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. 2014 Jul 17;42(14):9131–9145. doi: 10.1093/nar/gku590

Figure 6.

Figure 6.

Evolutionary path for amplicons genesis in GLC1DM/HSR cell lines. Green lightning indicates breakage events; red dashed semicircles and curved arrows represent sequence deletions and duplications, respectively. Orange cross lines indicate homologous recombination (HR) events. Pink semicircle lines indicate the creation of new fusion junctions, labeled by appropriate SV codes. If undetermined, they are defined by a question mark. (A) The ancestral single-chromosome episomes, excised from their original location at chromosomes 1, 8 and 21, are amplified in the form of hsr(2), DM2/hsr(16) and DM3, respectively. The subsequent non-HR between chromosomes 1 and 8 episomes originated the shared hsr(8) amplicon structure, being associated with the duplication of sequences flanking the breakpoint regions on both ancestral episomes. The newly originated amplicon underwent three independent rearrangement types, indicated in (B) as enclosed in a gray dashed rectangle. Pink and pale blue squares (C, D) encompass the evolutionary paths observed in GLC1DM and GLC1HSR, respectively. (C) A single deletion event (SV A14) (B, left) generated the amplicon found at DM4. A further internal rearrangement (B, center) or alternatively its recombination with the chromosome 21 amplicon (B, right) originated the DM1 and DM5 amplicons, respectively. (D) The excision of a sub-region of 1q24.1 from the ancestral hsr(8) amplicon generated the amplified segment at hsr(3). A recombination-deletion event involving the hsr(8) and DM3 amplicons, followed by an inversion (B1) and HR, gave rise to the amplicon at hsr(8)b and hsr(1) in GLC1HSR. Finally, the subsequent excision of a sub-region encompassing 21q22.12 and 1q24 originated the hsr(4) amplicon.