There is a close connection between microbes and humans experts believe about half of all human dna originated from viruses that infected and embedded their nucleic acid in our ancestors egg and sperm cells. Microbes occupy all of our body surfaces including the skin gut and mucous membranes. In fact our bodies contain at least 10 times more bacterial cells than human ones blurring. dna ルビdna ワクチンdna リクシェルdna 三重 螺旋dna 一致 確率dna レポートdna ルーシーdna ワールド 仮説