DNA probes for human blood?

afc at gnv.ifas.ufl.edu afc at gnv.ifas.ufl.edu
Wed Nov 25 11:24:02 EST 1992


Hello all,

We need to determine the source of the blood meal from field-collected
mosquitoes.  Most people are using precipitin tests with polyclonal
antibodies, but this is ridiculously expensive.  We are already using
DNA probes to dot-blotted mosquito squashate to identify mosquito
species, so now we would like to use the same technique for blood meal
analysis.  The most important thing is whether the blood is human.  It
would also be nice to know if it were bird, mammal, or reptile otherwise,
but this is not critical.

A Japanese group has just reported success with this using a chunk of
a human globin gene with a Kpn repeat in it.

Questions:

Is Kpn the best repeat to use?  What about Alu?  We will be doing some
work in South America, so crossreaction with other primates is a minor
consideration.  Crossreaction with common mammals (cows, rodents, dogs,
etc.) would be very bad.  Sensitivity might be a problem, since there
won't be much DNA available, so we want a high copy repeat.

For detection of bird or reptile DNA, we can use a much lower copy number
repeat since red blood cells are nucleated.  Any suggestions? 

I assume that, as a last resort, we could label the antibodies and use
them to probe our dots blots (sort of a western dot blot).  Won't this
be much more sensitive than precipitin tests and save lots of money?
(I would still rather use DNA probes for everything, if I can.)

If anyone can help us with this problem, I would appreciate it.

Thanks,

Andrew Cockburn
USDA



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