The 60-species multiple alignment and conservation track released in 2012 for the GRCm38/mm10 mouse assembly was the largest comparative alignment track generated by UCSC to date. In 2013, we undertook an ambitious project to produce a 100-species conservation track on the GRCh37/hg19 human assembly, released to the public in Nov. 2013. As part of this undertaking we have been evaluating software alternatives, such as Cactus (20), to extend the scalability of our multiple alignment pipeline, which has been challenged by the increasing number of species.
