V动物身体图式的模式建成I.ppt

Developmental Biology
Patterning the body plan in animals
--invertebrates
Pattern formation is one of the essential principles of development (I)
Morphogenesis is the developmental process of forming the tissue, organ and embryo. For example, embryogenesis is the process by which the embryo with a well-ordered spatial arrangements of differentiated tissues ans is formed.
Morphogenesis involves bination of cell proliferation, differentiation, movement, adhesion and induction. However, the question of how this morphogenesis happens is really about pattern formation(模式建成).
Pattern formation is the process of developing a programme or blueprint for constructing the embryos. It initially involves laying down the overall body plan (身体图式) -defining the main body axes of the embryo so that the head (anterior) and tail (posterior) ends, and the back (dorsal) and underside (ventral) are specified.
The main body axes are the antero-posterior axis, which runs from the head to the tail, and the dorso-ventral axis, running from the back to the belly. These two axes are at right angles to each other.
While the body axes are specified, the embryo is patterned along both the antero-posterior, and dorso-ventral axes. So, pattern formation is prised of the body axes specification/formation, and patterning along the body axes.
Different species specify the body axes at different times, using different mechanisms.
Pattern formation is one of the essential principles of development (II)
Patterning the body plan in animals
1 Development of the Drosophila body plan
Specification of the antero-posterior and dorso-ventral axis in Drosophila oocyte
Setting up the body axes in Drosophila
Patterning the Drosophila embryo
2 Patterning the vertebrate body plan
Setting up the body axes in amphibians (Xenopus)
Somite formation and antero-posterior patterning
Patterning the vertebrate nervous system
Patterning of the Drosophila embryo along the body axes
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