Amazing binturong-related breakthrough stuns binturologists worldwide

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Photo credit Jennifer Pack

Since ancient times, humans have wondered why the binturong, a south asian animal also known as a bear cat, smells like popcorn. Other varmints smell like musk, poop, urine, rotting things, or have their own particular brand of funk such as Wet Dog®. The binturong, however, smells distinctly like hot buttered popcorn.

Duke University researchers have now isolated the exact same compound from binturong urine that gives popcorn it’s aroma, 2-acetyl-1-pyrroline. The binturong gets plenty of this stuff on itself when it urinates. The scientists theorize that the purpose of the scent is to let other animals know, “A binturong was here.”

Let’s look at more pictures of binturongs.

Photo credit Mala C

Photo credit Mala C

 

Photo credit Josh More

Photo credit Josh More

New evolutionary mechanism found in primates

Photo credit Bald Wonder

Photo credit Bald Wonder

Researchers at Cornell University in New York and Bar-Ilan University in Israel found a new mechanism for gene mutation based on a family of virus-fighting enzymes called APOBECs. The interesting thing about APOBECs is that they fight viruses sort of the same way viruses fight us–they make changes to the viral genome until the virus gives up and can’t keep attacking anymore.

Some viruses, like HIV and influenza, evade our defenses by mutating themselves. We can keep getting the flu year after year because the virus comes back with just enough changes to its genome that it is unrecognizable to our immune system. The equivalent of a fake mustache and a trench coat is enough of a change to slip past the body’s defenses and make us sick. Again.

APOBECs turn the tables, bombarding the viral genome with more changes than it can handle. Maybe it can still infect and reproduce with a fake mustache and trench coat, but with enough mutations it turns into something that can’t cause illness anymore.

The potential downside is that the mutation attack can become friendly fire, and turn against its own cells, leading to cancer. What the Cornell team learned is that the friendly fire self-mutation attack can create mutations that are passed on to progeny. That means that a defense system meant to disable attacking viruses could also be a force for evolution.

The researchers looked a type of APOBEC specific to primates, called APOBEC3. Because APOBEC3 creates a specific pattern to its mutations, they were able to see thousands of incidences of APOBEC3 in primate genomes, and that activity was over-represented in functional regions.

That means that when APOBEC3 went on a friendly fire frenzy, and attacked a functional region of the primate genome, that change was somehow maintained. Typically, one of three things happens when DNA in a functional region is mutated. First, it could be very, very bad and lead to pretty much immediate death or nonviability of the organism. Those changes are obviously not passed down through the generations. Second, it might make zero difference. Those changes could be passed on, but they tend not to be maintained and conserved in the genome. Last, the change could be advantageous. The presence of many changes by APOBEC3 that have been maintained and passed on through the generations in the primate genome implies that those changes were evolutionarily advantageous.

This really shakes up older theories of how evolution happens. Mutations are supposed to happen at random on a fairly predictable schedule, and species divergence estimates have been based on that assumption.

I reached out to Cornell to ask for more information about the implications of this study, and Postdoctoral Research Associate Aaron Sams explained,

“The typical way of thinking about the timing of divergence is as a ‘molecular clock.’  We think of most mutations as arising individually and randomly over time. If we assume that the process that generates these mutations is essentially random, and we know a rate at which that process generates those random mutations, then we can use the number of mutations that accumulate between two species to estimate the amount of time that has passed since their divergence.”

APOBEC3 is specific to primates, so I asked Aaron if that means primate evolution is different in any way. Like, are primates in some way the influenza among vertebrates? Sams says…maybe.

“That’s a great question, but we don’t really know. It is something that we would like to know though. I am inclined to doubt that this process would lead to faster evolution in primates in general, but it could be possible that APOBECs could drive faster evolution in particular regions of the genome, a single gene or set of genes for instance.
It still isn’t clear to us if the types of mutation clusters that we identified accumulated in bursts, or accumulated more or less gradually. The lead authors of this paper, Yishay Pinto and Orshay Gabay, are working to better understand these types of questions.”
The study was published in Genome Research.

Transitions

First, I want to let you know I did survive the 60 day bikram yoga challenge. It got a bit hairy toward the end because I had a cold for ten days. I toughed out most of the sick days–one class I literally felt so bad I slept the whole class through. I had to take a couple days off to recuperate, so there were a couple of double classes to squeeze in at the end. It was pretty awesome to finish. I felt lucky that I was able to find a 60-day space in my life, somehow, for this to happen. The benefits are kind of intangible. I am slightly better at yoga. I may or may not have added a few months to my life? Hard to say. I did get a free massage and facial at the spa next door and that was really nice.

I’m glad I chose to do it when I did because a family emergency made March Very Complicated. Everything is fine, but it simply would not have worked to do yoga every day. And from that I would say the lesson is whatever you want to do, jump in with both feet and go for it, because there’s really no telling what will happen or change in the future.

Speaking of change! I’m working on transitioning this blog to a more science focused space. I’ve been wanting to do that for quite some time, and as per above realized that there’s no time like the present. Watch this space!