Figure 1.

Human diversity associated with a truncated Ta L1Hs element, as shown by an agarose gel chromatograph of the PCR products from a survey of the human genomic variation associated with L1HS7. Amplification of the pre-integration site of this locus generates a 130-bp PCR product; amplification of a filled site generates a 326-bp product (by use of flanking unique sequence primers). In this survey of human genomic variation, 20 individuals from each of four diverse populations were assayed for the presence or absence of the L1 element, with only the African American samples shown here; the control samples (gray lines) were TLE buffer (i.e., 10 mM Tris-HCl:0.1 mM EDTA), common chimpanzee, gorilla, and owl monkey DNA templates. Most of the individuals surveyed were homozygous for the presence of the L1 element; in addition, this particular L1 element was absent from the genomes of nonhuman primates.