Demographic and spatially explicit landscape genomic analyses in a tropical oak reveal the impacts of late Quaternary climate change on Andean montane forests

100%

ORIGINAL ARTICLE

Funding information

Abstract

The tropical Andes are one of the most important biodiversity hotspots on Earth, yet our understanding of how their biotas have responded to Quaternary climatic oscillations is extraordinarily limited and the alternative models proposed to explain their demographic dynamics have been seldom formally evaluated. Here, we test the hypothesis that the interplay between the spatial configuration of geographical barriers to dispersal and elevational displacements driven by Quaternary cooling-warming cycles has shaped the demographic trajectories of montane oak forests from the Colombian Andes. Specifically, we integrate genomic data and environmental niche modelling at fine temporal resolution to test competing spatially explicit demographic and coalescent models, including scenarios considering (i) isotropic gene flow through the landscape, (ii) the hypothetical impact of contemporary barriers to dispersal, and (iii) distributional shifts of montane oak forests from the Last Glacial Maximum to the present. Although our data revealed a marked genetic fragmentation of montane oak forests, statistical support for isolation-with-migration models indicates that geographically separated populations from the different Andean Cordilleras regularly exchange gene flow. Accordingly, spatiotemporally explicit demographic analyses supported a model of flickering connectivity, with scenarios considering isotropic gene flow or currently unsuitable habitats as persistent barriers to dispersal providing a comparatively worse fit to empirical genomic data. Overall, these results emphasize the role of landscape heterogeneity on shaping spatial patterns of genomic variation in montane oak forests, rejecting the hypothesis of genetic continuity and supporting a significant impact of Quaternary climatic oscillations on their demographic trajectories.

One INTRODUCTION |

Two MATERIALS AND METHODS

Two point two. Genetic structure

Two point three. Environmental niche modelling

Two point four. Testing alternative models of population divergence

Variant positions

Two point five. Historical changes in effective population size

Two point six. Testing alternative spatially explicit demographic models

Three RESULTS

Three point one

Three point two Genetic structure

Three point three. Environmental niche modelling

Three point four. Testing alternative models of population divergence

Three point five. Historical changes in effective population size

Three point six. Testing alternative demographic models

Four. DISCUSSION

Four point one. Distributional and demographic trajectories during the Quaternary

Four point two | Genetic fragmentation with limited gene flow

Four point three. Insights from spatially explicit model testing

Five. CONCLUSIONS

AUTHOR CONTRIBUTIONS

DATA AVAILABILITY STATEMENT

SUPPORTING INFORMATION

Overview

The study explores the influence of Quaternary climatic oscillations on the genetic connectivity and demographic trajectories of montane oak (Quercus humboldtii) populations across different Andean Cordilleras. By using genomic data, the research challenges existing models and highlights significant impacts of historical climate change on species distribution and genetic structure.

Key Points

1The study analyzes genetic fragmentation in montane oak forests due to climate change
2It integrates genomic data with environmental niche modeling to assess demographic history
3Findings support a significant impact of Quaternary climatic oscillations on oak populations
4The research rejects the hypothesis of genetic continuity among Andean oak populations
5Results emphasize the role of landscape heterogeneity in shaping genomic variation.

Details

Authors: Joaquín Ortego, Josep Maria Espelta, Dolors Armenteras, María Claudia Diez, Alberto Munoz, Raúl Bonal
Category: Biology and Natural Sciences

PDF
Preserved topography, lateralization, selectivity, and functional connectivity of the language network in older brains
This study investigates the structural and functional changes in the language network of older adults compared to younger individuals using precision fMRI techniques. It focuses on how these changes affect language processing and executive functions in relation to healthy aging.
PDF
Evolutionary associations among pollen scopa structure, floral breadth and eusociality in Halictidae (Hymenoptera: Apoidea)
This paper explores the evolutionary relationships between pollen scopa structure, floral breadth, and eusociality in Halictidae bees through a comparative analysis of 207 species. The research aims to uncover the ecological and morphological factors influencing social behavior among these bees.
PDF
On the Origin of Mitosing Cells
This paper presents a theory on the origin of eukaryotic cells, proposing that certain organelles, like mitochondria and plastids, originated from free-living prokaryotic cells through a series of endosymbiotic events.
PDF
Architects of Order: The History & Evolution of Biological Taxonomy
This document explores the history and evolution of biological taxonomy, detailing key figures and their contributions to the classification of life forms from ancient times to the pre-Linnaean period.
PDF
Novel molecular requirements for CRISPR RNA-guided transposition
This study investigates the molecular requirements for CRISPR RNA-guided transposition, revealing novel sequence determinants and interactions necessary for DNA integration by CRISPR-associated transposases (CASTs).