The absence of real morphological complexity in bacteria is plausibly ascribed to the dominant mode of prokaryotic evolution: prokaryotes are streamlined by selection for small genomes and fast replication, quickly losing unnecessary genes, and frequently acquiring new genes from the metagenome, when needed, by lateral gene transfer [ 35, 36].
I personally doubt that selection for replication speed would tend to favour wild-type mitochondria.
Thus, anteriorward serial replication of the mesoderm-derived structures (shell muscles excepted) in the Monoplacophora could be driven by selection for increasing respiratory surface.
This selection might have been based purely on selection for speedy replication; alternatively, the slowed replication might actually represent an average of individual replication-disruption events, each of which is counter-selected independently because genome integrity is selected.
The 95 SNPs selected for replication were genotyped by LGC Genomics (Hoddeson, UK) in 1303 patients from the POSH cohort.
These bacteria possess highly compact genomes and evolve under strong purifying selection suggesting that in these cases, the loss of non-essential genes, mobile elements and intergenic regions is indeed driven by powerful selection for rapid genome replication and minimization of the resources required for growth.
In other words, selection at the between-host level could – in an endemic situation – predominate over selection for faster replication at the within-host level (for examples of conflicting levels of selection see [27], [28]).
For example, selection for fast replication among the cells of multicellular individuals can lead to cancer.
We therefore used a lower threshold for selection of SNPs for replication in an independent study, PPP-Botnia.
Catalytically perfect units of replication evolve quickly by using an evolutionary optimization algorithm that selects sequences for replication rate.
