According to the theory of chemical evolution (Oparin-Haldane), the sequence of origin of life is:

1. Synthesis of organic monomers: Formation of diverse organic molecules (like amino acids, sugars) from inorganic constituents .
2. Synthesis of organic polymers: Formation of giant molecules like RNA, Protein, and Polysaccharides .
3. Formation of protobionts: Aggregation of these giant molecules into non-cellular forms (capsules) that could reproduce their molecules .
4. Formation of DNA-based genetic systems: Evolution of the first cellular forms of life with membranous envelopes and stable genetic material (DNA evolved from RNA) .