@article {6360,
	title = {Knockdown of parhyale ultrabithorax recapitulates evolutionary changes in crustacean appendage morphology.},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {106},
	year = {2009},
	month = {2009 Aug 18},
	pages = {13892-6},
	abstract = {<p>Crustaceans possess remarkably diverse appendages, both between segments of a single individual as well as between species. Previous studies in a wide range of crustaceans have demonstrated a correlation between the anterior expression boundary of the homeotic (Hox) gene Ultrabithorax (Ubx) and the location and number of specialized thoracic feeding appendages, called maxillipeds. Given that Hox genes regulate regional identity in organisms as diverse as mice and flies, these observations in crustaceans led to the hypothesis that Ubx expression regulates the number of maxillipeds and that evolutionary changes in Ubx expression have generated various aspects of crustacean appendage diversity. Specifically, evolutionary changes in the expression boundary of Ubx have resulted in crustacean species with either 0, 1, 2, or 3 pairs of thoracic maxillipeds. Here we test this hypothesis by altering the expression of Ubx in Parhyale hawaiensis, a crustacean that normally possesses a single pair of maxillipeds. By reducing Ubx expression, we can generate Parhyale with additional maxillipeds in a pattern reminiscent of that seen in other crustacean species, and these morphological alterations are maintained as the animals molt and mature. These results provide critical evidence supporting the proposition that changes in Ubx expression have played a role in generating crustacean appendage diversity and lend general insights into the mechanisms of morphological evolution.</p>
},
	keywords = {Animals, Base Sequence, Biological, Biological Evolution, Cloning, Crustacea, Electron, Extremities, Gene Expression Regulation, Genes, Genetic Techniques, Homeobox, Homeodomain Proteins, In Situ Hybridization, Microscopy, Models, Molecular, Molecular Sequence Data, RNA, Scanning, Small Interfering},
	issn = {1091-6490},
	doi = {10.1073/pnas.0903105106},
	author = {Liubicich, Danielle M and Serano, Julia M and Pavlopoulos, Anastasios and Kontarakis, Zacharias and Protas, Meredith E and Kwan, Elaine and Chatterjee, Sandip and Tran, Khoa D and Averof, Michalis and Patel, Nipam H}
}
@article {955,
	title = {Global analysis of patterns of gene expression during Drosophila embryogenesis.},
	journal = {Genome Biology},
	volume = {8},
	year = {2007},
	month = {2007 July 23},
	pages = {R145},
	abstract = {<p>Cell and tissue specific gene expression is a defining feature of embryonic development in multi-cellular organisms. However, the range of gene expression patterns, the extent of the correlation of expression with function, and the classes of genes whose spatial expression are tightly regulated have been unclear due to the lack of an unbiased, genome-wide survey of gene expression patterns.</p>
},
	keywords = {Animals, Drosophila melanogaster, Embryonic Development, Gene Expression Profiling},
	issn = {1465-6914},
	doi = {10.1186/gb-2007-8-7-r145},
	author = {Tomancak, Pavel and Berman, Benjamin P and Beaton, Amy and Weiszmann, Richard and Kwan, Elaine and Hartenstein, Volker and Celniker, Susan E and Rubin, Gerald M}
}
