strawberry DNA question

[smbla]

My 3rd grader and I have followed the protocol kindly suggested here https://www.sciencebuddies.org/science- ... shtml#help. We did one attempt where we crushed the strawberries very well in the plastic bag, and then added only water (no salt or detergent)- as a "negative control" for the extraction. In our "negative control" we could still see a whitish precipitate when we added alcohol- is it likely that this was also DNA, and that we had mechanically lysed enough cells to get this result without adding salt and detergent?
Thank you for any insight!

[deleted-141593]

It's possible. It's also possible that it is salt or sugar from the strawberries themselves. Does it look the same as the precipitate you get with salt/detergent?

[smbla]

Thank you for your reply!
It really looked like DNA, it was white and "cottony", and we could spoil it on to a skewer when we added alcohol. When we used salt and detergent there was more "cotton" formed, but this also had a hint of pink color (guessing it was pretty contaminated).

[deleted-141593]

So, given that there was less DNA-like material in the absence of salt/detergent could your child come up with a hypothesis to explain this? This would be a good exercise and a point to include in the interpretation of the results.

Cheers,
Colin