Repeated global adaptation across plant species

Area of Science:

• Evolutionary biology
• Genomics
• Plant science

Background:

• Global adaptation involves species-wide selection towards a common optimum, often driven by hard selective sweeps.
• Selective sweeps leave detectable genomic traces, but comparative studies on genes involved in global adaptation are limited.
• Previous research suggests repeated genetic bases for local adaptation across species.

Purpose of the Study:

• To investigate whether specific genes play a significant role in driving global adaptation across diverse plant species.
• To identify gene families with evidence of repeated global selective sweeps in plants.
• To compare the characteristics of genes involved in global adaptation with those involved in local adaptation.

Main Methods:

• Genome-wide scans were performed on 17 plant species to detect signals of repeated global selective sweeps.
• Population genomic methods were used to identify evolutionary traces of adaptation.
• Analysis focused on identifying gene families and their properties, such as pleiotropy and gene duplication.

Main Results:

• Several gene families showed strong evidence of repeated positive selection across the 17 plant species.
• These gene families were enriched for reduced pleiotropy, aligning with evolutionary models.
• Genes with repeated sweeps exhibited higher levels of gene duplication compared to other genes.
• Findings contrasted with studies on local adaptation, which indicated increased pleiotropy.

Conclusions:

• Specific gene families appear to be recurrently involved in global adaptation across distantly related plant species.
• Reduced pleiotropy and increased gene duplication are characteristic of genes driving global adaptation.
• These results offer insights into the genetic mechanisms underlying large-scale evolutionary change in plants.