Now my new theory, and the one that i believe most is that the markers are some alien forces method of controlling life upon a planet.
Basically it would have two functions, And that hte two intertwining halves of the markers each produce one of these functions.
function one would be to protect life upon planets from necromorphs to ensure that the life develops normally. The DNA markings are part of the system that it would use to repel, suppress, and potentially destroy these creatures. The red marker would be flawed in that it embodies this function primarily.
the second function is the extermination of life via creation of necromorphs. The convergence event is the restart button, whiping out life and starting the process over from the beginning. This function would be enabled if life proved itself a threat to the marker builders (how about we just call them "the builders" guys, its alot easier). The titan marker would be the embodiment of this function.
the shards of the red marker had this function triggered by what it perceived as an attack upon it at the end of dead space.
Well that's my new theory guys
Hope you like it more than my last theory