Andrew: Microbes are everywhere, so a coping mechanism to survive in a world of bacteria seems evolutionary necessary. We traditionally consider our “anti-non-self ” immune system as that coping mechanism, but organisms may have also evolved a system of stable microbial coexistence. How? By inter-species gene regulation.

This is particularly interesting to me because it shows how genomics isn’t about closed, procedural, self-describing systems. Rather, genomics is contextual, recursive, and non-deterministic, like how DNA is part of the phenotype described by the genotype described by that DNA. Even better, the confusion isn’t limited to a single organism’s genome: here, squid genomic expression is modified by symbiotic bacteria to create an stable environment for the microbes and a novel phenotypic advantage for organism. So, evolutionary selection may act not only on what potential phenotypes a genome describes itself, but how that genome may be expressed as influenced by the expression of other organisms’ genomes and the environment.

…And you want to go back to “genes determine traits?” Boring!

Though bacteria are everywhere — from the air we breathe and the food we eat to our guts and skin — the vast majority are innocuous or even beneficial, and only a handful pose any threat to us. What distinguishes a welcome microbial guest from an unwanted intruder?

Research from the University of Wisconsin-Madison suggests the answer lies not with the bacteria, but with the host.

A study appearing online this week in the Proceedings of the National Academy of Sciences may help reveal what sets a platonic relationship apart from a pathogenic one. In the paper, researchers from the UW-Madison School of Medicine and Public Health and the University of Iowa identify a slew of microbe-induced genetic changes in a tiny squid, including a set of evolutionarily conserved genes that may hold the secrets to developing a mutually beneficial relationship.

“Interactions of animals with their microbiota have a profound impact on their gene expression, and to create a stable association with a microorganism requires a lot of conversation between the microbe and the host,” says UW-Madison medical microbiologist Margaret McFall-Ngai, senior author of the new study. … Continue Reading »