biostudies-literatureUnknown114(10)Schiemann SMTemporal collinearity is often considered the main force preserving Hox gene clusters in animal genomes. Studies that combine genomic and gene expression data are scarce, however, particularly in invertebrates like the Lophotrochozoa. As a result, the temporal collinearity hypothesis is currently built on poorly supported foundations. Here we characterize the complement, cluster, and expression of Hox genes in two brachiopod species, <i>Terebratalia transversa</i> and <i>Novocrania anomala</i><i>T. transversa</i> has a split cluster with 10 genes (<i>lab</i>, <i>pb</i>, <i>Hox3</i>, <i>Dfd</i>, <i>Scr</i>, <i>Lox5</i>, <i>Antp</i>, <i>Lox4</i>, <i>Post2</i>, and <i>Post1</i>), whereas <i>N. anomala</i> has 9 genes (apparently missing <i>Post1</i>). Our in situ hybridization, real-time quanProceedings of the National Academy of Sciences of the United States of AmericaE1913-E1922https://www.ebi.ac.uk/biostudies/studies/S-EPMC5347542biostudies-literatureClustered brachiopod Hox genes are not expressed collinearly and are associated with lophotrochozoan novelties.PMC5347542Vellutini BCHejnol ASchiemann SMBorve AMartin-Duran JMPassamaneck YJfalseClustered brachiopod Hox genes are not expressed collinearly and are associated with lophotrochozoan novelties.Temporal collinearity is often considered the main force preserving Hox gene clusters in animal genomes. Studies that combine genomic and gene expression data are scarce, however, particularly in invertebrates like the Lophotrochozoa. As a result, the temporal collinearity hypothesis is currently built on poorly supported foundations. Here we characterize the complement, cluster, and expression of Hox genes in two brachiopod species, <i>Terebratalia transversa</i> and <i>Novocrania anomala</i><i>T. transversa</i> has a split cluster with 10 genes (<i>lab</i>, <i>pb</i>, <i>Hox3</i>, <i>Dfd</i>, <i>Scr</i>, <i>Lox5</i>, <i>Antp</i>, <i>Lox4</i>, <i>Post2</i>, and <i>Post1</i>), whereas <i>N. anomala</i> has 9 genes (apparently missing <i>Post1</i>). Our in situ hybridization, real-time quan2017-01-01T00:00:00Z2017 Mar2025-04-04T11:15:14.071Z2019-03-27T02:38:29ZS-EPMC53475422822852110.1073/pnas.1614501114