Analysis of eukaryotic proteomes has shown that all but a small proportion of the eukaryotic protein repertoire is formed from protein domains which have been extant since the origin of eukaryotes [ 67].
Because of the anatomy of B. schlosseri, coupled with its hematopoietic-related gene repertoire, we hypothesize that colonial ascidians may have retained and elaborated many components of the ancestral hematopoietic program, much of which has been lost in extant solitary urochordates and cephalochordates.
We speculate that the free-living proto-apicomplexan ancestor possessed within its mitochondrion a regulatory process mediated by RNA-binding activities of the RAP proteins, which has been retained by the extant apicomplexans and chromerids.
As both the Archosaurs and Squamates evolved from early reptiles approximately 285 MYA [ 63], and as modern-day relatives of both groups share the transient structure, it is plausible that it represents an ancient character trait which has been conserved in certain extant species.
It houses Hungary's oldest extant printing press, which has been operating since 1561.
The oldest extant production is the one Fokine mounted for the Royal Danish Ballet in 1925 and which has been maintained in Denmark since then.
The other extant work is the duke's own tomb, which once stood in the chapel at Champmol but which has been reassembled in the Museum of Fine Arts in Dijon.
It is possible that extinct alligators and gharials had salt glands, which have been lost in the extant species.
The unicellular choanoflagellate Monosiga brevicollis, which have been regarded as the closest extant relative of the last unicellular ancestor of metazoans [ 20], also have well conserved ciliary genes.
Given the relationship of Kiwi with the extinct Moa and the extant ratites, which have been noted for their large eyes [31], it seems safe to conclude that reduced reliance upon visual information is a derived characteristic in Kiwi and is probably an example of adaptive regressive evolution [32].
