New gene origin: Retrogene

https://genome.cshlp.org/content/20/10/1313

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A mature messenger RNA (mRNA) that is transcribed from a ‘‘parental’’ source gene is reverse transcribed into a complementary DNA copy, which is then inserted into the genome.

Retroposed gene copies (retrocopies) only contain the parental exon information (i.e., they usually lack pa- rental introns and core promoter sequences).

https://www.science.org/doi/10.1126/science.1178487

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In mammals, the enzymatic machinery necessary for retroposition of a gene (reverse transcriptase and endonuclease) is acquired from LINE1 retrotransposons