Genes & Body Plans
- Created by: BioFreakinomics
- Created on: 15-04-16 14:41
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- Genes & Body Plans
- Homeobox genes
- They control the development of the body plan of an organism, including the polarity & positioning of organisms
- Are expressed in specific patterns in certain stages during development of the embryo
- How is it all controlled?
- By homeobox genes
- Maternal = effect genes = polarity
- Segmentation genes = polarity of segments
- Homeotic selector genes = identity & development of segments
- Codes for transcription factors
- Arranged in HOX clusters
- Activated from anterior to posterior
- By homeobox genes
- Retinoid acid & birth defects
- It is a derivative of Vit. A
- Activates homeobox genes
- It is a morphogen
- Too much could cause cranial deformities
- How homeobox genes work
- Some are transcription factors & bind to genes upstream & initiate transcription
- Sequence of base pairs produces polypeptides of about 60 AA
- This regulates the expression of other genes
- HOX clusters
- Copying of HOX clusters through evolution to enable organisms of higher complexity to develop from simpler ones
- The term refers to a group of clustered homeobox genes
- Drosophila = 2 HOX clusters
- Nematode = 1 HOX cluster
- Vertebrates = 4 HOX clusters
- Homeobox genes
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