(a) Ancestral GH/GHR system already emerged in the basal chordate
, and PRL/PRLR originated with the advent of Gnathostomata.
Therefore, the Ciona embryo provides an opportunity for analyzing the developmental program for the common chordate
body plan in an organism with a smaller number of genes and a compact genome.
Such a scenario would also explain why the lancelet amphioxus, a 'primitive' chordate
, has a notochord with both cartilage and muscle.
"Work from my lab has shown that enteropneusts filter feed using a pharynx perforated with gill slits, just like the invertebrate chordates
" stated Cameron.
"It clearly identifies the planet's most primitive chordate
The extinct Pikaia gracilens has been confirmed as the oldest known member of the chordate
family, which includes all modern vertebrates including humans.
Although the tumor generally arises from the valvular endocardium of the mitral or aortic valve, there have been limited numbers of reports on isolated CPF of the mitral valve chordate
. This benign tumor may present with systemic embolization.
Molecular structures and the aligned amino acid sequences of different lectins isolated from various crustaceans, chordate
, mollusca, and marine algae are quite different.
Tables in the appendix list the DNA content of chordate
cell nuclei, the RNA and DNA content of vertebrate cell nuclei, and other quantitative data.
Perhaps many genes accumulated for other sensory functions, as noted in the sea urchin, and then when the first shallow water chordate
evolved, these genes were re-wired as photoreceptors and, using the ancient eye-organizing gene, evolved into a camera-type eye.
In this context, it is assumed that prokaryotes, including their highest macroscopic complexity, the stromatolites, evolved for more than 2 billion years, eukaryotic cells appeared between 2.7 billion and 1.4 billion years ago, multicellular animals about 800 million and 700 million 0years ago and finally the Cambrian explosion of biodiversity of modern life forms including the first known chordate
about 500 million years ago.
Eukaryotic cells appear to have evolved between 2.7 and 1.4 billion years ago, multicellular animals are thought to have developed about 800-700 million years ago, and the biodiversity of modern life forms, including the first known chordate
, is known to have evolved by about 500 million years ago with the Cambrian explosion (Gould 1990; Meyerowitz 2002).
For example, the natural pigmentation of Styela embryos enabled classic studies of chordate
development (Conklin 1905; Gehring 2004).
A total of nine morphological traits including (i) leaf width in centimeters of three center trifoliolate leaves; (ii) leaf length in centimeters of three center trifoliolate leaves; (iii) leaf shape, recorded as chordate
, ovate, rhombohedric, or hastate following the classification developed by Singh et al.