October 14, 2016 at 03:49AM

Today I Learned: 1) I like persimmons! I'm not sure if I'd ever actually had a persimmon before, but today I had one pretty much fresh off a tree, and it was pretty darned good, for a fruit. I'd describe the taste as kind of a mellow, sweet, orange/mango flavor. 2) There are parasitic transposable elements. I mean, all transposable elements are parasitic on the host genome*. There are, however, also transposable elements that have lost their protein-coding regions. They aren't actually fully functional without *another* transposon around to snip them out and move them from place to place. There are some really clever adaptations transposons have evolved to combat parasitic transposable elements, including a whole class of RNA transposons that get transcribed, leave the nucleus, produce a virion-like coat from a protein monomer, reverse-transcribe themselves, produce and attach an integrase to themselves, and move back to the nucleus for insertion. * this is contentious -- some scientists, most notably those from the ENCODE project, think that transposons are kept around as drivers of genetic variation. However, today I learned that the wider molecular evolution community suspects that this is rubbish, and that transposons are truly junk DNA, in the sense that they do not contribute to host fitness. 3) Apparently what we call "transgenderedness" today was relatively common in Native American societies. Of course, any time someone talks about "Native American societies", they're talking about a huge swath of cultures, some separated by centuries or millennia of divergence, so keep in mind that everything in this particular TIL is a MASSIVE generalization, BUT! The point is that many, many Native American societies had between three and five standard gender concepts. Typcially these were roughly equivalent to one or more of "male", "female", "male in female body", "female in male body", and "male and female". The non-("male" or "female") genders (referred to as "two-spirits" in modern parlance) were considered anywhere from perfectly normal to special and honored. Interesting how different other cultures' views of gender can be from our own... yet also interesting how ultimately circumscribed those gender views are. It all really boils down to variations on "male" and "female" -- even accounting for cultures quite different from ours, the human race hasn't explored the space of possible genders very thoroughly.