Abstract
Repair of double-strand breaks by gene conversions between homologous sequences located on different
Saccharomyces cerevisiae
chromosomes or plasmids requires
RAD51
. When repair occurs between inverted repeats of the same plasmid, both
RAD51
-dependent and
RAD51
-independent repairs are found. Completion of
RAD51
-independent plasmid repair events requires
RAD52
,
RAD50
,
RAD59
,
TID1
(
RDH54
), and
SRS2
and appears to involve break-induced replication coupled to single-strand annealing. Surprisingly,
RAD51
-independent recombination requires much less homology (30 bp) for strand invasion than does
RAD51
-dependent repair (approximately 100 bp); in fact, the presence of Rad51p impairs recombination with short homology. The differences between the
RAD51
- and
RAD50
/
RAD59
-dependent pathways account for the distinct ways that two different recombination processes maintain yeast telomeres in the absence of telomerase.