ANCIENT HLA GENES FROM 7,500-YEAR-OLD ARCHAEOLOGICAL REMAINS

IN the past decade there has been increasing interest in cloning DNA from ancient and preserved tissues 1-6. Most studies, however, have focused on mitochondrial or chloroplast genes, present at hundreds to thousands of copies per cell compared with one or two for each nuclear gene 7-9. With a probe containing Alu repeat sequences, Paabo isolated a 3.4-kilobase DNA fragment from a 2,400-year-old Egyptian mummy 10 which was subsequently shown to contain an intron of the nuclear gene HLA-DQA (ref. 11). Here we report a more targeted approach to the characterization of nuclear genes from archaeological specimens. The Windover pond of central Florida has provided skeletal and soft tissue remains from 165 humans, radiocarbon-dated to be 6,990-8,130 years old 12-14. Using DNA obtained from one individual we have characterized segments from six nuclear genes: that for beta-2-microglobulin and five members of the class I HLA heavy chain gene family. Distinctive patterns of nucleotide substitution in the cloned heavy chain gene segments permit tentative assignment of the HLA-A,B type of the ancient individual.