BIOL 310 1st Edition Lecture 6Outline of Previous Lecture- MendelismI. Chi squaresII. What are genes and where are they located?a. Discoveries post MendelOutline of Current Lecture:I. Chromosome Types & TranslocationII. Mitosis and Meiosis are part of the cell cyclea. Chromosome structureI. Chromosome Types and Translocation- Morgan connected a specific phenotype to a specific chromosome. Specifically the X chromosome with the white fly gene. o His data was consistent with the law of segregation. - Carothers (1913)-Used chromosome translocations in grasshopper gametes, to show that non-homologous chromosomeso Discovered translocation – genes exchange onto different chromosomes during replicationo 1) __.__> >____._______ 1) _.____ __.__________2) __.__ ____._______ X 2) _.____ __.__________E1 = __.__> >____._______ E2 = __.__> ____._______ E3 = __.__ >____._______ E4 = __.__ ____._______ ** > represents a translocation **- What Mendelian expectation/hypothesis did this observation address and how?These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. _.____ __.__________o Carothers hypothesis was just another phenotype observation she just needed a microscope to see them. Her hypothesis and findings supported the independentassortment model. Blakeslee (1922)- Showed that Datura plants with an extra chromosome hadHow did these observations expand ideas about unit factors?- Showed that multiple genes were on a single chromosomes- there are 12 homologous pairs ona chromosomes. - Trisomics for different chromosomes produce different phenotypesII. MITOSIS AND MEIOSIS ARE A PART OF THE CELL CYCLEMITOSIS- equally divides the chromosomes; only in somatic cells- Cytokinesis – divides equally among daughter cells- G1 – cell contents & DNA duplicate- G0 – stays in G1 for a long time (neurons)- S – DNA & histones are synthesized - G2 – Mitosis or DIEMEIOSIS- a. Chromosome Structure:Chromosome nomenclature:G1 chromosome – end of mitosis (single strand)- Has one DNA duplex __________.________ nomenclature: |sister chromatids – during the S Phase (X) - Has 2 DNA duplex __________.____ __________.____ Nomenclature: XCentromeres cant be at the tippy top because telomeres must be thereChromosome 1 in any species is always the longest; the shortest will always be the shortestChromosomes are divided into “ARMS”p arm = short armq arm = long arm- Chromosomes are most easily observed during __M__ phase of mitosis/meiosis because - In somatic cells of diploids for each type of chromosome, there is a pair- Pairs look alike, except sex chromosomes- Human somatic cells have __46___ chromosomes 2n = 46o How many pairs? 23 n = 23 = # chromosomes in a gamete- What about Drosophila (2n = 8)? __8____ X-somes & __4___ pairs- Human zygotes received __23____ chromosomes from mother and __0__ chromosome pairso If you receive a pair of any chromosome you would be trisomic- Drosophila zygotes ___8____ chromosomes & ___4_____ pairs.- Human embryos received ___23___ chromosomes from father and ___0__ chromosome pairs - Drosophila embryos___8____ & ___4_____ pairs- A human egg or sperm contains ___23___ chromosomes and ___0__ pairs of chromosomes- Drosophila egg and sperm ____4_____ & _____0___ pairs- Chromosomes are replicated during __S____ phasePhases of chromosomes:G1 S G2 STAGES OF MITOSISINTERPHASE- cells make more DNAPROPHASE- chromosomes finalize condensation **no pairing of homologs** only happens during MEIOSIS I. METAPHASE- DNA lines up at metaphase plate ANAPHASE- DNA moving to the edges When they come apart they are daughter chromosomesTELOPHASE- DNA at the edges – divide into 2 daughter cellsLooking for # of chromosomes, right position, structureChromosomes in prophase = 4 Chromatids in prophase = 8Duplex = 8Ploidy = # of sets of things; MITOSIS PRODUCES X X X XXXX- Daughter chromosome = daughter cell- Genetically identical XeroxingMITOSIS DOES NOT- Create genetic diversity- Keeps # of chromosomes constant- No independent assortment/