Stephen Jay Gould, veja o que acontece quando se toca novamente a fita da evolução

segunda-feira, fevereiro 26, 2018

Journal of Molecular Evolution

March 2017, Volume 84, Issue 2–3, pp 69–84 | Cite as

Experimental Evolution of Escherichia coli Harboring an Ancient Translation Protein


Authors and affiliations

Betül Kacar Xueliang Ge Suparna Sanyal Eric A. Gaucher

Open Access Original Article

First Online: 23 February 2017 


The ability to design synthetic genes and engineer biological systems at the genome scale opens new means by which to characterize phenotypic states and the responses of biological systems to perturbations. One emerging method involves inserting artificial genes into bacterial genomes and examining how the genome and its new genes adapt to each other. Here we report the development and implementation of a modified approach to this method, in which phylogenetically inferred genes are inserted into a microbial genome, and laboratory evolution is then used to examine the adaptive potential of the resulting hybrid genome. Specifically, we engineered an approximately 700-million-year-old inferred ancestral variant of tufB, an essential gene encoding elongation factor Tu, and inserted it in a modern Escherichia coli genome in place of the native tufB gene. While the ancient homolog was not lethal to the cell, it did cause a twofold decrease in organismal fitness, mainly due to reduced protein dosage. We subsequently evolved replicate hybrid bacterial populations for 2000 generations in the laboratory and examined the adaptive response via fitness assays, whole genome sequencing, proteomics, and biochemical assays. Hybrid lineages exhibit a general adaptive strategy in which the fitness cost of the ancient gene was ameliorated in part by upregulation of protein production. Our results suggest that an ancient–modern recombinant method may pave the way for the synthesis of organisms that exhibit ancient phenotypes, and that laboratory evolution of these organisms may prove useful in elucidating insights into historical adaptive processes.


Ancient Gene Laboratory Evolution Minimal Glucose Medium tufA Gene Organismal Fitness 

FREE PDF GRATIS: Journal of Molecular Evolution



Como que alguém atrasa o relógio pela inserção de um gene de 700 milhões de anos no genoma do E. coli? Este gene antigo não é apenas uma sequência gerada por um modelo coalescente de genes modernos de volta a uma hipotética sequência antiga? Se foi assim na pesquisa, eles realmente não sabem como que um gene parecia há 700 milhões de anos. Certo?