Examples of Hox gene in the following topics:
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- Most animals undergo sexual reproduction and have similar forms of development dictated by Hox genes.
- Hox genes do this by coding transcription factors that control the expression of numerous other genes.
- Hox genes are highly-conserved genes encoding transcription factors that determine the course of embryonic development in animals.
- In vertebrates, the genes have been duplicated into four clusters: Hox-A, Hox-B, Hox-C, and Hox-D.
- Shown here is the homology between Hox genes in mice and humans.
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- The morphological flexibility and complexity of animal development afforded by the evolution of Hox control genes may have provided the necessary opportunities for increases in possible animal morphologies at the time of the Cambrian period.
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- The B gene controls black (B_) vs. brown (bb) color, while the E gene controls yellow (ee) color.
- Genes may also oppose each other with one gene modifying the expression of another.
- Often the biochemical basis of epistasis is a gene pathway in which the expression of one gene is dependent on the function of a gene that precedes or follows it in the pathway.
- In this case, the C gene is epistatic to the A gene.
- Thus, the C gene is epistatic to the A gene.
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- Cancer, a disease of altered gene expression, is the result of gene mutations or dramatic changes in gene regulation.
- Cancer can be described as a disease of altered gene expression.
- There are many proteins that are turned on or off (gene activation or gene silencing) that dramatically alter the overall activity of the cell.
- This can be the result of gene mutation or changes in gene regulation (epigenetic, transcription, post-transcription, translation, or post-translation).
- It can bind to sites in the promoters of genes to initiate transcription.
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- Silencing genes through epigenetic mechanisms is very common in cancer cells and include modifications to histone proteins and DNA that are associated with silenced genes.
- When these modifications occur, the gene present in that chromosomal region is silenced.
- In cancer cells, silencing genes through epigenetic mechanisms is a common occurrence.
- Mechanisms can include modifications to histone proteins and DNA associated with these silencing genes.
- Describe the role played by epigenetic alterations to gene expression in the development of cancer
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- Gene duplication is the process by which a region of DNA coding for a gene is copied.
- Duplicate genes are often immune to the selective pressure under which genes normally exist.
- Many retrogenes display changes in gene regulation in comparison to their parental gene sequences, which sometimes results in novel functions.
- This can apply to genes and proteins, such as nucleotide sequences or protein sequences that are derived from two or more homologous genes.
- Both orthologous genes (resulting from a speciation event) and paralogous genes (resulting from gene duplication within a population) can be said to display divergent evolution.
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- Nucleotide variation is measured for discrete sections of the chromosomes, called genes.
- In humans, more proteins are encoded per gene than in other species.
- M.leprae has lost many once-functional genes over time due to the formation of pseudogenes.
- The repeat-rich regions contain genes coding for host interaction proteins.
- This figure represents the human genome, categorized by function of each gene product, given both as number of genes and as percentage of all genes.
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- Proteins, encoded by individual genes, orchestrate nearly every function of the cell.
- Genes are composed of DNA and are linearly arranged on chromosomes.
- Some genes encode structural and regulatory RNAs.
- Protein-encoding genes specify the sequences of amino acids, which are the building blocks of proteins .
- Both protein-encoding genes and the proteins that are their gene products are absolutely essential to life as we know it.
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- Genes exist in pairs within an organism, with one of each pair inherited from each parent.
- A gene has a certain influence on how the cell works; the same gene in many different cells determines a certain physical or biochemical feature of the whole body (e.g., eye color or reproductive functions).
- All human cells hold approximately 21,000 different genes.
- Homologous chromosomes have the same genes in the same positions, but may have different alleles (varieties) of those genes.
- Describe the structure of a gene and how offspring inherit genes from each parent
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- Prokaryotes regulate gene expression by controlling the amount of transcription, whereas eukaryotic control is much more complex.
- To understand how gene expression is regulated, we must first understand how a gene codes for a functional protein in a cell.
- Therefore, in prokaryotic cells, the control of gene expression is mostly at the transcriptional level.
- The regulation of gene expression can occur at all stages of the process .
- Eukaryotic gene expression is regulated during transcription and RNA processing, which take place in the nucleus, and during protein translation, which takes place in the cytoplasm.