Utilization of genomic retrotransposons as cladistic markers

Genomic retrotransposons are major genomic components in most eukaryotic organisms. Their abundance in the genome is generally correlated with genome size. These elements spread throughout the genome by a process termed retro-transposition consisting of transcription, reverse transcription and reinsertion of the copied element into a new genomic location. The target sites are relatively unspecific and independent, thus, integration of the same element into specific site in different taxa is negligible over evolutionary time scales. However, utilization of retrotransposons as cladistic molecular markers represents a particularly interesting complement to other molecular and morphological data. These markers can differentiate between ancestral and derived character state at a respective locus. Retrotransposon content of a given species is strongly influenced by the host evolutionary history, with periods of rapid turnover of retrotransposons sequences. Thus, retrotransposon integration markers are an ideal tool for determining the common ancestry of taxa by a shared derived transpositional event.