【科学60秒】致病基因有益？
Gene for Disease Has Healthy Flip Side
Sickle cell disease is a blood disorder due to a single genetic ____1____ . It remains in populations because the mutation has a ____2____ —it helps to protect against malaria. Now another mutation has been shown to afford similar protection. Deficiency in the enzyme glucose-6-phosphate-dehydrogenase, known as G6PD deficiency, leads to ____3____ and jaundice. The condition affects more than 400 million people.
Scientists had thought that the ____4____ of the deficiency might also be linked to protection against malaria, but they weren’t able to find a connection in Africa. Now a study in Asia shows how the gene for G6PD-deficiency can indeed help. It appeared in the December 11th edition of the journal Science. The deficiency is particularly common in Myanmar and Thailand. So researchers spent eight years studying the Karen people in Thailand, who live near the Myanmar border. They showed that the mutation definitely reduces the number of malaria-causing Plasmodium vivax ____5____ , lessening the severity of the disease.
This protective effect has kept the genetic condition active in the population. Researchers hope that the good side of the mutation can be exploited to develop new and better ways to fight malaria.
—Cynthia Graber
