Selector genes and the Cambrian radiation of Bilateria.

AUTOR(ES)

Jacobs, D K

RESUMO

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 constraint on arthropod body-plan evolution. The dispersal of selector genes in the genomes of arthropods in conjunction with the retention of a simple regulatory hierarchy in development may have caused the increased constraint seen. Increased constraint would not be expected in those organisms that are not serially constructed and presumably have not retained the simple ancestral regulatory hierarchy in development of selector gene differentiation of serial elements. The hypothesis of differential constraint tested against the fossil record in this paper can be further tested by examination of the distribution of selector genes in the genomes of arthropods.

Documentos Relacionados

• Coordinate regulation of downstream genes by extradenticle and the homeotic selector proteins.
• A test of whether rates of speciation were unusually high during the Cambrian radiation.
• The notion of the Cambrian pananimalia genome.
• Bilaterians of the Precambrian—Cambrian transition and the annelid—arthropod relationship
• A selector of transcription initiation in the protozoan parasite Toxoplasma gondii.