类别 全部 - genetic - mutation - migration - variation

作者:Ung Ryan 11 年以前

1187

Mutation and Genetic Drift

The text discusses mutation and genetic drift as mechanisms driving genetic variability within populations. Mutation refers to random changes in alleles, occurring at varying rates and influenced by factors such as parental age.

Mutation and Genetic Drift

Mutation and Genetic Drift

Mutation

Ultimate source of genetic variation
Good for environmental changes
95% of mutations are harmful for homozygous genes
1% of mutations are beneficial
4% of mutations are neither harmful or helpful
Age Dependent
Higher rate of mutations in older parents
Random change in an allele
1:1000-1:100000 of offsprings will have a change in allele not from the parent due to mutation

Genetic Drift

Migration
Movement of individuals between established existing populations

Population genes become more alike time goes on and migration is constantly going back and forth between the two

Bottleneck effect
Dramatic reduction in population size leading to reduced genetic variability
Founder Effect
Chance deviation of gene frequency from source population

Larger samples size the smaller the deviation from the average

Random changes in gene frequency from one generation to another
Many either fix the allele or lose it by chance

multiple alleles can't be fixed or lost