Evolutionary history and genetic parallelism affect correlated responses to evolution.

Area of Science:

• Evolutionary biology
• Microbial evolution
• Genomics

Background:

• Understanding the relationship between genetic changes and observable traits is crucial for evolutionary studies.
• Replicate populations allow for the investigation of parallel evolutionary trajectories under controlled conditions.

Purpose of the Study:

• To investigate the link between genomic alterations and phenotypic adaptations in Escherichia coli populations.
• To identify patterns of genetic and phenotypic parallelism across different environments.

Main Methods:

• Resequencing of evolved Escherichia coli genomes after 1000 generations.
• Characterization of evolved clones in their native and alternative environments.
• Analysis of genetic mutations at the codon, domain, and gene levels.

Main Results:

• Parallel genetic changes were observed in genes encoding transcription regulators, both within and between environments.
• Evolved clones exhibited parallel phenotypic changes in their respective and alternative environments.
• Phenotypic parallelism was higher in clones from the same environment, irrespective of genetic parallelism.
• Clones from different environments showed greater correlated responses when sharing mutated genes.

Conclusions:

• Environmental changes can lead to predictable evolutionary outcomes.
• Similar ecological performance can result from shared genetic mutations or parallel selective pressures.
• This study highlights the interplay between genotype and phenotype in microbial adaptation.