RT Journal Article
SR Electronic
T1 Uniparental Inheritance Promotes Adaptive Evolution in Cytoplasmic Genomes
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 059089
DO 10.1101/059089
A1 Joshuaa R. Christie
A1 Madeleine Beekmanc
YR 2016
UL http://biorxiv.org/content/early/2016/06/15/059089.abstract
AB Eukaryotes carry numerous asexual cytoplasmic genomes (mitochondria and chloroplasts). Lacking recombination, asexual genomes suffer from impaired adaptive evolution. Yet, empirical evidence suggests that cytoplasmic genomes do not suffer this limitation of asexual reproduction. Here we use computational models to show that the unique biology of cytoplasmic genomes—specifically their organization into host cells and their uniparental inheritance–enable them to undergo adaptive evolution more effectively than comparable free-living asexual genomes. Uniparental inheritance decreases competition between different beneficial substitutions (clonal interference), reduces genetic hitchhiking of deleterious substitutions during selective sweeps, and promotes adaptive evolution by increasing the level of beneficial substitutions relative to deleterious substitutions. When cytoplasmic genome inheritance is biparental, a tight transmission bottleneck aids adaptive evolution. Nevertheless, adaptive evolution is always more efficient when inheritance is uniparental. Our findings help explain empirical observations that cytoplasmic genomes—despite their asexual mode of reproduction–can readily undergo adaptive evolution.