extension

The short single-stranded stretch of nucleotides remaining on a double-stranded DNA molecule, following treatment with a restriction endonuclease which makes a staggered cut . The presence of these unpaired regions make the molecule more easily ligatable, and are thus important in gene cloning. Synonyms: protruding end; sticky end; overhang; cohesive end.

A Perl module that also pulls in compiled C or C++ code. More generally, any experimental option that can be compiled into Perl, such as multithreading.

A fully arranged sub-tour offered optionally at extra cost to buyers of a tour or cruise. Extensions may occur before, during, or after the basic travel program.