Search results for "Multicellular animals"

Codon usage in the siliceous sponge Geodia cydonium: highly expressed genes in the simplest multicellular animals prefer C- and G-ending codons

2001

Among a sample of 39 Geodia cydonium (Demospongiae, Porifera) genes, with an average Gh+hC content of 51.2%, extensive structural heterogeneity and considerable variations in synonymous codon usage were found. The G + C content of coding sequences and G + C content at silent codon positions (GC3S) varied from 42.4 to 59.2% and from 35.6 to 76.5%, respectively. Correspondence analysis of 39 genes revealed that putative highly expressed genes preferentially use a limited subset of codons, which were therefore defined as preferred codons in G. cydonium. A total of 22 preferred codons for 18 amino acids with synonyms in codons were identified and they all (with one exception) end with C or G. A…

Expression of one sponge Iroquois homeobox gene in primmorphs from Suberites domuncula during canal formation

2003

SUMMARY Sponges (Porifera) represent the evolutionary oldest multicellular animals. They are provided with the basic molecules involved in cell–cell and cell–matrix interactions. We report here the isolation and characterization of a complementary DNA from the sponge Suberites domuncula coding for the sponge homeobox gene, SUBDOIRX-a. The deduced polypeptide with a predicted Mr of 44,375 possesses the highly conserved Iroquois-homeodomain. We applied in situ hybridization to localize Iroquois in the sponge. The expression of this gene is highest in cells adjacent to the canals of the sponge in the medulla region. To study the expression of Iroquois during development, the in vitro primmorph…

Molecular evolution: Evidence for the monophyletic origin of multicellular animals

1995

Sponges (Porifera) as living metazoan witnesses from the Neoproterozoic: biomineralization and the concept of their evolutionary success

2010

Terra Nova, 22, 1–11, 2010 Abstract The emergence of the Metazoa can be dated back to the Neoproterozoic Era which comprises the Cryogenian Period during which two major glaciations occurred, the Sturtian and the Varanger-Marinoan. At that time, the phylum Porifera (sponges) evolved as the first animals and developed a hard skeleton. The two classes of siliceous sponges, the Hexactinellida and the Demospongiae, are already provided with the major genetic repertoire and gene regulatory networks that also exist in modern multicellular animals. Besides these metazoan innovations, the siliceous sponges display one autapomorphic character, silicatein, an enzyme which mediates bio-silica formatio…