| dc.creator | Cerón Romero, Mario Alberto | |
| dc.creator | Massey, Steven E. (Consejero) | |
| dc.date | 2015-11-17T20:30:59Z | |
| dc.date | 2015-11-17T20:30:59Z | |
| dc.date | 2015-11-17T20:30:59Z | |
| dc.date.accessioned | 2017-03-17T16:54:47Z | |
| dc.date.available | 2017-03-17T16:54:47Z | |
| dc.identifier | http://hdl.handle.net/10586 /562 | |
| dc.identifier.uri | http://repositorioslatinoamericanos.uchile.cl/handle/2250/647677 | |
| dc.description | Factors such as effective population size (Ne) and proteome size modulate the interaction
of selection, drift, mutation and recombination for guiding the genome evolution.
Prokaryotic genomes are useful for studying these interactions in front of phenomena
such as endosymbiosis. The reduced Ne of endosymbionts causes a more effective drift
than selection and a more accelerated Muller’s ratchet. As prokaryotes have a deletional
bias, the continuous ratchet causes a genome size reduction. Moreover, less effective
proteomic selection leads to tRNA redundancy decay producing higher translational
selection. This study aims to explain differences of proteomic selection among
prokaryotes and their relationship with translational selection. Differences of proteomic
selection were estimated by comparing their GCnonsyn constraint. This study shows that
GCnonsyn should be measured in front of variations of GCsyn, and GCsyn cannot be
used interchangeably with intergenic GCcontent because they have differences due to
acquisition of R-M systems. Non-endosymbionts show a stronger proteomic selection
than endosymbionts due to Muller’s ratchet and reduced Ne. Intracellular bacteria have
stronger proteomic selection than metazoan mitochondria due to small differences of
recombination and/or differences of proteomic constraint. In contrast, chloroplasts have
similar proteomic selection than non-endosymbionts due to homologous recombination;
and their genome size reduction is likely due to migrations of sequences to the nucleus.
The estimates of proteomic selection and translational selection demonstrated that both
factors are related, being metazoan mitochondria the most conclusive evidence of such
relationship. This study demonstrates that GCnosyn vs. GCsyn is an accurate method to
estimate differences of proteomic selection among prokaryotes and that patterns of genome evolution among endosymbionts can be very different due to the complicated
nature of endosymbiosis. | |
| dc.language | en | |
| dc.subject | Effective codons | |
| dc.subject | Fixation index | |
| dc.subject | Mutation rate | |
| dc.subject | Effective population size | |
| dc.subject | GC content | |
| dc.subject | Lateral Gene-Transfer | |
| dc.subject | Genome evolution | |
| dc.subject | Prokaryotic genomes | |
| dc.subject | Endosymbionts | |
| dc.title | Comparing Proteome Selection Pressure Among Prokaryotes and its Effects on Translational Selection | |
| dc.type | Tesis | |
