TY - JOUR

T1 - Hybridization boosts dispersal of two contrasted ecotypes in a grass species

AU - Curran, Emma V.

AU - Scott, Matilda S.

AU - Olofsson, Jill K.

AU - Nyirenda, Florence

AU - Sotelo, Graciela

AU - Bianconi, Matheus E.

AU - Manzi, Sophie

AU - Besnard, Guillaume

AU - Pereira, Lara

AU - Christin, Pascal-Antoine

N1 - Publisher Copyright: © 2022 The Authors.

PY - 2022

Y1 - 2022

N2 - Genetic exchanges between closely related groups of organisms with different adaptations have well-documented beneficial and detrimental consequences. In plants, pollen-mediated exchanges affect the sorting of alleles across physical landscapes and influence rates of hybridization. How these dynamics affect the emergence and spread of novel phenotypes remains only partially understood. Here, we use phylogenomics and population genomics to retrace the origin and spread of two geographically overlapping ecotypes of the African grass Alloteropsis angusta. In addition to an ecotype inhabiting wetlands, we report the existence of a previously undescribed ecotype inhabiting Miombo woodlands and grasslands. The two ecotypes are consistently associated with different nuclear groups, which represent an advanced stage of divergence with secondary low-level gene flow. However, the seed-transported chloroplast genomes are consistently shared by distinct ecotypes inhabiting the same region. These patterns suggest that the nuclear genome of one ecotype can enter the seeds of the other via occasional pollen movements with sorting of nuclear groups in subsequent generations. The contrasting ecotypes of A. angusta can thus use each other as a gateway to new locations across a large part of Africa, showing that hybridization can facilitate the geographical dispersal of distinct ecotypes of the same grass species.

AB - Genetic exchanges between closely related groups of organisms with different adaptations have well-documented beneficial and detrimental consequences. In plants, pollen-mediated exchanges affect the sorting of alleles across physical landscapes and influence rates of hybridization. How these dynamics affect the emergence and spread of novel phenotypes remains only partially understood. Here, we use phylogenomics and population genomics to retrace the origin and spread of two geographically overlapping ecotypes of the African grass Alloteropsis angusta. In addition to an ecotype inhabiting wetlands, we report the existence of a previously undescribed ecotype inhabiting Miombo woodlands and grasslands. The two ecotypes are consistently associated with different nuclear groups, which represent an advanced stage of divergence with secondary low-level gene flow. However, the seed-transported chloroplast genomes are consistently shared by distinct ecotypes inhabiting the same region. These patterns suggest that the nuclear genome of one ecotype can enter the seeds of the other via occasional pollen movements with sorting of nuclear groups in subsequent generations. The contrasting ecotypes of A. angusta can thus use each other as a gateway to new locations across a large part of Africa, showing that hybridization can facilitate the geographical dispersal of distinct ecotypes of the same grass species.

KW - dispersal

KW - ecology

KW - gene flow

KW - growth strategies

KW - hybridization

KW - Poaceae

U2 - 10.1098/rspb.2021.2491

DO - 10.1098/rspb.2021.2491

M3 - Journal article

C2 - 35078363

AN - SCOPUS:85123905471

VL - 289

JO - Philosophical Transactions of the Royal Society B: Biological Sciences

JF - Philosophical Transactions of the Royal Society B: Biological Sciences

SN - 0962-8436

IS - 1967

M1 - 20212491

ER -