>>3799009Lol do you know what DNA Polymerase is? The environment of the cell is not perfect. Sometimes the wrong base pair is added to the new strand of DNA. If you have ever done gene sequencing, you will know this.
How the fuck do you think we get crazy mutant pathogen strains all the time? New Flu shot every year? Constant updating antibiotics and vaccines? Bacteria and viruses reproduce super fast, if DNA mutations never happened then we wouldn't get slightly different strains and thus new organisms.