This web page was produced as an assignment for Genetics 564, an undergraduate course at UW-Madison .
What is a microarray?_____________________________________________________________________
A DNA microarray is also known as a DNA chip, and is used to compare gene expression between two biological states. As an example, a microarray can be used to compare gene expression in a cancer cell to that in normal cells. One chip contains thousands of spots. Fixed to each spot are many strands of a specific single-stranded nucleotide sequence, usually representing one gene. In order to perform a microarray analysis, mRNA is extracted from cells or a tissue of interest. The mRNA would then hybridize to the single-stranded probes on the chips. The color of the spot represents one biological state, while the intensity tells how highly one gene is expressed in one biological state as compared the other. |
DRD2 microarray data_________________________________________________________________________________________
The GEO Profiles database was used to obtain microarray profiles for DRD2 gene expression based on studies by different groups.
Using 'DRD2' alone as the search input yielded many results, none of which were related to impulsive behavior. Using 'DRD2' and 'impulsivity', on the other hand, did not yield and search results. Therefore, the terms 'DRD2' and 'addiction' were used to obtain the following data:
Using 'DRD2' alone as the search input yielded many results, none of which were related to impulsive behavior. Using 'DRD2' and 'impulsivity', on the other hand, did not yield and search results. Therefore, the terms 'DRD2' and 'addiction' were used to obtain the following data:
Organism: Rat
This profile clearly shows that DRD2 is highly expressed in the nucleus accumbens of the brain in rats, compared to other regions in the rat brain. The data is obtained from studies of the effect of cocaine addiction on reward-related brain regions.
This profile clearly shows that DRD2 is highly expressed in the nucleus accumbens of the brain in rats, compared to other regions in the rat brain. The data is obtained from studies of the effect of cocaine addiction on reward-related brain regions.
Organism: Human
In this profile based on a study of cocaine abuse on the midbrain, the results do not seem to show high highly significant differences in DRD2 expression between the cocaine group and the control group.
In this profile based on a study of cocaine abuse on the midbrain, the results do not seem to show high highly significant differences in DRD2 expression between the cocaine group and the control group.
Discussion__________________________________________________________________________________________________
The lack of significant differences in DRD2 expression between the cocaine group and the control group in the GDS5047 profile may mean a number of different things:
The lack of significant differences in DRD2 expression between the cocaine group and the control group in the GDS5047 profile may mean a number of different things:
- DRD2 is not directly involved in addictive behavior
- DRD2 signalling is very complex, involving many regulatory factors and subtle interactions
- The studies from which the data was extracted may possibly have involved DRD2 with different polymorphisms or even different DRD2 isoforms