Are Viruses Living?

[Roy Goodacre]

In article <3nbbsj$i9r at d2.tufts.edu> welkin <wjohnson at opal.tufts.edu> writes:


>ED at molbiol.uct.ac.za ("Ed Rybicki") wrote:
>>
>> > From:          craigm at sanger.otago.ac.nz (Craig Marshall)
>> > Subject:       Re: Are Viruses Living?
>> 
>> > This seems to be a question with no answer. I would argue that there is
>> > some essential difference between the life of say, a bacterium and that
>> > of a virus. Viruses have the property of replication under very
>> > specific cirmcumstances (ie within a host cell) but I believe there
>> > some chemicals are capable of similar activity (but I can give no
>> > references for this claim). The property of replication is not
>> > equivalent to life in the sense that a bacterium (or whatever) is
>> > alive.
>> 
>> This is snowballing nicely...B-)
>> 
>> The above does not wash: the only difference between some bacteria and 
>> some viruses is that the former have membranes surrounding them and 
>> dividing them from the cell, and have their own tRNAs and ribosomes.  
>> Otherwise, the smallest bacteria / bacteria with the smallest genomes 
>> are as much dependent on being inside living cells (in that they are
>absolutely 
>> dependent on a wide range of substrates that they can't make) as are viruses, 
>> some of which (eg. phycodnaviruses, pooxviruses, iridescent viruses) 
>> have bigger genomes.  If you don't know WHICH chemicals are capable 
>> of self-replication, then it is a little ingenuous to make the 
>> claim...!  And do you consider mitochondria or chloroplasts to be a 
>> live?  All that separates them and free-living bacteria is a few 
>> hundred million years of evolution, after all.
>> 
>>And what about the endospores of species such
>as Bacillus and Clostridium?  They too are nothing
>until placed in the right environment.  If they are nlving
>they do a remarkable job of propagating themselves
>nonetheless.  

Yes ture but the point here is that they are viable and recoverable.  And 
yes viable does = life ....