为什么我的dna总是提取失败，有和我同样情况的朋友吗，后来是怎样解决的哇

唾液里面的DNA主要来自口腔里的白细胞（74%）、少量来自脱落细胞。


 

第三次终于成功了。这次是通过按摩加咀嚼动作，先在口中积累了一些唾液后收集。一次就吐了1ml略多一些出来。可能真得是要靠唾液中的白细胞来提供DNA？另外一个因素是前两次是全基因组检测提取，这次是芯片检测提取。也许全基因组检测对DNA的量要求要多些？

可能是涌出太多的口水。
你直接用干净勺子刮口腔表皮，把收集到液体倒进去试试

好像有说法是唾液DNA主要来源是唾液里的白细胞而不是脱落的表皮细胞。网上看到下面的评论，不建议刮口腔内部，主要还是要让腺体分泌唾液后收集。到底哪种做法对呢？
If providing adequate sample volume is a challenge for you or someone you are assisting, the following may help increase saliva production:
Gently rubbing the outside of your cheeks
Making chewing motions with your mouth
Adding a small amount of sugar to the tip of your tongue
Smelling or imagining sour foods such as lemons
Thinking about your own favorite food
Biting or scraping your cheeks is not recommended; keep in mind that the majority of the cells analyzed in your saliva sample will not be epithelial cells from your cheeks but white blood cells that are found naturally in your saliva.