Comparative analysis of archaeal, bacterial, and eukaryotic genomes
indicates the occurrence of horizontal gene transfer (HGT) in many genomes. Although
widely studied in prokaryotic systems, eukaryotes, which were thought to evolve
principally through reproduction and mutation (vertical gene transfer), also acquire
novel genes and pathways through the acquisition of sequences from distantly related
species. HGT is a notable phenomenon that allows the sharing of genetic information
among members of most or all kingdoms. HGT leads to extremely dynamic genomes,
which have the potential to effectively change the type and presence of secondary
metabolites in an organism. HGT is documented in fungi, bacteria, animals, and
plants - when viral mechanisms are included, all organisms likely are subject to HGT.
The quantities of genetic material that are horizontally transferred range from small
gene fragments to groups of genes, including whole operons that encode complex
biochemical pathways. Examples of HGT that contribute to novel or expanded ranges
of secondary metabolite products include filamentous and unicellular fungi,
actinomycetes and other bacteria, and plants. In this chapter we will discuss several
examples of secondary metabolite production that occur as a consequence of HGT, the
study of natural products acquired through HGT processes and the ramifications of
HGT for biosynthesis and exploitation of natural products that arise from horizontallytransferred
pathways. We have focused primarily on the literature published from 2000
to 2015.
Keywords: Bioinformatics, Eukaryotes, Evolution, Horizontal gene transfer,
Lateral gene transfer, Natural products, Prokaryotes, Secondary metabolites.
