Lecture 2-Mutations

Lecture 2-Mutations - TheNatureofNaturalSelection

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1 The Nature of Natural Selection Natural selection is not perfect: Genes may affect multiple traits Selecting for one trait may affect another in a different way
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2 The Nature of Natural Selection Selection acts on individuals NOT for the good of the species
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4 How does evolution work? Ecological processes are visible Birth Death Feeding Competition Decomposition
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5 How does evolution work? Evolutionary processes tend to be invisible We see the products of evolution, not the process
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6 How does evolution work? Evolutionary machinery = mechanism of evolution Genetics Natural selection Molecular evolution Speciation Extinction
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7 How does evolution work? Genetics is at the core of evolution Variation of genome Transmission of genetic info
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8 Gregor Mendel (1822-1884) First to describe how heredity works Pea plants
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13 Chromosome = bundle of DNA Genome = an organism’s complete set of DNA (all chromosomes)
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15 Locus/loci = locations of particular genes Gene = region of DNA (that codes for a protein)
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16 Alleles = a specific version of a gene; alternative “flavors” of a gene Fur color gene (alleles = black, grey, brown) Eye color gene (alleles = dark brown, light brown, dark blue, pale blue, green, hazel,violet)
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17 How does genetic variation arise? Chromosomes recombine during meiosis “Crossing over” Ends (“feet”) break off “Feet” recombine with other “legs” Foot/leg recombinations are random
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19 How does genetic variation arise? Law of independent assortment Different gametes can be produced from the same sets of chromosomes Genes on non-homologous chromosomes assort independently of each other
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20 How does genetic variation arise? Fertilization occurs randomly: Many sperm are available, only one gets to pair with each egg Which sperm wins is random
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21 Natural Selection Natural selection exploits genetic variance to increase fitness It is an editor, not a writer Mutation is a writer, creating new forms
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23 How does genetic variation arise? Mutations
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24 How does genetic variation arise? Mutations: Point mutations One nucleotide is replaced (e.g. adenine replaces a thymine) Base pair substitutions Creates new alleles
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How does genetic variation arise? Mutations
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This note was uploaded on 08/30/2008 for the course BIOS 230 taught by Professor Gibbons during the Spring '08 term at Ill. Chicago.

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Lecture 2-Mutations - TheNatureofNaturalSelection

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