Welcome back to your Mutation Station.
by Rich Feldenberg
Today we will examine the importance of the LP-mutation (Lactase Persistence-mutation), and its impact on human survival and global colonization. Creationist like to ask the tiresome question, “name a mutation that increases the information content of a gene”. I don’t think they really understand the question that they are asking, but today we will give one example of a simple mutation in human DNA that offered an advantage through natural selection to our species. There are other examples, and we’ll address some of them in later blog entries.
Lactose is a carbohydrate found in mammalian milk. It is composed of two simple sugars bonded together. Humans and other mammals evolved to be dependent on mother’s milk during infancy, but then to be weaned off milk once the animal was mature enough to begin finding food on its own. In order to digest lactose the enzyme lactase is required. Lactase is produced in the digestive tracts of the infants and young mammals, but after weaning is generally no longer produced. This is to conserve resources in the sense that it makes no sense to keep making an enzyme or other protein that is not being used.