Circular DNA in human and boar spermatozoa

Abstract

Circular DNA molecules were isolated from human and boar whole spermatozoa or spermatozoal nuclei and measured for size by electron microscopy. The DNA molecules derived from both mammals were heterogeneous in size ranging from 0.07 to 17 μm; nearly 75% of the molecules were ⩽0.5 μm in length. The mean lengths were 1.0 μm and 1.5 μm for circular DNAs isolated from human and boar spermatozoa, respectively. The origin and function of these molecules remains unknown.