Kaessmann, "Evolutionary fate of retroposed
gene copies in the human genome," Proceedings of the National Academy of Sciences of the United States of America, vol.
Although most retroposition events result in non-functional duplicates (called pseudogenes), in rare cases, retroposed
genes, like Rps23r1, can become functional.
Kim, "Rapid Evolution of a Recently Retroposed
Transcription Factor YY2 in Mammalian Genomes," Genomics 87 (2006): 348-55; J.
Elements as Archives for the Evolutionary History of Placental Mammals.
Another type of genetic analysis involves the use of retroposed
genetic elements (retroposons; reviewed in Deininger and Batzer 1993).