The Ed's Up #91
Single-Celled Creature Has Eye Made of Domesticated Microbes
"The strangest eyes in the ocean—eyes so weird that we can’t even be sure that they are eyes—belong to a group of rare, free-swimming algae called warnowiids. Each consists of a just one round cell, so small that a few hundred of which could fit in this full stop. Under the microscope, each warnowiid contains a conspicuous dark dot. This is the ocelloid. It consists of a clear sphere sitting in front of a dark red strip, and has components that resemble a lens, an iris, a cornea, and a retina. Eyes are meant to be animal inventions. They’re supposed to comprise many cells. They are icons of biological complexity. And yet, here’s a non-animal that packs similar components into its single cell. Gregory Gavelis from the University of British Columbia has now discovered something about the ocelloid that’s even weirder. At least two of its components—the “retina” and the “cornea”—seem to be made from domesticated bacteria." (Image: Greg Gavelis)
Hot Wild Dragons Set Sex Through Temperature Not Genes
"At room temperature, a bearded dragon’s sex depends on two chromosomes. If they have two Z chromosomes, these lizards develop as males. Those with a Z and a W become females. But raise the thermostat up a few notches, and something different happens. If a clutch of dragon eggs are incubated at 34 degrees Celsius, their bodies ignore the usual instructions from their sex chromosomes. Even if half of them are genetically male (ZZ), all of them will hatch as females.Clare Holleley from the University of Canberra found some of these “sex-reversed” ZZ females in the wild, and bred them with the usual ZZ males. All the offspring from these crosses should have two Z chromosomes, so you might guess that all of them would turn out male. In fact, their chromosomes didn’t matter at all. Instead, their sex depended entirely on the temperature at which they are incubated. In a single generation, these lizards had evolved a radically different way of determining their sex—one in which their genes completely cede control to the heat of the world." (Image: Arthur Georges)
More good reads
- “Once that fluid had been a mortal danger; now it was a valuable commodity.” Erika Check Hayden writes about the biological secrets hidden in the blood of Ebola survivors, and a literal race to get their samples on a plane. Thrillingly structured, keenly reported, beautifully written—this is an A+ journalist operating at the top of her game.
- In 1950, the US military laced Karl the Fog with opportunistic bacteria to simulate a bioterror attack on San Francisco. By Rebecca Kreston.
- Sometimes chimps dance and then get very peaceful at waterfalls. What are they feeling? Brandon Keim discusses.
- Rewrite the textbooks! No, seriously, rewrite them. Because they're wrong about psychology’s most famous case study. By Christian Jarrett.
- On Crohn’s, MERS, Creutzfeld-Jacob, and the etiquette of naming diseases. Great Alastair Gee piece.
- This is great: Did Kirsten Tatlow at the NYT interviewed several Chinese bioethicists about the country's attitude to CRISPR embryo-editing
- "That translucent tube is the larva's highly mobile anus, which is a sentence I just wrote." Nick Stockton on the wonderful colour-changing tortoise beetle.
- "Who Owns Your Face?" Robinson Meyer on the ethics of facial recognition technology
- Matthew Francis is spot-on: let's stop deifying Nobel laureates.
- The most common vertebrate on the planet is... wait, what is that? Amazing story by William J Broad
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-Ed