PCR contamination

T.J. Fitzmaurice tjf11 at cus.cam.ac.uk
Tue Feb 21 08:48:17 EST 1995


In article <3ib0an$ssr at panix.com>, James Scutero <jscutero at panix.com> wrote:
>>
>Names of viruses change with time. HHV-6 was originally called HBLV-I until
>it was found to primarily kill T cells. After being named HHV-6, it was
>further broken down to variants A and B. Variant B is linked to exanthem
>subitum, a benign febrile illness of early childhood. Variant A is found in
>immunocompromised patients. And:
And your point here is?????? It just seems way off what I was talking about.

>same diseases. Still, they are considered to be Variants of the same virus.
>How are the names of viruses chosen? When is a virus considered to be called
>a "Variant" of another virus? Is genetic sequencing the determining factor
>for the final taxonomic place for a virus, and if so, based on what criteria?
Once the identity of a virus is well enough established, its name gets 
recognised, these days I believe the original researcher has a say in what
the virus is called, plus human herpes are assigned a number.
Variants I believe are based on serological crossreactivity,genetic changes
which are little more than deletions or changes in tandem repeats, 
antigenic indentity etc. Ed is probably best to answer this that I know of 
in this forum.
>>Thats like saying chicken pox is caused by Herpes simplex.
>>And then arguing VZV is closely related so what you said is all right.
>
>Well, the only way to find out is to study an electron micrograph of HHV-6
>(variants A and B) and compare it to KSHV.
Morphology is and has not been an absolute is taxology since Archimedes. A
useful tool yes, but an absolute, no. 
>Have you done a comparision of the
>genetic sequences of KSHV and HHV-6(A and B) using GENEBANK?

Yes I have actually. Here are the results. There are two published sequnces
in KSHV, one larger than the other. The second smaller fragment carried
similarities to a few minor human transferase genes. the larger one was more
elucidating. 
Homology is listed to several genes in Epstein Barr Virus, running at about 65%
homology. Next in order of similarity came Herpvesvirus saimiri,Bovine herpes 4
AHV-1, HSV-1, human cytomegalovirus and then Equine herpes virus 1.

HHV-6 is nowhere on that list..... Sorry
Go check it yourself.
>
>I THINK you should tell me how these two viruses, HHV-6 and KSHV, 
>differ physically and genetically.
>
>-James M. Scutero
Well since you seem to be putting them together, the onus unfortunately
is on you to prove their indenticality on these issues. Similar they may be
but the evidence s they are not the same. See the genbank results I quote above.

Tim



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