Coevolutionary networks: a novel approach to understanding the relationships of humans with the infectious agents

Abstract

Human organism is interpenetrated by the world of microorganisms, from the conception until the death. This interpenetration involves different levels of interactions between the partners including trophic exchanges, bi-directional cell signaling and gene activation, besides genetic and epigenetic phenomena, and tends towards mutual adaptation and coevolution. Since these processes are critical for the survival of individuals and species, they rely on the existence of a complex organization of adaptive systems aiming at two apparently conflicting purposes: the maintenance of the internal coherence of each partner, and a mutually advantageous coexistence and progressive adaptation between them. Humans possess three adaptive systems: the nervous, the endocrine and the immune system, each internally organized into subsystems functionally connected by intraconnections, to maintain the internal coherence of the system. The three adaptive systems aim at the maintenance of the internal coherence of the organism and are functionally linked by interconnections, in such way that what happens to one is immediately sensed by the others. The different communities of infectious agents that live within the organism are also organized into functional networks. The members of each community are linked by intraconnections, represented by the mutual trophic, metabolic and other influences, while the different infectious communities affect each other through interconnections. Furthermore, by means of its adaptive systems, the organism influences and is influenced by the microbial communities through the existence of transconnections. It is proposed that these highly complex and dynamic networks, involving gene exchange and epigenetic phenomena, represent major coevolutionary forces for humans and microorganisms

Coadaptation and malaria control

“…This is a collective denomination for genes or gene sequences capable to invade host genomes and cause alteration of their structure or functions (Tosta 2001). Retroelements are the best known infectrons in human genome.…”

O pensamento epidemiológico evolutivo sobre as infecções

“…A esse fenômeno costuma-se dar o nome de pirataria molecular. Com a finalidade de abranger a variedade de DNA exó-geno e interferir com a organização e o funcionamento do genoma primitivo, Tosta 18 …”

“…Se ambos tendem à incorporação, os dois genomas se modificam, e, assim, surge nova entidade mórbi-da. Em outros termos, ambos evoluem (Tosta,18 2001). Não padecem dúvidas sobre a plasticidade genômica.…”

Infectrons and coevolution

“…This term was coined to encompass the broad array of exogenous DNAs that invade a genome and interfere with its structure or organization, and, therefore, with its function 19 . Infectrons are entire genomes or part of it, have either a short or a lifelong effect on host genome, are originated from any source of DNA, and invade any genome, either by vertical (germline cells) or horizontal (somatic cells) transfer.…”

“…Este termo inclui a grande variedade de ADNs exógenos que podem invadir um genoma e interferir com sua estrutura ou organização e, em conseqüência, com sua função 19 . Os infectrons são genomas completos ou parte deles, apresentam um efeito transitório ou permanente sobre o genoma hospedeiro, são constituídos por ADN de qualquer fonte, e capaz de invadir qualquer genoma, tanto por transmissão vertical (células da linhagem germinativa), quanto horizontal (células somáticas).…”