AP BIOLOGY

Detailed explanation-1: -Resolvase is essential for a crucial step in DNA recombination, says Russell, because it is the molecule that allows two chromosomes to cross over. “It is one of the most important enzymes involved in genetic recombination, ” he says.

Detailed explanation-2: -The term resolvase is used to describe a related family of site-specific recombinases that function to excise (as a circle) a segment of DNA contained between two recombination sites (called res).

Detailed explanation-3: -Site-specific recombination requires a special enzymatic machinery, basically one enzyme or enzyme system for each particular site. Good examples are the systems for integration of some bacteriophage, such as l, into a bacterial chromosome and the rearrangement of immunoglobulin genes in vertebrate animals.