Categories of Type I retrocopy events. A. Examples of Type Ia exon acquisitions contributed by "same orientation" of retrocopies (in magenta or dark red) with respect to host gene (light blue); not drawn to scale, splice events are marked by angled lines, open reading frames are depicted as vertically striped thick bars, UTRs by medium size bars, introns in the host gene as light blue lines (for symbols and colors, see also keys below). When parts of retrocopies are described they correspond to what they used to be in the parent gene. The retrocopy's start and stop codons are shown by green and red vertical bars, respectively. Retrogene parts apparently not recruited as functional modules are overlayered with gray. B, Examples of Type Ib exon acquisitions contributed by "reverse orientation" retrocopies. For detailed descriptions, see text.