What sequence elements could be looked for within the inserted sequence that would help place it in one of the three families?

DNA transposons, viral-like transposable elements, and non-LTR retrotransposons

Explanation:

Transposable Elements (TEs) are genetic mobile elements that can change its position within a genome, thereby producing mutations at the genomic sites where they are inserted. According to their composition and structure, TEs can be divided into three main types: DNA transposons, viral-like transposable elements, and non-long terminal repeat (non-LTR) retrotransposons (also known as polyA retrotransposons). In the first place, DNA transposons are composed of conserved inverted repeat sequences at both ends of the element which are surrounded by target site duplications (TSDs). Moreover, viral-like TEs contain LTRs and they encode reverse transcriptase enzymes. Finally, non-LTR retrotransposons contain a poly(A) tail at the 3′ end, but they don't have inverted repeats.