reply to post by moniesisfun
Can you give me an example of an individual adaptation which are "available to the community and critical to survival of the species, whether or not
the individual survives".
Okay. Off the top of my head…
The most well-known and fully substantiated examples involve antibiotic and pesticide resistance in bacteria - resistance is conferred by
"horizontal gene transfer" and NOT vertically by inheritance, contrary to earlier assumptions and 'common descent' doctrine. …When one bacteria
develops resistance, the adaptation spreads through the entire community like wildfire - or the common cold. Such genes may be considered "infectious
DNA." [NOTE: Resistance is not inherited so neither reproduction nor ongoing life is required from the originator host.]
Horizontal gene transfer
* ISS: The direct uptake of foreign genetic material by cells and incorporation into the cells’
* Wiki: also lateral gene transfer (LGT) or transposition refers to the transfer of genetic
material between organisms (by means) other than vertical gene transfer (inheritance).
* USDA: Transmission of DNA between species, involving close contact
between the donor's DNA and the recipient, uptake of DNA by the recipient, and stable incorporation of the DNA into the recipient's genome.
There are several mechanisms for horizontal gene transfer:
* Transformation, the genetic alteration of a cell resulting from the introduction, uptake and expression of foreign genetic material (DNA or
RNA). This process is relatively common in bacteria, but less so in eukaryotes. Transformation is often used in laboratories to insert novel genes
into bacteria for experiments or for industrial or medical applications. See also molecular biology and biotechnology.
* Transduction, the process in which bacterial DNA is moved from one bacterium to another by a virus (a bacteriophage, or phage).
* Bacterial conjugation, a process in which a bacterial cell transfers genetic material to another cell by cell-to-cell contact.
* Gene transfer agents, virus-like elements encoded by the host … (ie. transposons)
Transposons are quite interesting - long thought to be "junk DNA," they are now recognized as rather important. (Understatement.)
a segment of DNA that can move from one place to another in a cell's genome or between a bacterial cell and a plasmid or virus. Viruses may even
carry a transposon from one bacterium to another. Also called jumping gene, transposable element.
Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.
As viruses carry transposons from one bacteria to another, and prions from one human host to another, we can infer that viruses likely carry
transposons between humans as well.
Horizontal gene transfer revolutionized evolutionary theory. The "universal phylogenetic tree" is now best understood as a network - and visualizing
adaptation as part of an evolutionary network involves recognizing that there's likely more than one single step involved in any successful
With regard to how horizontal gene transfer affects evolutionary theory (common descent, universal phylogenetic tree) Carl Woese says:
"...But that was before horizontal gene transfer (HGT), which could offer an alternative explanation for the universality of biochemistry, was
recognized as a major part of the evolutionary dynamic. In questioning the doctrine of common descent, one necessarily questions the universal
phylogenetic tree. That compelling tree image resides deep in our representation of biology. But the tree is no more than a graphical device; it is
not some a priori form that nature imposes upon the evolutionary process. It is not a matter of whether your data are consistent with a tree, but
whether tree topology is a useful way to represent your data. Ordinarily it is, of course, but the universal tree is no ordinary tree, and its root no
ordinary root. Under conditions of extreme HGT, there is no (organismal) "tree."
Evolution is basically reticulate (forming a network)."
Sorry old buddy - no matter where I start, I keep getting back to the same place: we need to rethink our understanding of disease. We for SURE should
not euthanize any "useless eaters" because they just may carry the adaptation our species needs to survive - and we do NOT yet understand the
complexities of transfer.