8Gene duplication, deletion, and transposition erode co-linearity between genomes over time, 9providing a substantial source of genomic structural variations. We developed CLfinder-OrthNet 10 pipeline to systematically trace gene duplication and transposition events by building networks based on 11 co-linearity among orthologs (OrthNets) from multiple closely related genomes. Using this pipeline, we 12 explored evolutionary events that result in erosion of co-linearity among six genomes in Brassicaceae, 13 including the model plant Arabidopsis thaliana and two extremophyte wild-relatives of Brassica crops 14 adapted to highly saline habitats. Out of 17,432 OrthNets derived from the six Brassicaceae genomes, 15 7,034 consisted of six co-linear orthologs, one from each genome, while the remaining included various 16 degrees and combinations of gene duplication, deletion, and transposition. We focused on 17 transposition-duplication (tr-d) events that lead to variations in both gene copy number and co-linearity. 32 peer-reviewed) is the author/funder. All rights reserved. No reuse allowed without permission. The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/236299 doi: bioRxiv preprint first posted online Dec. 18,