ScienceDaily: Gene That May Influence Alcoholism And Addiction Identified
Riley explained that genetic research can often be guided by additional non-genetic information. "We know that certain regions of the brain are particularly important in processing reward," he said. "Neurons which use dopamine as their neurotransmitter connect these regions, and some research suggests that there may be dopamine imbalances in these regions among alcoholics. Although these differences might be the result of chronic heavy drinking rather than its cause ... variation in genes coding for the various proteins that mediate dopamine neurotransmission might also be involved in alcoholism. The DRD2 gene, which codes for one of the five dopamine receptors, has been heavily studied for possible links to alcoholism, but with mixed results. Hence the current study."
Using data collected as part of the Collaborative Study on the Genetics of Alcoholism (COGA), a long-term project with multiple sites across the United States, researchers genotyped 26 single-nucleotide polymorphisms (SNPs) spanning DRD2 and ANKK1 in a sample of 219 Caucasian families (n=1923).
"The key finding here is that when you genotype markers not just in DRD2, the highly studied gene in this region, but also genotype markers across surrounding genes, there is evidence that surrounding genes, such as ANKK1, may also be involved in addiction phenotypes," said Dick. "If there are indeed multiple genes in the region involved, it may help explain the inconsistency surrounding whether DRD2 plays a role."
Riley concurs. "The study finds strongest evidence of association not in the DRD2 gene, but rather in the neighboring gene, ANKK1," he said. "This is notable because it suggests that the original evidence pointed to ANKK1 all along and it was the error in mapping the variant that supported the involvement of DRD2. However, the evidence in this paper is by no means conclusive that ANKK1 is involved in alcoholism, any more than the older evidence was that DRD2 was involved, and it must be interpreted with caution and further explored."
Riley explained that genetic research can often be guided by additional non-genetic information. "We know that certain regions of the brain are particularly important in processing reward," he said. "Neurons which use dopamine as their neurotransmitter connect these regions, and some research suggests that there may be dopamine imbalances in these regions among alcoholics. Although these differences might be the result of chronic heavy drinking rather than its cause ... variation in genes coding for the various proteins that mediate dopamine neurotransmission might also be involved in alcoholism. The DRD2 gene, which codes for one of the five dopamine receptors, has been heavily studied for possible links to alcoholism, but with mixed results. Hence the current study."
Using data collected as part of the Collaborative Study on the Genetics of Alcoholism (COGA), a long-term project with multiple sites across the United States, researchers genotyped 26 single-nucleotide polymorphisms (SNPs) spanning DRD2 and ANKK1 in a sample of 219 Caucasian families (n=1923).
"The key finding here is that when you genotype markers not just in DRD2, the highly studied gene in this region, but also genotype markers across surrounding genes, there is evidence that surrounding genes, such as ANKK1, may also be involved in addiction phenotypes," said Dick. "If there are indeed multiple genes in the region involved, it may help explain the inconsistency surrounding whether DRD2 plays a role."
Riley concurs. "The study finds strongest evidence of association not in the DRD2 gene, but rather in the neighboring gene, ANKK1," he said. "This is notable because it suggests that the original evidence pointed to ANKK1 all along and it was the error in mapping the variant that supported the involvement of DRD2. However, the evidence in this paper is by no means conclusive that ANKK1 is involved in alcoholism, any more than the older evidence was that DRD2 was involved, and it must be interpreted with caution and further explored."
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