SM Research Institute

Welcome to the St. Mark’s Institute of Research:

We are happy to have you as part of the new cohort of biological researchers this year. Our lab prefers to immerse you immediately into research as opposed to a slow orientation process. Therefore, this letter introduces you to your first Research Project. You should also note that the individuals with whom you are stationed will be your first Research Team of the year.

Our research facility has been interested in recent human evolution and how our evolution may be a consequence of culture and environment. Specifically, we have been examining the phenomenon of lactose tolerance in humans.

The inability of humans to digest lactose was first described by researchers at the University of Manchester in England in the journal The Lancet on May 30, 1959. The team studied two siblings, a brother and a sister, both of whom were diagnosed with “failure to thrive in infancy” and had chronic flatulence, diarrhea, and abdominal pain. They determined that neither could digest the sugar lactose, but both could absorb glucose and galactose when consumed together. They provided two hypotheses to explain their observation: 1) neither child was producing the lactase enzyme, or 2) the lactase enzyme was being inhibited by another substance the children were producing. The team further postulated that because both children had the trait, it was likely hereditary, and because the parents of the two children could digest lactose, the trait did not follow a dominant inheritance pattern.

This single report quickly led to other studies, and by the mid-1960s scientists were reporting variations in the distribution of lactose intolerance among people from different ethnic backgrounds. In 1970, Frederick Simons, a professor of geography at the University of California at Davis, proposed that the addition of goat and sheep milk to human diets starting 10,000- 6,000 years ago could explain the geographic distribution of lactose intolerance. By the mid-1970s, it had become clear to Western scientists and medical doctors that lactose intolerance was the more prevalent condition and the ability to digest lactose, or lactose tolerance was more rare.

Our lab is continuing research on the phenomenon of lactose tolerance. Our lab is interested in the question of “Why are some people lactose tolerant and others are not?” To study this phenomenon we have collected the following data and need help in the completion of further testing and analysis.

- - Subject Samples: Intestinal fluid samples of subjects from various geographic regions
  - Family Inheritance Data: Pedigrees from from 4 Finnish families
  - Lactase Persistence Demographics: Age, Sex, and Geographic Location

Your Research Team is charged with reviewing and analyzing this data and providing a summative Evidence-Based Explanation to the lab’s Research Question - “Why are some people lactose tolerant and others are not?”

As this is your first Research Project, your Research Director will provide you with more direction and support than you will be given in future projects. That being said, this Research Project should give you a good sense of your course experience. Enjoy!

Sincerely,

Research Directors: Kimberley Berndt and Caleb Corliss