Interspecific Gene Flow and Potential Hybrid Breakdown in South Atlantic Sea Turtles.
7 affiliations
- 1Laboratório de Biodiversidade e Evolução Molecular (LBEM), Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
- 2State Museum of Natural History Stuttgart, Stuttgart, Germany.
- 3University of Hohenheim, Stuttgart, Germany.
- 4Center of Excellence for Biodiversity and Integrative Taxonomy (KomBioTa), Stuttgart, Germany.
- 5Leibniz Institute for Zoo and Wildlife Research (IZW), Berlin, Germany.
- 6Berlin Center for Genomics in Biodiversity Research (BeGenDiv), Berlin, Germany.
- 7IN2PAST.BR - National Institute of Science and Technology in Natural and Cultural Heritage, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Abstract
Interspecific hybridisation can play an important evolutionary role, generating new taxa or outbreeding depression, which can also lead to behavioural reproductive isolation through reinforcement. Still, there are few studies investigating how divergence time relates to hybridisation rates and its impact on introgression. Sea turtles are known to hybridise, despite their long divergence times and behavioural, ecological and morphological differences. Several genetic studies have attempted to determine the extent of hybridisation between four of the seven extant sea turtle species (Caretta caretta, Eretmochelys imbricata, Lepidochelys olivacea and Chelonia mydas) in the South Atlantic coast of Brazil, an area known to include nesting and feeding sites for all these species. In this work, we combined new and published genomic data of all four sea turtle species and their hybrids in a detailed population genomics study. Although hybridisation does occur in Brazilian nesting sites between three of the four species, it appears to be limited to first-generation hybrids and few backcrosses, which points to some postzygotic barriers between species and hybrid breakdown. Moreover, our evidence suggests a moderately high level of relatedness among hybrids, indicating a reduced number of independent hybridisation events. Despite this fact, we found evidence of backcrosses involving different species, and an F2 progeny between Ca. caretta x E. imbricata F1 hybrids, which suggests hybrid male fertility. Limited interspecific gene flow appears to be part of the long history of divergence of sea turtles, as low levels of deep time introgression were inferred. In summary, this work contributes important evidence regarding the rate and success of hybridisation at large scales of divergence, and how this seemingly equates to low rates of introgression, pointing to temporal limits to gene flow.
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BibTeX
@article{oliveira2026interspecific,
title = {{Interspecific Gene Flow and Potential Hybrid Breakdown in South Atlantic Sea Turtles.}},
author = {M D Oliveira and R J Pereira and L S Arantes and C J Mazzoni and F R Santos},
journal = {Molecular ecology},
year = {2026},
month = oct,
doi = {10.1111/mec.70607},
url = {https://europepmc.org/article/MED/42920359},
note = {CC BY},
}
RIS
TY - JOUR
TI - Interspecific Gene Flow and Potential Hybrid Breakdown in South Atlantic Sea Turtles.
AU - M D Oliveira
AU - R J Pereira
AU - L S Arantes
AU - C J Mazzoni
AU - F R Santos
PY - 2026
DA - 2026/10/01
JO - Molecular ecology
DO - 10.1111/mec.70607
UR - https://europepmc.org/article/MED/42920359
AB - Interspecific hybridisation can play an important evolutionary role, generating new taxa or outbreeding depression, which can also lead to behavioural reproductive isolation through reinforcement. Still, there are few studies investigating how divergence time relates to hybridisation rates and its impact on introgression. Sea turtles are known to hybridise, despite their long divergence times and behavioural, ecological and morphological differences. Several genetic studies have attempted to determine the extent of hybridisation between four of the seven extant sea turtle species (Caretta caretta, Eretmochelys imbricata, Lepidochelys olivacea and Chelonia mydas) in the South Atlantic coast of Brazil, an area known to include nesting and feeding sites for all these species. In this work, we combined new and published genomic data of all four sea turtle species and their hybrids in a detailed population genomics study. Although hybridisation does occur in Brazilian nesting sites between three of the four species, it appears to be limited to first-generation hybrids and few backcrosses, which points to some postzygotic barriers between species and hybrid breakdown. Moreover, our evidence suggests a moderately high level of relatedness among hybrids, indicating a reduced number of independent hybridisation events. Despite this fact, we found evidence of backcrosses involving different species, and an F2 progeny between Ca. caretta x E. imbricata F1 hybrids, which suggests hybrid male fertility. Limited interspecific gene flow appears to be part of the long history of divergence of sea turtles, as low levels of deep time introgression were inferred. In summary, this work contributes important evidence regarding the rate and success of hybridisation at large scales of divergence, and how this seemingly equates to low rates of introgression, pointing to temporal limits to gene flow.
SN - 0962-1083
SN - 1365-294X
ER -