11 BIOL 1001 Mutation Natural Selection (Jan. 30) post-lecture

Eg humans highest muta3on rate 1 muta3on10 000 gametes

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Unformatted text preview: recombina/on! Does sexual recombina3on change allele frequencies in a popula3on? 99 Sources of gene3c varia3on • How do we get new alleles? • Muta0on – ul3mate source of varia3on How are muta0ons passed on? How do new combina0ons of alleles arise? • Arise from random processes 100 The Nature of Muta3on • Muta0on – ul3mate source of varia3on • Good/bad/no effect à༎ depends on environment organism is in • Random wrt needs of the organism •  As evolu3onary mechanism, muta3on is rela3vely slow compared with selec3on, gene3c driQ and gene flow. •  E.g., humans – highest muta3on rate = 1 muta3on/10 000 gametes •  If 2 gametes unite à༎ at most 1/5000 offspring muta3on at par3cular gene •  Would take a long 3me for that 1 allele to get to frequency of 1% •  Larger impact on organisms that are haploid or have short genera3on 3mes •  But can restore gene3c diversity that is eliminated through the other mechanisms of evolu3on. •  Without it, evolu3on would eventually stop… 101 Evolu3on •  Occurs when the allele frequencies in a popula3on change •  (microevolu3on) •  Processes (mechanisms) in microevolu3on •  Muta3on •  Natural selec0on •  Gene3c driQ •  Gene flow (migra3on) •  Non- random ma3ng 106 Natural Selec3on •  Describe the mechanism of evolu3on by natural selec3on, explaining why evolu3on is not progressive (i.e., moving towards ‘perfec3on’), how natural selec3on is non- random and results in adapta3ons. [Comprehension] •  Describe how natural selec3on acts on phenotypic varia3on to alter the gene3c structure of a popula3on. [Comprehension] •  Differen3ate between the various types of selec3on (e.g., direc3onal) and their effects (e.g., gene3c varia3on, mean character value) on a popula3on (either alone or in tandem) over a period of 3me. Given a scenario, determine the type(s...
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This note was uploaded on 03/03/2013 for the course BIOL 1001 taught by Professor Dr.kelly during the Spring '13 term at York University.

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