These are the science and technology stories that “broke out” into popular media this week. Some of them may be fresh research, some are fresh reporting, and others are just plain interesting.
Ed Yong, writing for The Atlantic, looks at fascinating issue that’s sadly decimating the world’s largest creatures.
Over the past 50 million years, a group of small, hoofed mammals gradually evolved into today’s whales and dolphins. In the process, they gained much: a watery, planet-wide habitat and bountiful sources of food. But they lost a lot, too. Surrounded by endless blue, they became color-blind. Immersed in water, their sense of smell disappeared. And for some reason, they lost a gene called PON1.
For roughly 49.99993 of those 50 million years, whales had no reason to regret this bit of dropped DNA. Such losses happen all the time, and this gene—involved the the metabolizing of cholesterol—simply wasn’t needed by marine mammals. In fact, breaking the metabolic cycle that included the proteins coded by the PON1 gene likely represented an advantage for marine mammals of all sorts. While having it helps land mammals break down fats, not having it is suspected to be part of the complex set of trade-offs and modifications that allows sea-going mammals to hold their breaths for extended periods. So the gene is missing in whales, dolphins, seals and manatees.
But in the last 70 years, something very serious happened. Humans began filling the world with a class of chemicals called organophosphates. They’re used as pesticides, and while they’re not as immediately toxic to mammals as they are to most insects, they are still toxic. And fat-soluble. Getting them out of the body requires … PON1. Which marine mammals don’t have.
So an evolutionary trade off made millions of years at a time long before the first ape, much less the first human, had appeared on the planet means that the pesticides we send flowing into the seas build up in the bodies of marine mammals, and they have no system for purging these toxins.
Even partially aquatic mammals, like the beaver and sea otter, have lost PON1. And in the modern era of organophosphates, that loss could take a newfound toll.
Yong writes a fascinating tale of evolution, human activity, and the unforeseen consequences of both. Go read the whole thing. It’s well worth it.
Then come inside. There’s more.
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