Fig. 4

Genome architecture flanking the HSA2 fusion site and the syntenic genomic regions in Great Apes and human. From the top, the figure depicts the sequences from: orangutan (PAB) and gorilla (GGO) chromosomes 2Apter and 2Bpter; chimpanzee (PTR) and bonobo (PPA) chromosomes 2Apter, 2Bpter, 9pter, 12pter and 22qter; and human HSA2, all together with the corresponding coding regions track. Each individual contig is represented by a uniquely coloured stripe consistent among species/chromosomes, labelled with the coordinates with respect to the human genome build (hg38) and designated with the arrowheads indicating the DNA strand. Dark grey contigs with white crosses depict strongly mosaic SDs or tandem repeats that cannot be graphically presented in a legible way. Brown arrowheads depict the TAR1 satellite and degenerate telomeric repeats at the HSA2 fusion site and their orthologs in Great Apes. Below each contig assembly a coloured stripe depicts: (i) green - the novel reconstructed assembly along with an approximate size, (ii) pink - the high homology region between chromosomes 2Apter and 2Bpter presumably triggering the fusion event, and (iii) light blue - the region that was lost after the fusion event with respect to the HSA2. HSA2 is also equipped with a track of collapsed SDs including ~190 kb fragment homologous to HSA9pter and three fragments ~68 kb in size in total homologous to HSA22pter. The azure contig (chr2:113,523-113,554 kb) was found to be amplified ~400 times in the chimpanzee genome [19]