小精灵926
DNA:脱氧核糖核酸又称去氧核糖核酸,是一种生物大分子,可组成遗传指令,引导生物发育与生命机能运作。主要功能是信息储存,可比喻为“蓝图”或“食谱”。其中包含的指令,是建构细胞内其他的化合物,如蛋白质与核糖核酸所需。带有蛋白质编码的DNA片段称为基因。DNA亲子鉴定就是拿两个鉴定的DNA看是不是有血缘关系
菜菜~小
DNA FingerprintingDNA is the genetic material found within the cell nuclei of all living things. In mammals the strands of DNA are grouped into structures called chromosomes. With the exception of identical siblings (as in identical twins), the complete DNA of each individual is unique.DNA fingerprinting is sometimes called DNA typing. It is a method of identification that compares bits of DNA. A DNA fingerprint is constructed by first drawing out a DNA sample from body tissue or fluid such as hair, blood, or saliva. The sample is then segmented usingenzymes, and the segments are arranged by size. The segments are marked with probes andexposed on X-ray film, where they form a pattern of black bars the DNA fingerprint. If theDNA fingerprints produced from two different samples match, the two samples probably camefrom the same person.DNA fingerprinting was first developed as an identification technique in 1985. Originally used to detect the presence of genetic diseases, it soon came to be used in criminal investigations and legal affairs. The first criminal conviction based on DNA evidence in the United States occurred in 1988. In criminal investigations, DNA fingerprints derived from evidence collected at the crime scene are compared the DNA fingerprints of suspects. Generally, courts have accepted the reliability of DNA testing and admitted DNA test results into evidence. However, DNA fingerprinting is controversial in a number of areas: the accuracy of the results, the cost of testing, and the possible misuse of the technique.The accuracy of DNA fingerprinting has been challenged for several reasons. First, because DNA segments rather than complete DNA strands are "fingerprinted"; a DNA fingerprint may not be unique; large-scale research to confirm the uniqueness of DNA fingerprinting test results has not been conducted. In addition, DNA fingerprinting is often done in private laboratories that may not follow uniform testing standards and quality controls. Also, since human beings must interpret the test, human error could lead to false results.DNA fingerprinting is expensive. Suspects who are unable to provide their own DNA toexperts may not be able to successfully defend themselves against charges based on DNA evidenceWidespread use of DNA testing for identification purposes may lead to the establishment of a DNA fingerprint database.