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11 Cards in this Set
- Front
- Back
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Homeotic Genes
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Encode for a family of structurally similar transcription factors which act to specify cell identity. Is highly evolutionarily conserved. Hox genes are homeotic genes.
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Homeosis
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Transformation of a par of one body segment into a homologous structure normally found on a different body segment.
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Homeobox
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Is cause of structural relatedness between homeotic genes. Found in all Hox genes. Encodes a 60 AA protein product called the homeodomain.
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Homeodomain
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Part of a DNA binding protein that acts as transcription regulators by controlling promoter activity. Is the DNA binding part. Encoded by Homeobox
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Spatial Colinearity
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Clusters of HOX genes are all arranged in the same order on the chromosome as they are expressed in a cranial-caudal axis. Therefore, the more 5' in a cluster a gene is, the more caudally expressed and vice versa.
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ANT-C and BX-C
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In the fruitfly, ANT-C controls differentiation of body segments of head and anterior thorax. BX-C controls differentiation of from the middle thorax to the end of the abdomen. Equivalent to our Hox genes.
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Hox genes
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Determine the segmentation of our body. Hox A-D express spatial colinearity.
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Loss of function v.s. gain of function Hox gene mutation.
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Loss of function usually leads to a cranial transformation. Gain of function usually leads to a caudal transformation.
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Paralogs
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Same Hox number but a different letter Hoxa-4, Hoxb-4 ect.
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3 sections of the adult limb skeleton from axial to distal.
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Stylopod (1 bone), zeugopod (2 bones), and autopod (lots of bones).
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What is the transcriptional control mechanism for Hox gene expression in the limb?
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A LCR-like element called the global control region (GCR) regulates HoxD 10-13.
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