Chevalier de Lamarck

Different organisms originated separately by spontaneous generation from nonliving matter.

We now see a hierarchy of species because they differ in age

Species differ from one another because they have different needs.

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#Id: 9809

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hy1 and hy2 mutant are chromophore biosynthesis mutant: which fail to supress hypocotyl elongation

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Pfr is the physiologically active forms of Phytochrome

Wild type: short hypocotyl by white light

hy mutant (phytochrome mutant): long hypocotyl by white light

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A toggle model is for phytochrome interconversion

The structure of the b-hairpin region of Pr is changed to an a helix during the conversion of Pr to Pfr, which initiates other conformational changes in the protein.

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There are five phytochrome isoforms in angiosperms

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PHYA is the only gene that encodes a Type I phytochrome and predominantly perceives far-red light.

Phytochrome B predominantly perceives red light

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The PHYA gene is transcriptionally active in dark-grown seedlings, but its expression is strongly inhibited in the light in monocots.