July 14, 2004
Ancient DNA and Pigmentation
A very exciting abstract from the 7th International Ancient DNA Conference.
Ancient DNA analysis for reconstruction of phenotypic traits from (pre)historic individuals.
Diane Schmidt, Susanne Hummel, Bernd Herrmann
Institute of Zoologie and Anthropology,
Department of Historical Anthropology and Human Ecology, University of Göttingen
Introduction
In our study, so-called SNPs (single nucleotide polymorphisms) are typed from (pre)historic human skeletal remains. The markers investigated here are correlated with human hair color and skin type. The investigation aims at establishing a tool for reconstructing certain aspects of the outer appearance of prehistoric humans by extracting and analyzing their ancient and degraded DNA. The analysis should be possible also for samples with strongly degraded DNA. For this purpose, a PCR based typing system was developed which enables to analyze eight single nucleotide polymorphisms located on chromosome 16 and 20 by generating short PCR products of less than 100 basepairs.
Materials and Methods
The analysis system was successfully applied to archaeological skeletal remains from a bronze age cave (Lichtenstein, approximately 900 B.C.), an early modern burial site (Goslar, approximately 1850 A.D.) and a medieval gravesite (Enger, approximately 900 A.D.) to determine hair colors and skin types from people of prehistoric times to reconstruct their physical appearance. To be able to draw conclusions about the individual's phenotype from the genetic data obtained, the data had to be compared to datasets from present-day populations. Since from modern studies no datasets for people from Central Europe were available, an investigation through cooperation with the Department of Dermatology to generate such data was carried out previous to the analysis of the archaeological samples.
The SNP typing system consisted of two quadruplex-PCRs for amplifying seven loci at the MC1R gene (encoding for melanocortin receptor 1) and one position at the ASIP (encoding for agouti signal protein). Subsequently, a single base extension reaction and fragment length analysis were carried out to detect potential polymorphisms.
Results and Discussion
The analysis of the present-day control sample revealed strong correlation between certain mutations an the MC1R gene and the red hair/fair skin phenotype. Individuals exhibiting these phenotypic traits can be distinguished from other phenotypes by typing the SNPs used for this investigation. The typing of the archaeological samples proved the suitability of the analysis system for degraded DNA. It was possible to successfully type seven individuals from the Bronze Age Lichtenstein cave and three individuals from the early modern site in Goslar, who could all be classified as persons with dark or blond hair and a skin that was not UV-sensitive. Out of the five individuals from the medieval collegiate church in Enger typed with the newly developed PCR system, one person can be characterized as having been red haired and fair skinned, the other individuals had dark or blond hair and a less UV-sensitive skin.