(发育生物学）V 动物身体图式的模式建成(II).ppt

Developmental Biology
Chapter 5: Patterning the body plan in animals
- -Vertebrates
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 (体轴建立的设定)
Setting up the body axes in Drosophila
Patterning the Drosophila embryo
Establishment of the segment identity along the AP axis in adult Drosophila
2 Patterning the vertebrate body plan
Setting up the body axes in amphibians (Xenopus)
Somite formation and antero-posterior patterning (the mesodermal derivative)
Patterning the vertebrate nervous system (the ectodermal derivative)
Specifying the left-right axis (left-right asymmetry of ans)
The body axes are specified during mid-oogenesis through the reciprocal signaling between the oocyte and the surrounding follicle cells
The sequential expression of different sets of zygotic genes patterns the body plan along the AP axis
Segment polarity genes
Homeotic selector genes
All vertebrates, despite their many outward differences, have a similar basic body plan
The skeleton of a mouse embryo illustrates the vertebrate body plan
The AP axis: head, trunk with paired appendages (vertebral column脊柱) and the post-anal tail
The vertebral column is divided into cervical (neck), thoracic (chest), lumbar (lower back), and sacral (hip and lower) regions
The DV axis: the mouth defining the ventral side and the spinal cord the dorsal side
Left-right symmetry: while the vertebrate body is outwardly symmetric with respect to the left and right sides, single ans such as the heart and liver are arranged asymmetrically with respect to the dorsal midline
Patterning the body plan in vertebrates
Early development in Drosophila is largely under the control of maternal factors that sequentially activate a different sets of the embryo’s own genes (zygotic genes) to pattern the body plan.
Vertebrate axes do not form from localized determinants, as in