1. Chemical Mutagens: These are substances that can alter the DNA sequence, leading to mutations. Some examples include:

* Ethyl methanesulfonate (EMS): A widely used chemical mutagen that causes point mutations.

* Sodium azide: Another commonly used mutagen that induces primarily point mutations.

* Nitrous acid: Causes deamination of bases, leading to substitutions.

2. Radiation: Exposure to ionizing radiation, such as X-rays or gamma rays, can damage DNA and cause mutations. This method is less commonly used than chemical mutagens, as it can be more difficult to control and may have unintended consequences.

* X-rays: Cause DNA strand breaks and base modifications.

* Gamma rays: Similar to X-rays but penetrate deeper into the organism.

It's important to note that while these methods can increase the rate of mutation, they don't guarantee the creation of specific desirable traits. The mutations introduced are often random and can lead to harmful effects as well as beneficial ones.