Physical mapping of 3′ PAX6 deletions.
(a) Pulsed-field gel of lymphoblastoid genomic DNA from
cases 1 and 2 and a normal reference individual (R) hybridized with
probes pFix2RS1 and p32.1. These probes detect one 1400-kb
NotI (N) fragment and two SacII (S)
fragments, which are 350 kb (centromeric) and 1050 kb (telomeric). The
internal SacII (S*) site is partially cleaved (22, 32).
The second SacII fragment in the reference (R) lane
reflects a likely sequence polymorphism. (b) Restriction
map showing hybridization probes and deletion breakpoints relative to
PAX6. Probe pC1PBRI detects an altered
NotI fragment in case 1 but not case 2 (data not shown).
The deletions encompass breakpoints of the HV reciprocal translocation
and the SGL paracentric inversion (arrowheads), which are located,
respectively, 124 kb and 85–100 kb from the 3′ end of
PAX6 (22, 33, 34).