二、基因究变的概念和特 概念及其类别 1概念 point mutation Mutations: Are heritable changes in base sequences that modify the information content of DNA 2类另 Number of umber of Mutation Locus gametes tested mutations ate(X10-6) 根据基因突变的起源 a(albino 67,39 44 a自发突变 spontaneous mutation c (moag)1s b诱发突变 induced mutation2出 335045 33 332 119 根据突变后不同的表现型改变 2.220.376 12 (average a Mutation is from wildtype to the recessive allele shown a可见突变 Figure 6.3 Rates of spontaneous mutation. (a) Mutant mouse b条件致死突变 oat colors: albino(left ), brown(right).(b) Mutation rates from wildtype to recessive alleles of live coat-color genes Geneticists took C致死突交 animals from highly inbred strains with wildtype coat colors and mated therm with mice homozygous for recessive alleles of the five d生化突变 coat-color genes. The appearance of progeny with mutant coat colors indicated the presence of recessive mutations in gametes produced by the inbred mice二、基因突变的概念和特征 概念及其类别 1 概念 point mutation Mutations:Are heritable changes in base sequences that modify the information content of DNA. 2 类别 * 根据基因突变的起源 a 自发突变 spontaneous mutation b 诱发突变 induced mutation * 根据突变后不同的表现型改变 a 可见突变 b条件致死突变 c 致死突变 d 生化突变