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本帖最后由 pan123au 于 2018-12-21 07:09 编辑
Xueling77 发表于 2018-12-20 23:23 
从你之前连为什么报告里会出现unrelated Asian 都不清楚,大概你也不是DNA专家吧。我早就承认我是吃瓜群 ...
这个所谓的血迹 跟 只有跟林家的人比才有意义,跟unrelated Asian比较一点意义都没有.
the DNA is isolated from the cells and millions of copies are made, using a method called 'polymerase chain reaction', or PCR.
PCR uses a naturally occurring enzyme to copy a specific stretch of DNA over and over again. Having lots of DNA makes the genetic code easier to analyse.
The DNA molecules are then split at particular locations to separate them into known 'chunks' and the code at those specific points is analysed to create a DNA fingerprint. The fingerprints from the two different samples are then compared to see if they match.
There is always a small chance that two different people's genetic markers could be the same, especially if they are related.
To reduce the chance of error, scientists test more than one genetic marker. The more identical markers there are in two samples, the more accurate the test.
However, testing more markers takes more time and is more expensive. Forensic DNA tests usually examine six to ten markers. The chances that two unrelated people have identical profiles is less than one in one billion.
http://www.bbc.co.uk/science/0/20205874
http://www.forensicsciencesimplified.org/dna/how.html |
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