No one should be able to patent anything that occurs in nature. Genes that are found in the body occur in nature, and therefore should not be patentable. Just because you isolated the gene doesn't mean that you own it as your intellectual property. Imagine if someone tried to patent a plant they just found in the jungle. It would be as silly as that.
However, if the gene was synthetic then it could be patented, provided it doesn't occur freely in nature. This would mean that the government would actually have to listen to scientists, which rarely happens.