On the general theory of the origins of retroviruses.
BACKGROUND
The order retroviridae comprises viruses based on ribonucleic acids (RNA). Some, such as HIV and HTLV, are human pathogens. Newly emerged human retroviruses have zoonotic origins. As far as has been established, both repeated infections (themselves possibly responsible for the evolution of viral mutations (Vm) and host adaptability (Ha)); along with interplay between inhibitors and promoters of cell tropism, are needed to effect retroviral cross-species transmissions. However, the exact modus operandi of intertwine between these factors at molecular level remains to be established. Knowledge of such intertwine could lead to a better understanding of retrovirology and possibly other infectious processes. This study was conducted to derive the mathematical equation of a general theory of the origins of retroviruses.


RESULTS
On the basis of an arbitrarily non-Euclidian geometrical "thought experiment" involving the cross-species transmission of simian foamy virus (sfv) from a non-primate species Xy to Homo sapiens (Hs), initially excluding all social factors, the following was derived. At the port of exit from Xy (where the species barrier, SB, is defined by the Index of Origin, IO), sfv shedding is (1) enhanced by two transmitting tensors (Tt), (i) virus-specific immunity (VSI) and (ii) evolutionary defenses such as APOBEC, RNA interference pathways, and (when present) expedited therapeutics (denoted e2D); and (2) opposed by the five accepting scalars (At): (a) genomic integration hot spots, gIHS, (b) nuclear envelope transit (NMt) vectors, (c) virus-specific cellular biochemistry, VSCB, (d) virus-specific cellular receptor repertoire, VSCR, and (e) pH-mediated cell membrane transit, (downward arrow pH CMat). Assuming As and Tt to be independent variables, IO = Tt/As. The same forces acting in an opposing manner determine SB at the port of sfv entry (defined here by the Index of Entry, IE = As/Tt). Overall, If sfv encounters no unforeseen effects on transit between Xy and Hs, then the square root of the combined index of sfv transmissibility (radical |RTI|) is proportional to the product IO* IE (or approximately Vm* Ha* sum Tt* sum As*Omega), where Omega is the retrovirological constant and summation operator is a function of the ratio Tt/As or As/Tt for sfv transmission from Xy to Hs.


CONCLUSIONS
I present a mathematical formalism encapsulating the general theory of the origins of retroviruses. It summarizes the choreography for the intertwined interplay of factors influencing the probability of retroviral cross-species transmission: Vm, Ha, Tt, As, and Omega.
Unit of Theoretical Biology, Division of Molecular Pathology, Department of Pathology, School of Biomedical Sciences, College of Health Sciences, Makerere University, PO Box 7072, Kampala, Uganda. wmisaki@yahoo.com
Misaki
M
Wayengera
D000818:Animals; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D006801:Humans; D008954:Models, Biological; D018741:Replication Origin / Q000502:physiology; D012190:Retroviridae / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D053150:Simian foamy virus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
D004279:DNA, Viral