BIOL 111 1st Edition Lecture 13 Outline of Last Lecture I. ReviewII. OVERVIEW OF CALVIN CYCLEIII. Melvin CALVIN CycleIV. Photorespiration: an evolutionary relic that causes problemsV. Adaptations Around This RelicOutline of Current Lecture I. Before Mendel (<1860s)—ideas about inheritanceII. Gregor Mendel (1822-1884): the Revolutionary monkIII. Experiment #1IV. Experiment #2V. MeiosisVI. How to geneticists represent alleles?VII. Law of segregation VIII. Experiment #3: Test CrossCurrent Lecture- Before Mendel (<1860s)—ideas about inheritanceo- Gregor Mendel (1822-1884): the Revolutionary monko Training in mathematicso Simple system-Pea plants: True breeding plants- Very prolific (get lots of offspring), grow very quickly, have lots of characteristics that are easy to follow- If you let the plant self-fertilize, the characteristics of the plant stay true Study one characteristic at a time- Mendel didn’t try to study everything at once and used different experimentsto study different characteristics Use quantitative analysis, determine patterns- Counting, measuring to get data- Experiment #1o Monohybrid cross: two true-breeding plants What traits appear in F1?- Purple and white flowers, the dominant trait is purple and the recessive is white Review:- P-the parents- F1-the offspring- True-breed- Hybrid- one of each of the traits from the true-breeding parents- Dominant-the trait that appears - Recessive –the trait that is covered up by the dominant traito Mendel’s simple system True breeding pea plants Study one characteristic at a time Count and determine patterns- Experiment #2 o What traits appear in F2?o Repeat with different characteristicso Notice ratio~3:1—Why? Realized that the blending hypothesis did not work anymore and decided to make a different modelo What is an allele (or heritable factor)? Like sister chromatids except that alleles are different from one another because one is from mom and one is from dad while sister chromatids are exactly identical to each other o Review F2-second generation of species Allele-heritable factors that can be passed down form generation to generation - Meiosis oo Where are alleles during gamete formation? An individual trait has only one allele in gamete formation - How to geneticists represent alleles?o Dominant trait-CAPITAL lettero Recessive trait-lower case lettero Use letters to show all possible alleles present in gameteso Punnent square: used to predict possible offspring allele combos from parents with known genetic makeup - Law of segregation o Following one trait o Allele pairs separate (segregate) suring gametogenesis and re-pair at fertilizationo Review: Homozygous-same alleles (AA, aa) Heterozygous-different alleles (Aa) Phenotype-the outward appearance of an individual (flower color purple) Genotype-the actual genetic make up of the individual (the alleles, AA)o F2 ratios:- Experiment #3: Test Crosso Determine unknown genotype of a dominant phenotype by crossing with recessive homozygote—why? If you did not cross with the homozygote, you would not know whether the unknown was homozygous or heterozygouso- Experiment #4: Dihybrid cross follow two traits for two generationso Now following two traits, start out with true breeding individuals and wants to find out if two traits are inherited independently/dependentlyo How to alleles segregate? Independently or dependently?o Copy and past picture 14-8 from powerpoint- Law of independent assortmento Determine possible gamete alleles for P generation RRYY, rryyo Predict genotype and phenotype of F1 Dependent assortment you would get YYRR, YyRr, YyRr yyrr and would get a phenotypic ratio of 3:1 Independent assortment you would get YYRR, YYRr, YyRR, YyRr, YYRr, YYrr, YyRr, Yyrr, YyRR, YyRr, yyRR, yyRr, YyRr, Yyrr, yyRr, yyrr and the phenotypic ratio is 9:3:3:1o Following two traits at a time=dihybrid crosso Each allele pair segregates independently of other pairs of alleles during gamete
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