Learn Finnish: Hakijalta edellytetään kokemusta lahjakkuuden ohella. - Experience is required from the applicant alongside talent.

The word lahjakkuuden is governed by the postposition ohella (alongside / in addition to). As with most postpositions in Finnish, ohella requires the word it modifies to be in the genitive case.

Why do we use the ablative case (hakijalta) for the applicant instead of another 'from' case like the elative?

The verb edellyttää (to require / to presuppose) has a specific rection: the person from whom something is required must be in the ablative case (-lta/-ltä). You can think of it as expecting a certain quality to be presented 'from the surface' of them.

In a passive sentence like this (edellytetään), shouldn't the object be in the nominative case instead of the partitive (kokemusta)?

You are right to remember that the total object of a passive verb often takes the nominative case. However, kokemus (experience) is an uncountable, abstract concept here. Uncountable mass objects always remain in the partitive case, even in passive sentences. Furthermore, the verb edellyttää usually requires a partitive object anyway.

Let's break down the word lahjakkuuden. How is it formed from the basic word for 'gift'?