Use scala Type to set type parameter (thru TypeTag?)

I'd like to dynamically insert a type parameter, i.e. List[T], where T can only be found at run-time.

Normally you can create bindings like this if you already have an existing type parameter T (not the case), or during run-time using TypeTags.

The latter sounds like the way to go, but this shifts the question to "how do I get my TypeTag here".

I know how to create a TypeTag using if you have your type T (typeTag[T]), or if you have an instance of your type T (see getTypeTag below).

However, I have neither; what I do have of my type in question is a reflect.runtime.universe.Type. Might it be possible to convert this into a TypeTag so I can dynamically insert my type parameter?

Bonus points if the List can be made dynamic as well.

scala> import scala.reflect.runtime.{universe => ru}

scala> def getTypeTag[T: ru.TypeTag](obj: T) = ru.typeTag[T]

scala> def insertTag[T](tt: ru.TypeTag[T]) = List[T]_

scala> val fn = (a: String) => "foo"
fn: String => String = <function1>

scala> val pars = getTypeTag(fn).tpe.typeArgs.init(0)
pars: reflect.runtime.universe.Type = String

scala> insertTag(pars)
<console>:21: error: type mismatch;
 found   : reflect.runtime.universe.Type
 required: reflect.runtime.universe.TypeTag[?]
       insertTag(pars)
                 ^