Paul,
Yes most of the literature contains circumstantially based evidence
of gene/genome transfer. I have to admit to being less familiar than I
wish with the literature in this area, I was writing from a position of
impression I have gotten just in "talking around the table" but I have come
up with a few possible recources on this topic:
Kellner, et. al. 1993. Transfer of genetic information from the
mycoparasite _Parasitella parasitica_ to its host _Absidia glauca_.
Current Genetics 23: 334-337.
Boyle, et al. 1993. Interspecific and intraspecific horizontal transfer of
Wolbachia in Drosophila. Science 260: 1796-1799
Goff. ??? Symbiosis, Interspecific Gene tranfer and the evolution of new
species: A case study in the parasitc red algae.
I need help on this one for the reference. Apparently this one was
photocopied from a book and the ref didn't get attached. (I'll keep
looking)
This next one is a short version though of the above:
Goff and Coleman, 1984. Tranfer of nuclei from parastie to its host.
Proceeding of the National Academy of Science. USA. 81: 5420-5424.
This is fascinating stuff (from any perspective) about one species of red
algae that parasitizes another and "infects" its host with its nuclei
eventually leading to the replacement of the hosts nuclei with its own
essentially converting the hosts cells into new parasitic cells which can
go on to infect others.
A little off the subject but still related:
Bianciotto et al. 1996 (just out this month). An obligately endosymbiotic
mycorrhizal fungus itself harbors obligately intracellular bacteria.
Applied and Environmental Microbiology 62: 3005-3010.
Although no evidence of transfer of genetic information is present the
concept of one organism inside another and that one inside another
certainly speaks of a complex biology which we are still only just
beginning to understand. Rather than being a shock it should be no
surprise if more and more cases of gene transfer come to light in coming
years.
It should be pointed out that none of these cases of direct evidence come
from examples of transfer from one Kindom to another. I won't give the
"phylogenetic" based evidences right now. I also was thinking in my
previous post of the many cases of apparent transfer of introns especially
in different algal groups. I'm off to the library for those. Tranfer of
elements from one subcellular component to another are also well know but
direct "in laboratory" evidences are few.
Excellent comments for which I wish I had time to comment on follow:
(I will comment later tonight when I am able to deal with the more friendly
environs of my home computer)
>
>Here's why this matters. I'll cite a nicely provocative paper by
>Schwabe and Warr:
>
> We believe that it is possible to draw up a list of basic
> rules that underline existing molecular evolutionary models:
>
> 1. All theories are monophyletic, meaning that they all
> start with the *Urgene* and the *Urzelle* which have given
> rise to all proteins and all species, respectively.
>
> 2. Complexity evolves mainly through duplications and
> mutations in structural and control genes.
>
> 3. Genes can mutate or remain stable, migrate laterally
> from species to species, spread through a population by
> mechanisms whose operation is not fully understand, evolve
> coordinately, splice, stay silent, and exist as pseudogenes.
>
> 4. Ad hoc arguments can be invented (such as insect vectors
> or viruses) that can transport a gene into places where no
> monophyletic logic could otherwise explain its presence.
>
> This liberal spread of rules, each of which can be observed
> in use by scientists, does not just sound facetious but
> also, in our opinion, robs monophyletic molecular evolution
> of its vulnerability to disproof, and thereby of its
> entitlement to the status of a scientific theory.
>
>(C. Schwabe and G. Warr, _Perspectives in Biology and Medicine_ 27
>[1984]: 465-485)
>
>Actually, Schwabe and Warr tell only half the story, and not even
>the scariest half.
>
>It is standard practice in molecular phylogeny construction to determine
>sequence alignment, the first analytical stage after the raw sequence
>data are obtained, more or less "by eye" -- and then to assess the
>reliability of that alignment by checking the phylogeny it produces. If
>you get a wild phylogeny: well, must be the wrong alignment.
>
>[A recent example of this sort of method, which should make anyone's hair
>stand on end, is Christopher Wills's paper "Topiary Pruning and Weighting
>Reinforce An African Origin for the Human Mitochondrial DNA Tree,"
>_Evolution_ 50 (1996): 977-989. Wills "prunes" (i.e., manipulates) human
>mtDNA sequence data iteratively until he gets the phylogenetic pattern he
>wants, because the starting pattern shows a starburst phylogeny with the
>primate outgroup located "very asymmetrically" from the root of the human
>starburst. Basically Wills tidies up the data until he gets the phylogeny
>he likes.]
>
>Tim Ikeda and I have correspondended a bit about this. (Tim, are you
>there?) But what I really want to know, re this post, is what
>experimental literature exists on lateral transfer.
>
>I'm guessing not much. If that's the case, then we don't really have
>decent grounds for constraining hypotheses of lateral transfer.
>
>Paul Nelson
>University of Chicago
>
>
>
>