how many white colonies should i choose to analyze? - TA coloning problem (Sep/11/2007 )

hi,everyone,
i want to know the genetic diversity of my environmental samples.so i TA-colonied their 16S rDNA fragments and transformed ligation into DH5α cells.my question is,what is the minimal number of postive white colonies should i choose to analyze?so that the results could represent the genetic diversity of my environmental samples,and how to determine the minimal number of postive white colonies ?what the actual mechanism is？
thank you very much!

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could anyone give me some suggestions？
thanks！

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i think that for every 3-4 clones screened you should get at least one positive clone, provided all ligation conditions have been fulfilled!

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thanks a lot.

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I would go for 10 clones minimum. I don't really trust TA-cloning. Yesterday, I did this TA cloning and I got 13 white colonies and 5 blue colonies on the plate. I thought it worked well (as I was cloning 7.2kb fragment). I chose 10 white colonies and guess what only 1 is positive. The example is different from your case, still I would suggest to go for 10..

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