Assuming that Mew contains the DNA for all Pokemon still, Mew would also contain the DNA for Arceus. This makes Mew either the beginning or the end of the DNA chain for all Pokemon. By this I mean that either Mew was the beginning of everything and all Pokemon or following the very obvious theme of Darwinism and evolution Mew is the most evolved from the vast species of Pokemon in their universe(s). Even following the theme of Darwinism throughout the Pokemon franchise, can it be concluded that any Pokemon that are close in appearance to Mew are close in the evolutionary chain to it. So either they are the next evolution of species from Mew or they are the last step of species before Mew based on their fairy-like appearance which Mew exhibits. The list of Pokemon that we see like this are Celebi, Jirachi, Azelf, Mesprit, Uxie, Manaphy, Phione, Victini, etc. Now if we look at the base information of these Pokemon, Celebi is in charge of the forests and nature itself. This Pokemon is also a grass type concluding that Celebi is not only a legendary that governs time which is Palkia, but also nature. This would make Celebi a higher tier of legendary than Palkia, Dialga, and Giratina based on the idea that Mew is the first Pokemon and still contains DNA for all other Pokemon.

Also with this we can look at Manaphy which is considered the prince of the seas. This Pokemon doesn't have much back story other than a movie with May, but it also shares a similar body type to Mew and following evolution in the sense of Darwinism, we see that Phione which evolves into Manaphy has a more similar body type to Mew than its (franchise) evolution, where Manaphy has a more likeness to a creature better suited for sea life, but is also a water type similar to how Celebi is a grass type, and they govern the elements that they live in and still keeping close to Mew in their DNA.