GEN 3022 1st Edition Lecture 2Outline of Last Lecture I. Overview of Geneticsa. Molecular Expressionb. The study of geneticsII. Overview of DNAa. Basics of DNA and RNAb. Transcription and Translationc. DNA TechnologiesIII. Gene InsertionIV. Traits a. Environmental Influence on Trait ExpressionTrait expression at different biological levelsOutline of Current Lecture I. IntroductionII. VocabularyIII. Mendel and the Pea Plant Experimentsa. Advantages of using the garden peab. Seven Characters of Inheritance in Peasc. Experimental Set-upIV. Conclusions of the ExperimentsThese 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.a. Patterns of inheritanceb. Mendel’s Law of Segregationc. Mendel’s Law of Independent Assortmentd. Recessive vs. DominantV. Punnett SquaresCurrent LectureI. Introductiona. There were many hypotheses on how inheritance works b. Many thought that inheritance involved the blending of traits from the parents tothe offspringc. Gregor Mendel used pea plant experiments to study the patterns of inheritance and came upon some ground breaking discoveriesII. Vocabularya. Hybridization: mating or crossing of two individuals with different characteristics (ex: purple flowered plant and white flowered plant)b. Hybrids: resulting offspring of the aforementioned crossc. Mendelian factors: current term is genesd. Allele: different versions of a trait on the same gene (ex: allele for blue eyes and allele for green eyes; an individual can have two of the same or one of each)e. Homozygous: an individual with two of the same alleles for a trait (two alleles forgreen eyes)f. Heterozygous: an individual with two different alleles for the same traitg. Genotype: how an individual’s traits appear genetically, not physically; looking at the alleles onlyh. Phenotype: how an individual’s traits appear physically; an individual’s outward appearancei. Character: the morpohological characteristics of an organism (ex: eye color)j. Trait: the specific properties of a character (ex: blue eyes)k. True-breeder: a homozygous individual that produces the same trait over several generationsIII. Mendel and his pea plant experimentsa. Advantages to using the garden pea: i. peas have both male and female reproductive organs, making it easy to manually cross-breed plants or self-fertilize ii. peas have many unique traits that are easy to observeb. 7 distinguishable traits that could be used to observe patterns of inheritance (height, flower color, flower position, seed color, seed shape, pod color, and pod shape)i. At first Mendel began with a single-trait cross (monohybrid cross) where he only bred for one characterii. Later he began experimenting with two-trait (dihybrid) crosses involving multiple charactersc. Experimental Set-Up: Mendel used two types of fertilization to cross plants. He then observed how the characteristics of the parent plant(s) appeared in the offspring to figure out the pattern of inheritancei. Two types of fertilization: 1. Cross-breeding: mating two different plants to each other by manually moving the pollen of one plant to the anther of another2. Self-fertilization: mating a plant to itself by pollinating its own antherii. Mendel recorded the phenotypes (and genotypes) of the parent plants and those of the offspring to observe how traits were inheritedIV. Experimental Conclusionsa. The results of Mendel’s thousands of plant crosses refuted the previous hypotheses for patterns of inheritance (blending mechanisms)b. Mendel’s Law of Segregation: each parent plant has two alleles for a given character and can be homozygous or heterozygous. During gamete formation (egg and sperm), the alleles segregate randomly so that half of the gametes receive one factor and half receive the other.c. Mendel’s Law of Independent Assortment: during gamete formation, the segregation of any pair of hereditary determinants is independent of the segregation of other pairs (similar to the Law of Segregation)d. Dominant and Recessive Traits: One type of allele is dominant and the other is recessive, meaning that if an individual is heterozygous or homozygous for the dominant allele then the individual will exhibit the dominant trait. V. Punnett Squaresa. Punnett squares are a way of predicting what genotypes will appear in the offspring for a monohybrid or dihybrid cross; this method uses the genotypes of the parents b. In a dihybrid cross with heterozygous parents (ex: TtRr X TtRr) the ratio of phenotypes of the offspring is always 9:3:3:1 (dominant-dominant: dominant-recessive: recessive-dominant: recessive-recessive)c. From a dihybrid cross of heterozygous parents, there are combinations of traits that appear in the offspring that were not seen in the