strapping on crash helmet...
I also think the runner alien comes with the queen facehugger, combining two embryos in one facehugger, the runner being there to protect the queen until she can start a hive. But what if the runnner looks and acts the way it does because it is designed as the queen's prtector and not a regular drone. Could it be made smaller, more agile, quicker, stealthier, and not have some of the features seen on drones in other movies to help it complete it's mission?
Nothing directly from the films is conclusive evidence of DNA assimilation (minus the cloning from A:R, and I still don't know why alien DNA would infiltrate the host) but I know DNA assimilation is described in numerous other sources and is almost universally excepted.
Crash helmet on...fire away lol