BOLOGY 107 Lecture 21Outline of Last Lecture I. Genetic VariationII. Variation in Cell Replicationa. Spermatogenesis b. OogenesisIII. Cell CommunicationOutline of Current Lecture IV. Mendelian Geneticsa. Polymorphism b. Genetics c. Problems with MendelCurrent LectureStart of Exam 3Mendelian Genetics1) Named for Gregor Mendel, a friar in 1865a) Studied pea plantsi) Good model system, many varieties, easy to cross- and self-pollinate, fast generation time, many offspringb) Ideas were ignored, then rediscovered in 20th century 2) Polymorphism a) Presence of multiple traits in a populationb) Character- heritable feature in a populationc) Trait- individual variants within a characteri) Example: Jaguars(1) Character- coat color, trait- black or orange3) Genetics i) Progeny tend to look like parents(1) Preformationism theory (a) “small man” in the males sperm, did not account for female(2) Blending hypothesis(a) Intermediate between both parents(i) Average of all traits, would lead to a uniform population, some children have traits not shown in parentsThese 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) Mendelial genetics(a) Genetic variation derives from different versions of a gene (alleles)(i) Diploids have two alleles, one from each parent(ii) Dominant and recessive alleles1. Recessive alleles are only seen when both the traits are recessive(b) Law of segregation(i) Two traits end up in different gametes(ii) Studied through controlled breading1. Traits are passed as units, no blending(c) Traits (i) Phenotype- observed characteristic (hair color)(ii) Genotype- genetic makeup (AAGA)(iii) Capital letters used for dominant gene, lowercase for recessive(iv) Homozygous- same trait (TT), heterozygous- different traits (Tt) (v) Parents are recorded as P, progeny as Fn, n being which generationthe subject is4) Problems with Mendela) Not all organisms have simple to map out traits like the pea plantb) Numbers he recorded are not likely to be possiblei) Confirmation bias(1) Discarded data that did not fit his
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