Investigators have asked the families of people missing in last Tuesday's attack on New York's World Trade Center to bring in toothbrushes and hairbrushes that may contain DNA to help identify bodies and body parts found in the rubble.

　　　More than 6,000 people are still missing. Of 159 bodies received, only 99 have been identified. Fifteen of the identities were established by examining partial remains.

　　　With rescuers sometimes finding just fragments of human bodies, they hope that advanced technology will allow them to identify the missing using DNA gleaned from hair from combs or razors.

　　　New York's chief medical examiner, Charles Hirsch, said police would manage the collection of personal items like toothbrushes and underwear to identify victims by their DNA.

　　　Like the fingerprints, each person has a unique DNA profile, or what is sometimes called a DNA "fingerprint". DNA fingerprinting requires several steps, including recovery of DNA from the cells or tissues of the body. For example, the amount of DNA found at the root of one hair is usually sufficient.

　　　DNA fingerprinting has also been used in criminal cases, with a match of a suspect's DNA with DNA from a crime scene being used to convict suspects. The technology has also been used to clear the innocent. 从牙刷和梳子上要DNA 　　9月11日，纽约世界贸易中心遭到恐怖袭击之后，调查人员已经通知遇难者家属提供失踪人员曾经使用过的牙刷和梳子，因为牙刷和梳子上会带有失踪者的DNA，调查人员可以通过对DNA的分析来确认在废墟中找到的尸体和尸体残骸的身份。

　　　到目前为止，仍有超过6000人下落不明。在已经发现的159具尸体中，只有99具被确认了身份，这其中15具尸体是通过对尸体残留部分的辨认确定身份的。

　　　有时候救援人员只能找到失踪者的尸体碎片，所以他们希望能够运用高科技手段通过从失踪者用过的梳子或者剃须刀上收集到DNA，以此来确认失踪者的身份。

　　　就像指纹一样，每个人的DNA排列都是不同的，因而有时候DNA又叫做DNA“指纹”。DNA的鉴定需要几个步骤，其中包括从身体的细胞或组织中找到DNA分子。例如，一根头根上找到的DNA分子通常情况下就足以确定身份了。