Yup, it happened.
The same folks who thought we had MILLIONS of genes were flabbergasted. Of coure we don't have millions of genes, and not all of them came from mommy and daddy (all the way back).
Some folks continue to be flabbergasted and aghast at this discovery.
some of these are called Endogenous RetroViruses (ERVs). The way that they are distributed in the human, chimp, and other ape and monkey genomes is yet another compelling piece of evidence supporting common descent.
Source: One of the 29+ evidences at Talk Origins.
OK, hang on a second, you are saying that the rhetro virus genes, that have helped us date where different breakoffs in the evolutionary tree have happened, are not genes that we get from mom and dad? or are somehow extra genes that were popped in there?
If that is what you are saying, you could not be further from the truth, and geneticists were not at all surprised to find those genetic markers, they were expected, because we know that a virus will attach their DNA signature to cells that they infect. A Virus cannot reproduce by itself, it needs help from it's host, and with that help it changes the genetic signature of that host in undeniable ways.
As I said, the genetic signatures of various virus throughout the DNA was expected, BTW, it is still the DNA you got from your parents, and the DNA they got from theirs etc, there is just a small signature from where the virus stole it's genetic material in order to reproduce.
The gene sequence numerically remains the same, but some have been switched, or changed by the virus. Most are nulls and have no effect on the progeny, and therefore are passed on generation to generation. It changes the sequence nothing more, and to say it was unexpected, well, sorry, that is an outright lie.