منابع مشابه
The Diploblast-Bilateria Sister hypothesis: parallel revolution of a nervous systems may have been a simple step.
For many familiar with metazoan relationships and body plans, the hypothesis of a sister group relationship between Diploblasta and Bilateria1 comes as a surprise. One of the consequences of this hypothesis-the independent evolution of a nervous system in Coelenterata and Bilateria-seems highly unlikely to many. However, to a small number of scientists working on Metazoa, the parallel evolution...
متن کاملTRF2 and the evolution of the bilateria.
The development of a complex body plan requires a diversity of regulatory networks. Here we consider the concept of TATA-box-binding protein (TBP) family proteins as "system factors" that each supports a distinct set of transcriptional programs. For instance, TBP activates TATA-box-dependent core promoters, whereas TBP-related factor 2 (TRF2) activates TATA-less core promoters that are dependen...
متن کاملRetinoic acid X receptor in the diploblast, Tripedalia cystophora.
Nuclear hormone receptors comprise a characteristic family of transcription factors found in vertebrates, insects and nematodes. Here we show by cDNA and gene cloning that a Cnidarian, Tripedalia cystophora, possesses a retinoid receptor (jRXR) with remarkable homology to vertebrate retinoic acid X receptors (RXRs). Like vertebrate RXRs, jRXR binds 9-cis retinoic acid (Kd = 4 x 10(-10) M) and b...
متن کاملSelector genes and the Cambrian radiation of Bilateria.
There is a significantly greater post-Cambrian decline in frequency of ordinal origination among serially constructed Bilateria, such as arthropods, than in nonserially constructed Bilateria. Greater decline in arthropod ordinal origination is not predicted by ecologic, diversity-dependent models of decline in the production of higher taxa. Reduction in ordinal origination indicates increased c...
متن کاملBack in time: a new systematic proposal for the Bilateria.
Conventional wisdom suggests that bilateral organisms arose from ancestors that were radially, rather than bilaterally, symmetrical and, therefore, had a single body axis and no mesoderm. The two main hypotheses on how this transformation took place consider either a simple organism akin to the planula larva of extant cnidarians or the acoel Platyhelminthes (planuloid-acoeloid theory), or a rat...
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ژورنال
عنوان ژورنال: Communicative & Integrative Biology
سال: 2009
ISSN: 1942-0889
DOI: 10.4161/cib.2.5.8763