Chromosome dissection and sequencing workflow. (A) Dissociated Xenopus tropicalis froglet testes were cultured in colchicine, and 15 Chromosome 7 short arms were laser-dissected, collected and (B) amplified using Sigma WGA3/WGA4 systems. (C) Sequencing libraries were prepared by Nextera transposome-mediated simultaneous fragmentation and adaptor ligation to minimize resequencing WGA adaptors, and (D) sequenced on an Illumina GAII. (E) The resulting reads were trimmed and mapped to X. tropicalis genome assemblies v4.1 and v7.1 using Bowtie, visualized on scaffolds/chromosomes, and selected positions were validated by FISH-TSA. 1- Centromere, 2- secondary constriction.