Nucleic acid segregation and compartmentalization were likely essential functions that primitive compartment systems resolved during evolution. Recently,
polyester microdroplets generated from
dehydration synthesis of various α-
hydroxy acids (αHA) were suggested as potential primitive compartments. Some of these droplets can differentially segregate and compartmentalize organic
dyes,
proteins, and
nucleic acids. However, the previously studied
polyester microdroplets included limited αHA chemical diversity, which may not reflect the chemical diversity available in the primitive Earth environment. Here, we increased the chemical diversity of
polyester microdroplet systems by combinatorially adding an αHA monomer with a basic side chain,
4-amino-2-hydroxybutyric acid (4a2h), which was incorporated with different ratios of other αHAs containing uncharged side chains to form combinatorial heteropolyesters via
dehydration synthesis. Incorporation of 4a2h in the
polymers resulted in the assembly of some
polyester microdroplets able to segregate fluorescent
RNA or potentially acquire intrinsic fluorescent character, suggesting that minor modifications of
polyester composition can significantly impact the functional properties of primitive compartments. This study suggests one process by which primitive chemical systems can increase diversity of compartment "phenotype" through simple modifications in their chemical composition.