Upon publication of the original article, Barlow et al. , the authors noticed that Fig. 4b contained an inaccuracy when additional data is taken into account. We inferred a loss of GRASP in the common ancestor of cryptophytes and archaeplastids, based on the absence of identified homologues in the data from taxa that we analyzed, which include Cyanidioschyzon merolae as the single representative of red algae. However, this inference is incorrect when additional red algal taxa are considered. Using the same methods as in the original paper, we identified the following sequences in sequence data from other red algae: Chondrus crispus (XP_005713669.1), Galdieria sulphuraria (XP_005704721.1 and XP_005704722.1), Porphyra umbilicalis (OSX69770.1), and Porphyridium purpureum (evm.model.contig_2019.4 from http://cyanophora.rutgers.edu/porphyridium/). Therefore, the ancestor of Archaeplastida plus Cryptophyta likely possessed a GRASP homologue, and multiple losses likely occurred, including in cryptophytes, glaucophytes, and Cyanidioschyzon. However, because cryptophytes and glaucophytes are represented in the analysis only by one exemplar genome per lineage, loss of a GRASP gene cannot be strongly inferred (and is thus not shown in Fig. 4b). Importantly, these additional results are still consistent with the published conclusions that the last eukaryotic common ancestor possessed a GRASP homologue, and that the presence of such homologues across eukaryotic diversity does not correlate with stacked Golgi morphology.
Furthermore, while the last sentence of the second paragraph in the “Evolution of the interacting Golgi structural proteins GM130, golgin-45, GRASP55, and GRASP65” subsection of the Results section in the original manuscript reads
“However, GRASP was not identified in many cases, most prominently in Embryophyta as previously noted  and extended here to the entire clade of Archaeplastida plus Cryptophyta, as well as Rhizaria and Metamonada (Fig. 4).”,
it should in fact be
“However, GRASP was not identified in many cases, most prominently in Embryophyta as previously noted , and independently in Cryptophyta (Guillardia theta) as well as Rhizaria and Metamonada (Fig. 4).”
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Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
Department of Parasitology (BIOCEV), Faculty of Science, Charles University, Průmyslová 595, Vestec, Czech Republic
Department of Neurology, University of Miami Miller School of Medicine, Miami, USA
Department of Life Sciences, The Natural History Museum, London, UK