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Click to continue How do a few genes build a diversity of body parts? There’s more in the genetic toolkit than just genes! Click your forward cursor to see how it works… The Tools GENES HOX GENES REGULATORY MOLECULES (Hox Proteins) PROMOTOR REGIONS of DNA GENETIC SWITCHES
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How do a few genes build a diversity of body parts? There’s more in the genetic toolkit than just genes!. The Tools GENES HOX GENES REGULATORY MOLECULES ( Hox Proteins) PROMOTOR REGIONS of DNA GENETIC SWITCHES. Click to continue. Click your forward cursor to see how it works…. - PowerPoint PPT Presentation
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How do a few genes build a diversity of body parts?
There’s more in the genetic toolkit than just genes!
Click your forward cursor to see how it works…
The Tools
GENES
HOX GENES
REGULATORY MOLECULES (Hox Proteins)
PROMOTOR REGIONS of DNA
GENETIC SWITCHES
Gene (coding DNA)
DNA
•Turns out it takes more than just a GENE to build a body
~ 98% of DNA is non-coding Junk DNA ~ 2% of DNA contains all the GENES
•And not everything outside the coding genes is junk DNA
XPromoter
•PROMOTER REGIONS are associated with genes and help initialize transcription of the gene into a protein
Genetic
switch
Geneticswitch
GeneticswitchGenetic
switch
•GENETIC SWITCHES play a role regulating the EXPRESSION of genes
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HOX Gene
DNA
mRNAmRNAmRNA
Ribosome HOX PROTEIN
HOX PROTEIN
HOX PROTEIN
HOX PROTEIN
HOX GENES are an important set of genes in most animals. They are part of the genetic tool box that regulates development of an organism.
HOX GENES are transcribed into mRNA and then translated by the ribosomes to form HOX PROTEINS.
HOX PROTEINS then act as regulatory molecules, or TRANSCRIPTION FACTORS, that can promote or inhibit expression of other genes.
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HOX
PROTEIN
HOX PROTEIN
HOX
PROTEIN
HOXPROTEIN
Gene (coding DNA)
Promoter
Genetic
switch
DNA
RNA pol
Geneticswitch
GeneticswitchGenetic
switch
RNA pol
RNA pol
RNA pol
•RNA POLYMERASE is an enzyme in the cell•It is essential in making mRNA to translate into the amino acid sequence to form protein
•HOX PROTEINS also occur in the cell as REGULATOR MOLECULES.•When the right REGULATOR MOLECULE becomes bound to the right GENETIC SWITCH it can turn a gene ON (promote transcription) or OFF (inhibit transcription)
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Gene (coding DNA)
Promoter.
Genetic
switch
Geneticswitch
Geneticswitch
Genetic
switch
Gene (coding DNA)
Promoter.
Genetic
switch
Geneticswitch
Geneticswitch
Genetic
switch
Gene (coding DNA)
Promoter.
Genetic
switch
Geneticswitch
Geneticswitch
Genetic
switch
BUT…
•Even though every cell in the body contains the exact same DNA with the same GENES
•Not every cell contains all the same REGULATORY MOLECULES
•So only certain GENES might be turned on, or EXPRESSED, in certain types of cells
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Gene (coding DNA)
Promoter.
Genetic
switch
DNA
Regulator
RNA pol
Geneticswitch
GeneticswitchGenetic
switch
RNA pol
•In the right type of cell…•With the right REGULATORY MOLECULE•To bind to the right GENETIC SWITCH
•A GENE can be turned ON• In this case the regulator helps bring an
RNA POLYMERASE to the PROMOTOR REGION to initialize mRNA transcription
• The gene is EXPRESSED
RNA pol
Geneticswitch
Regulator
Genetic
switch Geneticswitch
Genetic
switch
RNA pol
RNA pol
RNA pol
Gene (coding DNA)
Promoter.
Genetic
switch
Geneticsw
itch
Genetic
switch
Geneticsw
itch
HOXPROTEIN
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mRNAmRNAmRNA
Gene (coding DNA)
Promoter.
Genetic
switch
DNA
RNA pol
Geneticswitch
GeneticswitchGenetic
switch
RNA pol
RNA pol
RNA polRegulator
Gene (coding DNA)
Promoter.
Geneticswitch Geneticswitch
Geneticswitch
Genetic
switchRegulator
Gene (coding DNA)
Promoter.
Geneticsw
itch
Geneticsw
itch
HOXPROTEIN
Genetic
switch
Genetic
switch
•In the right type of cell…•With the right REGULATORY MOLECULE•To bind to the right GENETIC SWITCH
•OR…
•With a different type of switch •A GENE can be turned OFF• In this case the regulator inhibits the
action of RNA POLYMERASE• The gene is NOT EXPRESSED
RNA pol
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Now on to the rest of the exercise…
You’ll have a chance to try your hand at regulating some gene expression in
arthropods!
1 set of wingsLarge and flat
Has veinsNo color
1 set of wingsLarge and flat
Has veinsHas color scales
1 set of haltiersSmall and dense
Has veinsNo color
1 set of wingsLarge and flat
Has veinsHas color scales
Now that you understand the regulatory system that controls how genes are expressed, revisit the example of wing differentiation between Drosophila and Butterflies.
Explain the genes and regulatory elements involved in the development of these wings:
T2
T3
T2
T3
Gene Switches On / Off
