| Budget Amount *help |
¥5,590,000 (Direct Cost: ¥4,300,000、Indirect Cost: ¥1,290,000)
Fiscal Year 2014: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2013: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2012: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Outline of Final Research Achievements |
Echinoderms are a curious group of deuterostomes that forms a clade with hemichordates but has a pentameral body plan. In contrast to hemichordateswith an organized Hox cluster, a sea urchin has a Hox cluster with an atypical organization. We report a comprehensive examination of hox expression in a sand dollar. Nine hox genes are expressed in the adult rudiment, which are classified into two groups: one with linear expression in coeloms and another with radial expression around the adult mouth. The linear genes may endow the mesentery with axial information to direct postmetamorphic transformation of the digestive tract, whereas the radial genes developmentally correlate with the morphological novelties of echinoderms and/or sea urchins. Recruitment of the radial genes appears to be accompanied by the loss of axial roles. This in toto co-option of the hox genes provides insight into the molecular mechanisms underlying the evolution of echinoderms from a bilateral ancestor.
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