Skip to main content

How Low Can It Go?

How many genes are needed to sustain an organism? As Carl Zimmer notes in the New York Times that number may be surprisingly small and, ultimately, irrelevant.

Tremblaya princeps only has 120 protein-coding genes, but that the organism is quite specialized, Zimmer notes. It lives only on the mealybug, in a co-dependent fashion. But, he adds, a third player — a bacterium called Moranella endobia, coming in with 406 genes — is actually needed for T. princeps to transform sap into food for the mealybug. As these organisms became entwined, they lost genes they once had.

"[T]he concept of a minimal genome, while provocative, is ultimately a dead end," Zimmer says. "Life does not exist in a laboratory vacuum, where scientists can pare away genes to some Platonic purity. Life exists in a tapestry, and the species with the smallest genomes in the world survive only because they are nestled in life's net."

The Scan

And For Adolescents

The US Food and Drug Administration has authorized the Pfizer-BioNTech SARS-CoV-2 vaccine for children between the ages of 12 and 15 years old.

Also of Concern to WHO

The Wall Street Journal reports that the World Health Organization has classified the SARS-CoV-2 variant B.1.617 as a "variant of concern."

Test for Them All

The New York Times reports on the development of combined tests for SARS-CoV-2 and other viruses like influenza.

PNAS Papers on Oral Microbiome Evolution, Snake Toxins, Transcription Factor Binding

In PNAS this week: evolution of oral microbiomes among hominids, comparative genomic analysis of snake toxins, and more.