Patterns of dystrophin gene deletions in DMD/BMD patients were compared in
four populations: Turks (n = 146 deletions), Europeans (n = 838), North Ind
ians: (n = 89), and Indians from all over India (n = 103). Statistical test
s revealed that there are differences in the proportions of small deletions
. In contrast, the distribution of deletion breakpoints and the frequencies
of specific deletions commonly observed in the four populations are not si
gnificantly different. The variations strongly suggest that sequence differ
ences exist in the introns; and the differences are in agreement with genet
ic distances among populations. The similarities suggest that some intronic
sequences have been conserved and that those will trigger recurrent deleti
ons, since it is unlikely that gene flow would disperse the deleted chromos
omes. which vanish from the gene pool in a few generations.