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http://flymove.uni-muenster.de/Processes/Segmentation/SegmentGes.html. wg. WT. Mirror image duplication. A>. P. A>. P. A>. P. loss of P. <A. A>. A>. <A. WT. en. anterior. posterior. WT. en. http://flymove.uni-muenster.de/Processes/Segmentation/SegmentGes.html.
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http://flymove.uni-muenster.de/Processes/Segmentation/SegmentGes.htmlhttp://flymove.uni-muenster.de/Processes/Segmentation/SegmentGes.html
wg WT
Mirror image duplication A> P A> P A> P loss of P <A A> A> <A
WT en
anterior posterior WT en
http://flymove.uni-muenster.de/Processes/Segmentation/SegmentGes.htmlhttp://flymove.uni-muenster.de/Processes/Segmentation/SegmentGes.html
CHRISTIANE NUSSLEIN-VOLHARD Max Planck Institute Tuebingen, Germany
Saturation mutagenesis: -identify mutations in all possible genes involved in embryo patterning -saturation reached at ~5 mutations per gene
Saturation mutagenesis: -identify mutations in all possible genes involved in embryo patterning -saturation reached at ~5 mutations per gene tossing marbles into bins How many bins are there?
Saturation mutagenesis: -identify mutations in all possible genes involved in embryo patterning -saturation reached at ~5 mutations per gene 15 marbles tossed into bins 5 5 5 Probability of missing fourth bin in 15 trys:
Saturation mutagenesis: -identify mutations in all possible genes involved in embryo patterning -saturation reached at ~5 mutations per gene 15 marbles tossed into bins 5 5 5 Probability of missing fourth bin in 15 trys: 0.75 15 = 0.013
Saturation mutagenesis: -identify mutations in all possible genes involved in embryo patterning -saturation reached at ~5 mutations per gene ~99% probability there are only 3 bins 15 marbles tossed into bins 5 5 5 Probability of missing fourth bin in 15 trys: 0.75 15 = 0.013
dorsal ventral posterior anterior Genes that control pattern and polarity in the embryo: Maternal genes: 1. anterior-posterior -bicoid -nanos 2. terminal -torso 3. dorsal ventral early Zygotic genes: 1. Gap genes 2. Pair-rule genes 3. Segment polarity genes 4. Homeotic genes late
bicoid, nanos double: -only torso bicoid, torso double: -only nanos nanos, torso double: -only bicoid Triple mutant: -no information
Maternal genes: Bicoid Hunchback Segment polarity genes: Engrailed Wingless Decapentaplegic Hedgehog Gap genes: Hunchback Kruppel Knirps Giant Homeotic genes: Ubx abdA abdB Antp Pair-rule genes: Even-skipped Ftz Runt Prd Odd-skipped
Knirps phenotype expression
Kruppel Mirror image duplication phenotype expression
Maternal genes: Bicoid Hunchback Segment polarity genes: Engrailed Wingless Decapentaplegic Hedgehog Gap genes: Hunchback Kruppel Knirps Giant Homeotic genes: Ubx abdA abdB Antp Pair-rule genes: Even-skipped Ftz Runt Prd Odd-skipped
Pair rule: Even-skipped phenotype expression
HairyRunt EveFtz
wg WT
Maternal genes: Bicoid Hunchback Segment polarity genes: Engrailed Wingless Decapentaplegic Hedgehog Gap genes: Hunchback Kruppel Knirps Giant Homeotic genes: Ubx abdA abdB Antp Pair-rule genes: Even-skipped Ftz Runt Prd Odd-skipped
WT en
wg WT
http://www.ucalgary.ca/UofC/eduweb/virtualembryo/D_m_segment_I.htmlhttp://www.ucalgary.ca/UofC/eduweb/virtualembryo/D_m_segment_I.html
giant Gap genes kruppel knirps Pair-rule stripes Even-skipped
bicoid hunchback knirps
Knirps phenotype expression
BICOID bindings sites in the Hunchback and Knirps enhancers Hunchback Knirps Ma et al. (1996) Development 122 (4): 1195. The EMBO Journal (1998) 17, 5998–6009
Cell. 2007 Jul 13;130(1):153-64. Cell. 2007 Jul 13;130(1):141-52.
Is cooperativity sufficient? Spatial Bistability Generates hunchback Expression Sharpness in the Drosophila Embryo Francisco J. P. Lopes1,2,3*, Fernando M. C. Vieira3,4, David M. Holloway5,6,7, Paulo M. Bisch3, Alexander V. Spirov1,2 PLOS Computational Biology (2008) 4:e1000184
BCD Cooperative binding n=~5 Hb + Positive feedback loop