BCH447H1 Chapter Notes - Chapter 4: Mutation Rate, Genetic Load, Dna Replication
Document Summary
Mutation or the creation of new alleles is the underlying cause of evolution. The minimal definition of evolution is the fixation of an allele within the population. But in the long run mutation is important. Human beings are a good model organism for understanding mutation rates. In that, how many mutations does a new born child have that are different from its parents. Ultimately all mutations come from an error in dna replication. What would be the mutation rate in humans with fundemental information. So, sperm, from zygote to maturity divide 400 times. So at the end we have 430 replication cycles before we are made. The replication machinery makes a mistakes at 1x10^-10 # of nucleotides x mistakes per run x 430 divisions. The percent of the mutations that are deleterious is extremely low. This is because 97% of the genome is noncoding. 1/3 of all mutations that occur in a protein coding gene are deleterious.
