BIOL 120 1st Edition Lecture 17Outline of Last LectureI. Overview of Meiosis II. Mitosis vs. MeiosisIII. Crossing OverIV. Results of MeiosisV. Mendel’s Experiment Outline of Current LectureI. Experiment method and Five Element modelII. Monohybrid crossingIII. Principle of Segregation IV. Punnett Squares V. Dihybrid crossingVI. Human Blood Groups VII. Environmental influence and other main ideasCurrent LectureI. Experiment method and Five Element model A. 3 stage process:1. Produce true breeding strains for the trait being studied 2. Cross fertilize true breeding strains 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.3. Allow hybrid offspring to self-fertilize for several generations and count number of off spring showing each trait B. Five Element Model1. Parents transmit genes2. Each individual receives one copy of a gene from each parent 3. Not all copies of a gene are identical a). homozygous: 2 of the same allele (RR or rr)b). Heterozygous: different alleles (Rr)4. Alleles remain discrete and do not blend  hypothesis when Mendel was conducting his experiment 5. Presence of allele does not guarantee expressions a). dominate allele always shows over recessive b). recessive only shows if both alleles are recessive genesII. Monohybrid crossingA. a process that studies only 2 variations of a single trait B. F1 generation  the offspring produced from 2 true breed strains 1. only shows dominant traits C. F2 generation  second filial generation (offspring of F1)1. result from the self fertilization of F1 plants 2. recessive traits begin to reappear in F2 3. Phenotypic ratio of  3 dominate: 1 recessive 4. Genotypic ration  1 homozygous dominant: 2 heterozygous dominant: 1 homozygous recessive D. Genes: hereditary determinants for a traitE. Alleles: different versions of a gene (usually 2)F. Genotype: allelic make up of an individualG. Phenotype: physical manifestation of genotype in an environment III. Principles of SegregationA. Idea: two alleles for a gene segregate during gamete formation and are rejoined at random (one from each parent)IV. Punnett SquaresA. a method used to determine possible genotypes B. Example of F2 generation:V. Dihybrid CrossingA. is the examination of 2 separate traits in a single crossing event B. F1 generation stills shows only dominant phenotypes C. F2 generation ratio: 9 dominant, dominant: 3 dominant, recessive: 3 recessive, dominant: 1 recessive, recessive D. Test Cross1. a cross used to determine the genotype of an individual with dominant phenotype a). you cross the individual with an unknown genotype (P_) with a homozygous recessive (pp) in order to solve the unknown E. Incomplete Dominance1. heterozygote is intermediate in phenotype between 2 homozygotes i.e. a red and a white flower produce a pink flower F. Codominance1. heterozygote shows some aspects of the phenotype of both homozygotes i.e. blood type AB (A and B are both dominant so being together makes them both appear in phenotype)VI. Human Blood groupsA. Has multiple alleles (3!)1. Type A blood  A is dominant2. Type B blood  B is dominant3. Type AB  A and B are codominant (universal receiver)4. Type O blood  has no dominant (universal donor) VII. Environmental Influence and Other main IdeasA. Environmental Influence1. temperature affects the amount of pigment alleles allow enzymes to produce B. Epistasis1. The behavior of gene production can change the ratio expected in independent assortment  not 3:1 C. Polygenic inheritance1. occurs because multiple genes are involved in controlling the phenotype of a trait  phenotype is a buildup of multiple genes 2. traits show continuous variation (known as quantitative traits) i.e. human height D. Pleiotropy1. is an allele that has more than one effect on the phenotype (cystic fibrosis)a). multiple symptoms can be tracked back to one defective