What results from a blunt end restriction digest?

The result of a blunt end restriction digest is that fragments are cut at the same positions on complementary strands. This means that when a restriction enzyme creates a blunt end cut, it does so symmetrically, producing fragments that have no unpaired bases or overhangs at the ends.

This uniformity allows the fragments to have a well-defined endpoint, which is crucial in various molecular biology applications, especially cloning. In cloning processes, the ability to align and combine fragments precisely is important, and blunt ends facilitate this by providing straightforward pairing with other blunt-ended fragments. The symmetrical nature of the cuts ensures that the resulting DNA fragments will match exactly at their ends, making ligation between them feasible under appropriate conditions.

Other options, such as fragments with overhanging ends or those that cannot be ligated, do not apply in the case of blunt ends, as blunt end cuts do not create any protruding nucleotides that could otherwise interfere with the process of ligation.