Sarah Rodrigues
Bio 345
June 22, 2019
Lactose Tolerance and Human Evolution
In the HHMI movie by Dr. Sarah A. Tishkoff, she explains how lactase persistence is an example of human adaption. Throughout her lecture she goes into detail about how lactose tolerance and lactose intolerance came to be, and how this adaption developed. In this paper I am going to address five specific questions that explain the adaption of lactose tolerance/intolerance in adult humans. The proximate mechanism that provides lactose tolerance in adult human is the activation of the lactase enzyme in our bodies. As children our bodies produced this active enzyme lactase (found in the small intestine), which allows for the breakdown of the sugar lactose that is present in milk. As adults this enzyme is shut off, but due to a genetic mutation in some people they “maintain the expression of this gene at …show more content…
All mammals including humans are born with the active form of the enzyme lactase. As babies we can digest the sugar lactose in milk because the active enzyme can breakdown the sugar lactose and it can be digested without any problems. Where the problem arises is as you get older and become an adult this enzyme shuts off and people become lactose intolerant. The people who can tolerate milk have been found to have a genetic mutation near the gene that produces lactase enzyme started becoming more frequent. If you have this genetic mutation than you will be able to digest the sugar lactose as an adult. However, according to Dr. Tishkoff, “there is some evidence that as people get much, much older there can be a slight decrease in the prevalence of the gene expression activity, but it will not be not huge for that particular trait” (Lecture 2). This development of lactose tolerant is recent trait that has only risen in the past few thousand years, which in evolution this is a very short time period for something to
Bio 345
June 22, 2019
Lactose Tolerance and Human Evolution
In the HHMI movie by Dr. Sarah A. Tishkoff, she explains how lactase persistence is an example of human adaption. Throughout her lecture she goes into detail about how lactose tolerance and lactose intolerance came to be, and how this adaption developed. In this paper I am going to address five specific questions that explain the adaption of lactose tolerance/intolerance in adult humans. The proximate mechanism that provides lactose tolerance in adult human is the activation of the lactase enzyme in our bodies. As children our bodies produced this active enzyme lactase (found in the small intestine), which allows for the breakdown of the sugar lactose that is present in milk. As adults this enzyme is shut off, but due to a genetic mutation in some people they “maintain the expression of this gene at …show more content…
All mammals including humans are born with the active form of the enzyme lactase. As babies we can digest the sugar lactose in milk because the active enzyme can breakdown the sugar lactose and it can be digested without any problems. Where the problem arises is as you get older and become an adult this enzyme shuts off and people become lactose intolerant. The people who can tolerate milk have been found to have a genetic mutation near the gene that produces lactase enzyme started becoming more frequent. If you have this genetic mutation than you will be able to digest the sugar lactose as an adult. However, according to Dr. Tishkoff, “there is some evidence that as people get much, much older there can be a slight decrease in the prevalence of the gene expression activity, but it will not be not huge for that particular trait” (Lecture 2). This development of lactose tolerant is recent trait that has only risen in the past few thousand years, which in evolution this is a very short time period for something to