Hachi's posts

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The order of each primordium’s emergence (and thus its location) determines the expression of specific organ identity genes → development into a particular floral organ

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Organ identity genes encode transcription factors that regulate the development of floral organs

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Meristem identity genes encode transcription factors that regulate the genes involved in conversion from indeterminate vegetative meristem to determinate floral meristem

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Production of a flower by a shoot apical meristem stops the growth of that shoot

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Flower formation = phase change from vegetative growth (indeterminate) to reproductive growth (determinate)

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New leaves that develop on juvenile axillary buds will also be juvenile, regardless of the phase of the shoot apical meristem

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Juvenile nodes/internodes retain juvenile status even after the shoot apical meristem has changed to adult phase, vice versa

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In animals, developmental stages affect the whole organism, but transitions in plant developmental stages (phases) occur only in shoot apical meristem

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Activation or inactivation of developmental genes results from cell-cell communication (signals from neighbors)

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Cell differentiation depends on the control of gene expression, producing specific proteins

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Animal cell fate is largely lineage-based - Hox genes encode transcription factors that determine proper number/placement of structures

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Position-based - cell fate is established late, determined by final location and signals from neighbors

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Lineage-based - cell fate is determined early, cells pass this identity on to their progeny. Pattern is mapped according to direction of stem cell division/expansion

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Morphogenesis → development of specific structures in specific locations (pattern formation)