It is sometimes claimed that evolution is not used in medicine. The discovery of genes involved in perception of pain -- Fruit flies lead scientists to new human pain gene | Bioscience Technology Online -- demonstrate otherwise.
First, genes were screened using fruit flies:
"The gene was uncovered in a genome-wide hunt for pain genes in fruit flies, which revealed hundreds of other candidate pain genes that await further study. ... took advantage of the relative ease of conducting genetic screens in fruit flies. Nearly 12,000 genes were targeted for mutations specifically in nerve cells, using RNA interference (RNAi) technology. The team then exposed the different mutant flies to noxious heat, and identified the ones that failed to fly away. After eliminating flies with other complications, such as an inability to see or fly, they zeroed in on those with mutations that appeared to be specific to pain. "
Why use fruit flies? If creationism is true, then pain in humans would bear no relationship to pain in fruit flies. Obviously fruit flies and humans are different "kinds".
"The new gene, ..., encodes part of a calcium channel called alpha 2 delta 3 (α2δ3). Calcium channels are pores in the cell membrane through which calcium ions pass, and are critical for the electrical excitability of nerve cells."
What's the next step? Testing in mice!
"Studies of mice lacking α2δ3 demonstrated that this gene controls sensitivity to noxious heat in mammals as well as flies. Further, functional MRI imaging of the mutant mice revealed that α2δ3 controls the processing of thermal pain signals in the brain: the heat pain signal seems to arrive appropriately at the thalamus, an early processing center, but does not travel to higher order pain centers in the cortex."
But why mice? Again, aren't they different "kinds"? By creationism, there is no reason they would have the same pain mechanism as humans. But by evolution, pain mechanism would arise in the common ancestor of mammals (mice and humans) and flies, i.e., the first animals. Thus the genes would be the same for fruit flies, mice, and humans.
"To determine the gene's role in human pain sensitivity, ... looked at four single nucleotide polymorphisms (SNPs), or single-letter variations in the DNA code, within or close to the α2δ3 gene in 189 healthy volunteers. They found that certain less common SNPs were associated with reduced sensitivity to acute pain in a test administering a quick series of noxious heat pulses. Additional testing in 169 patients who had undergone surgery for pain caused by herniated vertebral discs revealed that patients with these less common SNPs were substantially less likely to have persisting chronic pain."
Not only do humans have the same gene, but it serves the same function!
"Understanding the genetic basis of pain will lead to the development of new analgesics, the identification of risk factors for chronic pain and improved decision-making about the suitability of surgical treatment for different patients, "
Evolution underlies medicine.
First, genes were screened using fruit flies:
"The gene was uncovered in a genome-wide hunt for pain genes in fruit flies, which revealed hundreds of other candidate pain genes that await further study. ... took advantage of the relative ease of conducting genetic screens in fruit flies. Nearly 12,000 genes were targeted for mutations specifically in nerve cells, using RNA interference (RNAi) technology. The team then exposed the different mutant flies to noxious heat, and identified the ones that failed to fly away. After eliminating flies with other complications, such as an inability to see or fly, they zeroed in on those with mutations that appeared to be specific to pain. "
Why use fruit flies? If creationism is true, then pain in humans would bear no relationship to pain in fruit flies. Obviously fruit flies and humans are different "kinds".
"The new gene, ..., encodes part of a calcium channel called alpha 2 delta 3 (α2δ3). Calcium channels are pores in the cell membrane through which calcium ions pass, and are critical for the electrical excitability of nerve cells."
What's the next step? Testing in mice!
"Studies of mice lacking α2δ3 demonstrated that this gene controls sensitivity to noxious heat in mammals as well as flies. Further, functional MRI imaging of the mutant mice revealed that α2δ3 controls the processing of thermal pain signals in the brain: the heat pain signal seems to arrive appropriately at the thalamus, an early processing center, but does not travel to higher order pain centers in the cortex."
But why mice? Again, aren't they different "kinds"? By creationism, there is no reason they would have the same pain mechanism as humans. But by evolution, pain mechanism would arise in the common ancestor of mammals (mice and humans) and flies, i.e., the first animals. Thus the genes would be the same for fruit flies, mice, and humans.
"To determine the gene's role in human pain sensitivity, ... looked at four single nucleotide polymorphisms (SNPs), or single-letter variations in the DNA code, within or close to the α2δ3 gene in 189 healthy volunteers. They found that certain less common SNPs were associated with reduced sensitivity to acute pain in a test administering a quick series of noxious heat pulses. Additional testing in 169 patients who had undergone surgery for pain caused by herniated vertebral discs revealed that patients with these less common SNPs were substantially less likely to have persisting chronic pain."
Not only do humans have the same gene, but it serves the same function!
"Understanding the genetic basis of pain will lead to the development of new analgesics, the identification of risk factors for chronic pain and improved decision-making about the suitability of surgical treatment for different patients, "
Evolution underlies medicine.
