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Australia: The Land Where Time Began |
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Dictyostelium
Development – Novel Pattern of Evolutionary Conservation According to von Baer’s law the most conserved
stages of the development of an animal are the early stages. A modified
“hourglass” pattern in which an early, though somewhat later stage, is
most conserved, has been given support by more recent evidence. The
relative complexity of either temporal or spatial interactions have
explained both patterns; the time of the most complex interactions is
when the highest level of conservation and the lowest level of
evolvability occur, as larger effects are caused by these that are more
difficult for selection to alter. Tian, Strassmann & Queller1
suggest it may be the case that this general kind of explanation might
apply universally across independent multicellular systems, which is
supported by recent findings of the hourglass pattern in pants. In the
study reported here RNA-seq expression data obtained from the
development of the slime mould
Dictyostelium was used to
show that it doesn’t follow either of the 2 canonical patters, rather
there is a tendency for it to show the strongest conservation and the
weakest evolvability late in the development. Tian, Strassmann & Queller1
propose that this is consistent with a version of the spatial
constraints model which has been modified for organisms that never
achieve a high degree of developmental modularity. Tian, X., J. E. Strassmann and D. C. Queller
(2013). "Dictyostelium Development Shows a Novel Pattern of Evolutionary
Conservation." Molecular Biology and Evolution 30(4):
977-984.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |