Identification of LID 1–6 by L1 display and verification of LID dimorphism. (a) L1 display. The products of the second round of PCR amplifications were Southern blotted and probed with oligonucleotide Hb (Fig. 1 a). Digital photographs (Kodak DC40) of the sections of the autoradiograms that depict LID 1–6 are shown. Each lane represents the results obtained from one individual.(b) PCR amplification with primers ACA and 3FPa. Digital photographs of ethidium bromide-stained gels (Kodak DC40) are shown.(c) Southern blot of AccI-digested genomic DNA hybridized with 3′-flanking probes. The probes were generated by amplifying the non-L1Hs 3′-flanking DNA of the cloned LIDs with primers 3FPa and 3FPb and tailing the products by the addition of [α-³²P]dCTP with terminal transferase. Digital photographs of the autoradiograms of the hybridized blots are depicted. Fragments representing both the empty alleles (slower mobility) and the occupied alleles (faster mobility) can be seen in the blots hybridized with the 3′-flanking probes from LID 1, 2, 4, 5. The two bands in the Ca-2 and Dr samples of the LID-1 blot (positions indicated by short lines) are located extremely close to one another. The absence of fragments for the Ca-1 samples in the LID-2 and LID-4 blots was due to an insufficient loading of DNA. (d,e) PCR amplification of LID 1–6 with 5′- and 3′-flanking primers. Genomic DNA was amplified with primers 3FPa and 5FP. For each LID, 200 ng genomic DNA was amplified with the LID-specific primers 5FP and 3FPa. The arrowheads indicate the location of the amplified products of the empty alleles. The larger bands are the amplified products of the filled alleles. Digital photographs of the ethidium bromide-stained gels(d) or the autoradiograms of the gel after blotting and hybridization with probe Hb (e) are shown.