Evidence of Heritability in Prebiotically Realistic Membrane-Bound Systems

Abstract

The vesicles of short chain amphiphiles have been demonstrated to grow and divide. Here, we explored whether vesicle populations show evidence of heritability. We prepared 1:1 decanoic acid:decylamine vesicles with or without a detergent and in either water or prebiotic soup, a mixture of compounds that might have been present on early Earth. The mixtures were subjected to transfer with dilution, where, after 24 h of incubation (one generation), we transferred 10% of the mix into a 90% volume of a fresh vesicle-containing solution. This was continued for 30 generations. Samples with a history of transfers were compared to no-transfer controls (NTCs), initiated each generation using the same solutions but without 10% of the prior generation. We compared the vesicle size distribution and chemical composition of the transfer samples and NTCs and compared their fluorescence signals in the presence of Nile Red dye. We observe changes in the vesicle size but did not detect differences in the chemical composition. In the samples with detergent and soup, we observed irregular changes in the Nile Red fluorescence, with a tendency for parent and offspring samples to have correlated values, suggestive of heritability. This last result, combined with evidence of temporal autocorrelation across generations, suggests the possibility that vesicles could respond to selection.