Problem:
For example,
say species A is common ancestor of B, and C. Species B is a common ancestor of D and E.
We would expect that there will be more genetic similarity between D and E than D and C. And those genetic similarity must exist in B.
In other word, we won't expect genetic similarity that don't "cross" the common ancestor or the evolutionary tree.
The exception is probably genetically engineered bacteria.
That being said, am I correct?
Some people say that we have similarity with pigs and chimps even though our common ancestors may be to far off. That won't happen right?
To summarize
I expect that evolutionary tree will form a well, tree. Genetic similarity would infect "nearby" trees and can't jump between trees without connectors, such as common ancestors.
Required:
Question: Is that what we observe for ALL species?
Any ideas? Or better yet, pointers to places where this has already been answered?