The doxycycline is being given at low dose and has no direct effect on the mouse. It is being used to switch on and off the gene of interest - introduce a gene under expression control with doxycycline. This is a common way of doing gene regulation experiments in mice.

>doxycycline, a harsh antibiotic

Do you have any sources for it being harsh? I'm curious because I've been on antibiotics for 2 years (yes really) and this is the one I tolerate the best.

I was also on doxycycline for over 2 years, and barring a slightly dodgy tummy for the first 48 hours (fairly typical for antibiotics), I didn't notice any adverse affects. It did transpire that my doctor had 'forgotten' I was still on it though (I was only meant to be on it for 6 months!), so I did wonder if there were any adverse affects of taking it for that long!

> Yes, they “reverse” the condition, but only by the cessation of giving these little guys poison (doxycycline, a harsh antibiotic). This could have been called “high doses of doxycycline almost kills mice.”

You clearly do not understand how triggering genes with antibiotics work (like Ampicillin in the old days).