9 29 Lecture Summary Mutations 2 Causes of mutations Homeotic Mutations Regulates clusters of genes controlling development Ionizing rradiation Chemical mutagens Spontaneous mutations during DNA replication Some mutations can be repaired with drugs Mutation rates 1 gamete in 10 carries a mutant Effects of mutation Harmful Lethal minor or major most mutations are recessive No Effect neutral mutation mutation for equivalent code on OR mutation does not effect fitness blue or brown eyes Beneficial Increases fitness of an organism 1 Mutations determine survival and reproductions 2 Most mutations have negative fitness 3 Mutations are random not directed by environment Today s view of mutations role Sexual and genetic recombination provide variability by shuffling existing alleles Mutations provide variability for new alleles LAMARCK Evolution by acquired characteristics use disuse DARWIN nat selection Weismann Nat selection Humans DNA s way of more DNA Kramer Frog guy People had trouble replicating his effects Committed suicide after being accused of being a phony Epigenetics Changes in the expressions of a gene that occur w o changing the DNA sequence Adding methyl groups Histone modification of chromatin more loose or more tight Histone balls of protein that DNA are wrapped around
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