Analysis of Heritable Dental Traits in Native Americans
A Preliminary Study
With funding from the Cynthia and George Mitchell Foundation, TARL has initiated an analysis of heritable traits in Native American dentition in Texas modeled on Christy Turner’s massive landmark analysis of heritable discrete (or non-metric) dental traits on modern and prehistoric Native Americans from southwestern US and adjacent Mexico. Turner, a physical anthropologist at Arizona State University, was able to identify and quantify clusters of these heritable traits, some of which correspond to modern tribal groups. Turner was also able to recognize prehistoric population movements and was in some cases able to identify individual communities whose populations clearly differed significantly from nearby communities that appeared otherwise identical archeologically.
The remarkable geographic and environmental diversity of Texas, together with its long history of Native American occupation, make it highly probable that an analysis of heritable dental traits will identify genetic relationships and differences not otherwise recognizable. This will provide an unparalleled opportunity for assessing relationships among prehistoric Texans, particularly when the data are integrated with that from the Southwest and, over time, with data from other adjacent areas.
No other kind of data (other than DNA which requires destructive analysis) can yield the level of specificity derivable from heritable dental traits. Heritable traits reveal attributes about people that may be masked by traditional archeological data. Turner (1993) noted that key heritable dental traits are particularly useful for this kind of analysis for several reasons.
“First, they are nearly free of sex influence and have no age changes, so every individual in a series can be pooled to maximize sample size. Second, all studies to date indicate that the traits possess a high genetic component for their occurrence and expression. Third, all are relatively independent. Fourth, numerous studies have shown that these traits are evolutionarily conservative and are thus as powerful as single gene traits, like blood groups, for measuring inter-group affinity and relationships.”
In addition, as Turner pointed out, because teeth are generally the best preserved skeletal elements, heritable traits expressed in them are more likely to be observable than heritable traits in other skeletal elements. Indeed, dentition is sometimes the only preserved portion of a skeleton. Importantly, collection of data on heritable dental traits is nondestructive and is replicable.
TARL currently holds approxiigh probability of good observations of crown size, number of roots, and certain other non-metric traits. A smaller proportion (83%) has a high probability of yielding data on cusp attributes. Accounting for those with poor preservation, inaccessible portions, and other issues, approximately 1000 sets of remains are likely to yield meaningful observations. Approximately one-third of these are affiliated with federally recognized Native American tribes or are under the control of federal government agencies.
For our project, data collection and analysis is being done by physical anthropologist Matt Taylor who has conducted extensive analysis of prehistoric skeletal remains from the Texas coastal areas (most at TARL) as well as elsewhere in the US. Targeting geographically dispersed sites/collections, the initial sample will focus on some 500 sets of remains. Matt has already coded four large prehistoric cemeteries along the Texas coast and has begun work on another.
Turner, Christy G., II
1993 Southwest Indian Teeth. National Geographic Research and Exploration 9(1):32–53.