This project is important for understanding the extent to which human life history can be interpreted from microscopic features in the skeleton, providing insights relevant to many basic science initiatives concerned with mineralized tissue biology, anthropology, and bone aging. The initiatives associated with this project will likely be a model for establishing faculty and student research partnerships among American universities and the University of Malawi.
The skeleton is unique in preserving in its mineralized framework the signatures of an individual's life history. For instance, how fast one grows and for how long, and body size are life history characteristics that may be evaluated from microscopic features in one's bones and teeth. Employing a skeletal sample of sub-Saharan Africans of Bantu origin and known life history, the researchers are testing novel hypotheses regarding relationships between both bone and tooth microanatomical characteristics and human body size and compare the findings with people of Anglo-Celtic origin. A microanatomical growth line in enamel, the striae of Retzius, represents a biological rhythm related to body size in mammals. This rhythm can range in humans by ca. 6-12 days, and it is hypothesized that larger people are nearer the 6-day end of the range, while smaller people are nearer to 12-days. This hypothesis is reasonable because the striae of Retzius rhythm is also that same biological rhythm required to form bone. The number of microanatomical bone cell spaces, or lacunae, within bone is related to growth rate and body size in mammals, and so a person with a short rhythm should have more lacunae per unit volume of bone than a smaller person with a longer rhythm and slower bone development. These ideas are being tested using bone and tooth specimens collected from gross anatomy cadavers of the University of Malawi College of Medicine and life history information gleaned from questionnaires given to donor next of kin. In so doing, the first publicly accessible bone and tooth tissue bank of sub-Saharan Africans of known life history will be established.
