The data suggested that Karen’s two sons were related to her one brother, so they must, in theory, be related to her as well. Because Karen’s blood cells provided no match, the team of researchers decided to test some of her other tissues as well, including her hair and thyroid gland. The results are shown in Figure 2.
Figure 2. HLA haplotype testing of Karen’s blood, hair and thyroid tissues.

Figure credit: Originally published as Panel B of Figure 1 in: N. Yu et al., 2002, The New England Journal of Medicine: 346 (20), 1545–1552. Copyright © 2002 Massachusetts Medical Society. All rights reserved. Used with permission.
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