BOLOGY 107 Lecture 21 Outline of Last Lecture I Genetic Variation II Variation in Cell Replication a Spermatogenesis b Oogenesis III Cell Communication Outline of Current Lecture IV Mendelian Genetics a Polymorphism b Genetics c Problems with Mendel Current Lecture Start of Exam 3 Mendelian Genetics 1 Named for Gregor Mendel a friar in 1865 a Studied pea plants i Good model system many varieties easy to cross and self pollinate fast generation time many offspring b Ideas were ignored then rediscovered in 20th century 2 Polymorphism a Presence of multiple traits in a population b Character heritable feature in a population c Trait individual variants within a character i Example Jaguars 1 Character coat color trait black or orange 3 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 parents 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 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 alleles 1 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 breading 1 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 generation the subject is 4 Problems with Mendel a Not all organisms have simple to map out traits like the pea plant b Numbers he recorded are not likely to be possible i Confirmation bias 1 Discarded data that did not fit his hypothesis
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