Dhamma is the truthful recognition of things as they are. Form is not self. Consciousness is not self. Perception is not self. Feeling is not self. Volitional Formations are not self. Why are they not self ? Because they are impermanent. Why are they impermanent ? They are impermanent because they dependently arisen.When the dependent factors are removed the thing ceases to be.
Below I quote from SN 36.8 describe why 'feeling'(one of the five aggregates) is impermanent :
“Bhikkhus, while a bhikkhu dwells thus, mindful and clearly comprehending, diligent, ardent, and resolute, if there arises in him a pleasant feeling, he understands thus: ‘There has arisen in me a pleasant feeling. Now that is dependent, not independent. Dependent on what? Dependent on just this contact. But this contact is impermanent, conditioned, dependently arisen. So when the pleasant feeling has arisen in dependence on a contact that is impermanent, conditioned, dependently arisen, how could it be permanent?’ He dwells contemplating impermanence in contact and in pleasant feeling, he dwells contemplating vanishing, contemplating fading away, contemplating cessation, contemplating relinquishment. As he dwells thus, the underlying tendency to lust in regard to contact and in regard to pleasant feeling is abandoned by him.
Now that we understand Dhamma let us see what is dependent origination. Dependent origination is a theory which claims that All things are dependently arisen. The list of things it claims to have dependently arisen are longer. All those things are impermanent. In short ,Dependent origination shows the path impermanent phenomenon take to reach suffering. On this whole journey of dependent origination Self or I is not found at all.
Below I quote from SN 12.20SN 12.20 to support the claim that nowhere in dependent origination idea of self is found:
“When, bhikkhus, a noble disciple has clearly seen with correct wisdom as it really is this dependent origination and these dependently arisen phenomena, it is impossible that he will run back into the past, thinking: ‘Did I exist in the past? Did I not exist in the past? What was I in the past? How was I in the past? Having been what, what did I become in the past?’ Or that he will run forward into the future, thinking: ‘Will I exist in the future? Will I not exist in the future? What will I be in the future? How will I be in the future? Having been what, what will I become in the future?’ Or that he will now be inwardly confused about the present thus: ‘Do I exist? Do I not exist? What am I? How am I? This being—where has it come from, and where will it go?’
In both the cases we have reached the same conclusion that impermanent phenomenon means suffering which means they are not self. Therefore when one sees dependent origination one sees the Dhamma and vice versa.