trp operon can run even in the presence of repressor. The attenuation system permits another 10-fold control over the operon’s activity.  Thus, the combination of repression and attenuation controls the operon over a 700-fold range, from fully inactive to fully active: (70-fold [repression] X 10-fold [attenuation] = 700-fold). 

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#Id: 986

#Unit 5. Developmental Biology

In Drosophila, during the ninth division cycle-Pole cells determination

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#Id: 987

#Unit 5. Developmental Biology

In Drosophila, mid-blastula transition slowdown of nuclear division, cellularization, and concomitant increase in new RNA transcription

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#Id: 988

#Unit 5. Developmental Biology

The transition from specification to determination in Drosophila is mediated by Segmentation genes.

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#Id: 989

#Unit 5. Developmental Biology

First zygotic genes is Gap genes. Mutations in them cause gaps in the segmentation pattern.

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#Id: 990

#Unit 5. Developmental Biology

Gurken protein is a member of the EGF (epidermal growth factor) family, and Torpedo encodes a homologue of the vertebrate EGF receptor.

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#Id: 991

#Unit 5. Developmental Biology

An anterior-to-posterior gradient of Bicoid protein.