Parallel adaptation prompted core-periphery divergence of Ammopiptanthus mongolicus

Area of Science:

• Ecology
• Evolutionary Biology
• Genetics

Background:

• Range expansion necessitates peripheral populations adapting to new environmental conditions.
• Desert plants face limitations to expansion due to harsh conditions like drought and temperature extremes.
• Ammopiptanthus mongolicus, a desert shrub, shows wide distribution but potential genetic constraints.

Purpose of the Study:

• Investigate core-periphery environmental and genetic differences in Ammopiptanthus mongolicus.
• Identify environmental factors limiting desert plant range expansion.
• Determine adaptive peripheral populations and their genetic-environmental associations.

Main Methods:

• Comparison of genome-wide polymorphisms between core and peripheral populations.
• Analysis of environmental factors across different populations.
• Identification of genetic-environmental association patterns.

Main Results:

• Four adaptive peripheral populations showed similar genetic-environmental patterns.
• High elevation, summer drought, and winter cold converged these populations.
• Peripheral populations adapted to warmer, more humid conditions, diverging from the core population's legacy.

Conclusions:

• Altitudinal adaptation is key for breaching niche boundaries and enabling range expansion.
• Relaxation of environmental constraints (drought, cold) facilitates genetic divergence.
• Parallel adaptation in peripheral populations results from pleiotropic selection and integration of standing genetic variation.