UNSW Embryology
Axes- Neural Molecular Development	Embryology Home Page
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Page LinksIntroduction ReferencesAbout Notes Other pages: Early | rostro/caudal | anterior/posterior | Left/Right | Limb	Back to Molecular Development
Introduction All embryos occupy 3 D space and appear differently externally and internally within this space. This gives us 3 different axes which need to be determined: Head/Tail (rostro/caudal), Front/Back (anterior/posterior), and Left/Right. The left/right axis appears at first mirror symetrical, and looks very similar externally, but clearly many internal organs are not duplicated (heart, liver, brain etc).
References Cornell RA, Ohlen TV Vnd/nkx, ind/gsh, and msh/msx: conserved regulators of dorsoventral neural patterning? Curr Opin Neurobiol 2000 Feb;10(1):63-71. Expression of vnd in ventral, ind in intermediate, and msh in dorsal columns of fly neurectoderm, and of homologous gene families in corresponding domains of vertebrate neurectoderm, suggests that elements of dorsoventral neural patterning have been evolutionarily conserved. However, upstream signaling pathways regulating this columnar gene expression pattern appear to have diverged significantly throughout evolution. In addition, while recent loss-of-function studies in flies and mice indicate that these three genes may have a conserved role in regional specification, there is no obvious conservation of the particular cell fates deriving from corresponding domains. The three-column expression pattern may thus represent a developmental mechanism that is more resistant to evolutionary changes than genetic events upstream or downstream of it. Hobert O, Westphal H Functions of LIM-homeobox genes. Trends Genet 2000 Feb;16(2):75-83 Homeobox genes play fundamental roles in development. They can be subdivided into several subfamilies, one of which is the LIM-homeobox subfamily. The primary structure of LIM-homeobox genes has been remarkably conserved through evolution. Have their functions similarly been conserved? A host of new data has been derived from mutational analysis in diverse organisms, such as nematodes, flies and vertebrates. These studies have revealed a prominent involvement of LIM-homeodomain proteins in tissue patterning and differentiation, and their function in neural patterning is evident in all organisms studied to date. Here, we summarize the recent findings on LIM-homeobox gene function, compare the function of these genes from different organisms and describe specific co-factor requirements.
Lecture Notes Please note that these notes only relate to the Anat 3311 Course. This section is not completely available, as I have been unable to transfer all my Lecture notes and research material in time for the deadline. This will be available in later versions. Early Development Lecture Simple pictures illustrating the early events of fertilization. Spinal Cord Development Figures and text relating to early events of spinal cord formation. Sex Determination Text relating to the molecular events of sex determination in the embryo. Polarity Concepts A short comparison of establishing positional information in embryos. Antennapedia The fly mutation that opened the field of Hox Genes and the conservation of pattern formation control mechanisms between species in embryonic development.
External WWW Search This current page has additional windows that allow searching of OMIM Morbid Map and OMIM Gene Map and access to other External WWW Search pages (Medical dictionaries, glossaries, chemicals and drugs). In the DNA Notes there is a window to search the Human Genome by keyword and also to search for a specific species classification. In the DNA Notes there is also a page with 3 search windows for Nucleotide Sequence, Protein Sequence and Biomolecule 3D Structure from NCBI. In the Chemical Notes there is a window to search a Material Safety Data Sheet database for a specific chemical and its associated hazard.
About Notes These lecture notes from the Embryology Program compiled and written by Dr Mark Hill. This updated section of notes is still being developed Mar2000 and is not yet complete. Note that reference lists are only relevant to the date that the original search was carried out.	Links Serial Sections Homepage Human Homepage Pig Homepage
m.hill@unsw.edu.au Date Last Modified: 19/3/99 This site maintained by Dr M. Hill