These are hula-hoop-shaped double-stranded units of DNA that can be moved easily from one cell to another.
它们是形似呼拉圈的双股dna单位，可以被轻易地从一个细胞转移到另一个细胞。
2
RNA molecules form doublestranded helices, just as do DNA molecules, by Watson Crick pairing of nucleotides on the two complementary strands of the helix.
RNA分子能像DNA分子那样形成双链螺旋，通过沃森·克里克配对，两个螺旋的核苷链互补。
3
Unlike nucleases, recombinases cut a double-stranded piece of DNA and then wait around on the exposed ends.