Hox clusters

Many mouse homeobox genes are found in four clusters (a-d) on chromosomes 2,6,11, and 15 (Fig. 2). Each Hox cluster carries about 10 genes and displays a number of interesting features. First, genes within... 

Figure 7.5 A phylogenetic tree of animal phyla based on 18S ribosomal DNA from several laboratories (Raff, 1996). The most significant innovations are the appearance of (1) multicellularity, (2) tissues, (3) the anterior-posterior axis and central nervous system, (5) metameric segmentation, (6) pentameral symmetry, (7) neural crest and amplification of Hox clusters.

Prohaska, S. J., Fried, C., Flamm, C., Wagner, G., and Stadler, P. F. (2004) Surveying phylogenetic footprints in large gene clusters applications to Hox cluster duplications. Mol. Phyl. Evol. 31, 581-604. 

Pellerin, I., Schnabel, C., Catron, K.M., Abate, C. 1994. Hox proteins have different affinities for a consensus DNA site that correlate with the positions of their genes on the hox cluster. Mol. Cell. Biol. 14, 4532-4545. 

Santini S. and Bemardi G. (2005). Organization and base composition of tilapia Hox genes implications for the evolution of Hox clusters in fish. Gene (in press). 

Vertebrates are unique in being the only type of metazoan animals in which the ancestral Hox cluster has been duplicated due to genome duplications. In most tetrapod vertebrates, there are four Hox clusters, on different chromosomes, presumably due to 2 genome duplications. Teleost fish have 8 clusters, due to 3 genome duplications. 

Mainguy G, Koster J, Wolteiing J, Jansen H, Durston A, (2007).Extensive polycistronism and antisense transcription in the Mammalian Hox clusters. PLoS ONE 2(4) e356. 

Seo HC, Edvardsen RB, Maeland A D, Bjordal M, Jensen MF, Hansen A, Flaat M, Weissenbach J, Lehrach H, Wincker P, (2004). Hox cluster disintegration with persistent anteroposterior order of expression in Odcopleura dioica. Nature 431 67 -71. 

Wada, H., H. Escriva, S. C. Zhang, and V. Laudet. 2006. Conserved Rare Localization in Amphioxus Hox Clusters and Imphcations for Hox Code Evolution in the Vertebrate Neural Crest. Dev Dynam 235, no 6 1522-31. 

Fig.1 Genomic organization of the hox clusters in human, mouse and Drosophila. Genes are indicated by black boxes, the size in kilobases of the clusters is indicated. Note that the Drosophila complexes BX-C and ANT-C are not physically linked. The expression pattern is indicated underneath. Data is from [ 12,50,177,178]...

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