Sl. Page et al., BREAKPOINT DIVERSITY ILLUSTRATES DISTINCT MECHANISMS FOR ROBERTSONIANTRANSLOCATION FORMATION, Human molecular genetics, 5(9), 1996, pp. 1279-1288
Robertsonian translocations are the most common chromosomal rearrangem
ents in humans. The vast majority of the ten possible nonhomologous ty
pes of Robertsonian translocations ascertained are rob(13q14q) and rob
(14q21q). Recombination between homologous sequences on nonhomologous
chromosomes has been proposed as a mechanism leading to the preferenti
al formation of rob(13q14q) and rob(14q21q). However, little evidence
exists to indicate whether the remaining less common Robertsonian tran
slocations form through a similar mechanism. To better elucidate the m
echanisms involved in Robertsonian translocation formation, we have us
ed fluorescence in situ hybridization to localize the breakpoints in 5
6 nonhomologous Robertsonian translocations. This study revealed highl
y variable locations of breakpoints in seven types of the less common
Robertsonians, while nearly all rob(13q14q) and rob(14q21q) analyzed d
isplayed breakpoints in the same locations, Therefore, this study prov
ides direct evidence that rob(13q14q) and rob(14q21q) form through a s
pecific mechanism, possibly involving homologous recombination, which
is distinct from the mechanism(s) that contributes to the formation of
the remaining types of Robertsonian translocations.