Joined: Oct. 2005
|Please tell me one subject you have a basic knowledge of ... just one.|
I have some knowledge in bacterial systematics. The Bacillus cereus group of spore-forming soil bacteria consists of (at least) three species, B. cereus, causing food poisoning through toxin production; B. thuringiensis, which infects and kills insect larva; and B. anthr*cis, the cause of anthr*x. The main difference between B. anthr*cis and the two less virulent species is the non-chromosomal genetic elements (plasmids) pXO1 and pXO2, which carry the anthr*x toxin genes. There is ample evidence for horizontal gene transfer (HGT) within and between these species. Furthermore, chromosome size varies by almost one order of magnitude within the group, and insertion/excision of very large plasmids in the chromosome have been reported.
This group is interesting in that it demonstrates:
i) large - but possibly differential - genetic plasticity. Case in point, B. anthr*cis isolates are, relative to natural isolates of the other two species, more genetically uniform. This (relative uniformity between worldwide isolates) also applies to the mosquitocidal israelensis subspecies of B. thuringiensis, which carries an insect toxin-production plasmid that is genetically related to pXO1 of B. anthr*cis.
ii) HGT can be accomplished in the lab, effectively transforming one species into another. This works both when "increasing information" (addition of plasmids) and "decreasing information" (curing - removal - of plasmids) within the cell.
We must note that the bacterial species concept is a bit different from that in "higher" (sexually reproducing) organisms, and is based traditionally on measurable traits (phenotype) such as cell shape, physiology/biochemistry, production of toxins and fermentation products etc., but today, any bacterial systematics is simply not done without comparative genetic data, whenever they become available (they do in virtually exponentially growing amount).
References are available on request (or search PubMed). Now one may put forward a couple of questions to a creationist (IDC, YEC or Flying Spaghetti Monsterist - Sauce be upon Him! ) -
-Why should we view the gazillion more or less different natural isolates within the Bacillus cereus group as each one separately created by YHWH/Allah/His Noodly Appendage? Or does YHWH/Allah/His Noodly Appendage not meddle with such unimportant organisms as the non-sexually reproducing ones?
-In case of Divine Creation, why was B. anthr*cis created with a point mutation in plcR, the gene encoding a virulence (disease-causing) regulation protein that in turn stimulates production of several extracellular toxins involved in infection? Note that B. anthr*cis carries functional copies of those other genes, but the corresponding proteins are not produced. Note also that we (scientists) have at least one putative hypothesis here (also available on request, but I´m interested in the Creationist answer first). If that point mutation is "allowed" within "microevolution", does it mean that YHWH/Allah/His Noodly Appendage will not meddle with such unimportant mutations - as compared to...what? Large-scale insertions/deletions (see above)?
That´ll do for now, I think it is enough to start up a fruitful discussion.
/The Rev. (no, not that Rev.)