- Zygotes undergo meiosis to produce haploid spores- Haploid spores always express their genotype since there are no other copies to mask the allele- Meiotic products are clearly organized in simple linear arrangement of spores10.) MUTATIONSApterous No wings apYellow Yellow body yVestigial Brown Brown eyes and short wrinkled wingsvgbwSepia Ebony Dark body and eyes seCinnabar Bright red eyes cnBar Small, slit eyes BScarlet Bright red eyes stEbony Dark body eCurled Curled wings CuScalloped Wings are rough around the edgessdPink Eye color darker and moreuniformpBrown Brown eyes bwWhite White eyes wLECTURE II1.) SCIENCE WRITING- Good writing tells a story- There is a sequence of events and there is a reflection- Thesis statement: a single declarative sentence that states what you want your readers to know, believe or understand after having read your essay. o Clear and ambiguouso Precise and limitedo Controversial or informativeo DefensibleGood science writing:- Has a point- Says something new- Engages the reader- Specific- Has a logical flow- Precise and accurate- Written with proper grammar, spelling and punctuation- Not easy to achieve2.) STYLE REQUIREMENTS- Avoid injecting yourself and personal anecdotes- Don’t use direct quotes and paraphrase instead- Don’t use section headings- Italicize Latin based phrases- Define acronyms and then use the acronyms throughoutInternal Citations(Smith, 2004) or Smith (2004) suggested…(Smith and Jones, 2004)(Smith et al., 2004)(Smith, 2004; Smith and Jones, 2004).Basic CitationAuthor last name, First Initial, Middle initial., (rest of authors, use and for last author). Year. Article name in sentence case. Journal Title in Title Case and Italics, Volume (Journal Number), Pages. Non-standard issues- Not officially published: After journal title, replace the volume/issue with “In Press”.- Available only online or from a website: Follow APA3.) SORDARIA LAB- We cross homozygous wild type and tan strains.- Tan strain has black spores- We then observe crossing over by changes to the linear pattern4.) MI SEGREGATION- No crossing over occurs- The genetic markers separate when the homologous chromosomes separate at anaphase of meiosis I. - The + gene separates from the t gene at MI5.) MII SEGREGATION- Crossing over occurs- The genetic markers do not separate until the sister chromatids divide at meiosis II- The + gene does not segregate from the t gene until MII6.) RECOMBINATION FREQUENCYIt is necessary to divide the % MII asci by 2 to get a map unit measurement that is comparable to those figured for drosophila and other diploid organisms because each MII ascus represents four chromatids in which exchange involving only TWO chromatids of the four has occurred.Non-recombinant type:4:42:4:22:2:2:2Recombinant type:5:36:22:1:1:1:1:27.) RATES OF CROSSING OVER- Rates of crossing over allow us to determine relative distances of a single gene from either the centromere of its chromosome or another gene on the same chromosome.- When the gene and the centromere (or another gene) are close together there is a LOW RATE of crossing over.- When the gene and the centromere (or another gene) are far from each other,there is a HIGH RATE of crossing over- 1% cross over rate = 1 map unito Percentage of M2 results = cross over rate o Remember to divide by twoLECTURE III1.) WHITE EYED FLIES- Drosopterin Pathway produces BRIGHT RED pigments- Ommochrome Pathway produces BROWN pigments- Bright Red + Brown = Brick Red Wild Type- The genes white, scarlet and brown all code for related ABC* transporters- Brown and scarlet both need white to work- The cinnabar gene codes for an enzyme which produces a brown pigment- Cinnabar and brown are LINKED on chromosome 2- White is sex linked- Scarlet is on chromosome 3+/+; bw/bw; st/st; +/+  WHITE EYESwt/wt; +/+; +/+; +/+  WHITE EYES+/+; bw cn/ bw cn; +/+  WHITE EYES2.) HUMAN GENOME- There are 3 billion bp in the human genome- Only 20,000 genes are coded by the human genome- 1.5 percent of the genome are genes- Humans have 22 autosomal chromosome pairs and 1 pair of sex chromosome3.) SINES13% of the human genome consists of SINE (short interspersed elements)o SINEs are in the Interspersed Repetitive clade