DNA runs through this puzzle like sands through an hourglass. There's a pretty nifty representation of a double helix using the black squares, and each long down answer has the genetic letters split in the same way across two words. I like TOOTHANDNAIL the best of them, with the clue for BRANDNAMES (29D: Wilson and Hoover, but not Eisenhower) making it a close second. OLDNAVY has appeared a number of times in the puzzle (with much the same clue), while ISLANDNATION feels arbitrary and GOODNATURE bland.
For all of those long theme answers, it's a very smooth grid. There are a ton of Os in the top and bottom third and weirdly only one in the middle third. All those Os really draw the eye: OOO crossing GOODNATURE, LOON crossing IDOTOO, BOOP near TOOTHANDNAIL. We also had the strange family connection of EVE, ADAM, and ENOS.
Huygens may enjoy the presence of NUDE (41A: Beige shade, right next to the aforementioned first couple, whose lack of clothes were revealed to them) and TITS (3D: Small songbirds). Me, I liked 8D: Speak Persian? (MEOW) and the hidden capital in 13D: Hall of fame (MONTY). A reminder of Jodie Foster as CLARICE Starling is welcome too.
Oh, hey! I didn't even see the revealer until I went through each clue. I'd answered that small section entirely with acrosses. I kind of like it better without the revealer.
Thumbs up, on the whole.