碩士 / 國立臺灣大學 / 漁業科學研究所 / 85 / The polymerase chain reaction was carried out in order to
survey the homeobox-gene fragments of sea urchin, Tripneustes
gratilla, and starfish Archaster typicus. A total eight
sequences were identified. The results of comparative analysis
with known homeobox sequences suggested that six sequences were
of the Hox type. One of the six sequences may be the anterior-
type group gene, four may be the medial-type ones, and two may
be the posterior-type ones. These results suggested that
echinoderms may have a single cluster of Hox-Complex. Possibly,
only one anterior-type group gene exists in echinoderms, which
is different from the hemichordates and the cephalochordates
that are close relatives of echinoderms. This difference is
probably due to the lack of cephalic structures in the
echinodermae body form. Echinoderms have at least two posterior-
type homeobox genes, implying that the tandem duplication of the
ancestral gene of this group occurred in echinoderms as other
deuterostomes. Besides, two sequences were of the Xlox family of
the sea urchin and the starfish. In addition, the expression of
the Xlox family homeobox gene in the starfish embryos was
detected by reverse transcription polymerase chain reactions.
The expression of mRNA of the Xlox family gene in the starfish
embryos was detected during two periods from egg to cleavage and
from gastrula to early bipinnaria. A maternal effect role in the
early development and a role in the enteroceol formation or the
differentiation of the gut cells in the later period are
proposed for the Xlox family gene.
| Identifer | oai:union.ndltd.org:TW/085NTU00451010 |
| Date | January 1997 |
| Creators | WU, JEN-YI, 吳貞儀 |
| Contributors | CHANG-PO CHEN, 陳章波 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 70 |
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