and Reversed

Well, today's puzzle certainly whooped me. Not only the clues, but the theme. So I got three answers and also a the pun the three are connected, and I still couldn't get the theme. What's the connection?

Riding a bike, eg, for most - secondnature
Everyone knows it - householdname
Annual Oct 24 honoree - unitednations
What the three contain, in a manner of speaking - splicedgenes

So I'm thinking how three three clues can be an example of the theme. And my first thought was that these were famous Genes and their last names were split apart. So for example, there's a famous Gene Secure, and if you splice Secure, you can get SECondnatURE. So that got me staring and staring to no avail. I had to refer to the forum to see what others said. And learned that a more appropriate title would be spliced with genes. See, these are all clues with dna hidden in them. While I like clues like this (another one that comes to mind was a puzzle with words like hotellobby, builttoscale and the theme was hidden operas) this was had a misleading theme name. But a valiant effort nonetheless.

A lot I didn't know in this puzzle. There's some words I know the meaning of but didn't connect with the clues to put them in. Like Assay, Limber, Tempest.

Clues to learn:
Hans Christian Anderson's birth city - Odense
Green-skinned dancing girl in Star Wars - Oola (how am I supposed know this?)
Lincoln's first VP - Hannibal Hamlin
Eden Prairie - Minn. town
Frankie Laine sang Moonlight Gambler
Entre Nous - literally "between us" an adverb to specify information is a secret.
Awn - plant bristle (usually found on grass)
Soporific - inducing sleep, so a soporific deliver is monotone.

Cute Clues:
Horseplay? - polo
Put a new handle on - rename
Org. with a mission - nasa