Barriers to gene flow and ring species formation

Evolution ◽  
2016 ◽  
Vol 71 (2) ◽  
pp. 442-448 ◽  
Author(s):  
Ayana de Brito Martins ◽  
Marcus Aloizio Martinez de Aguiar
Keyword(s):  
Gene Flow ◽  
Species Formation ◽  
Ring Species

scholarly journals A lizard with two tales: what diversification within Sceloporus occidentalis teaches us about species formation

2021 ◽  
Author(s):  
Ricardo Pereira ◽  
Sonal Singhal
Keyword(s):  
Gene Flow ◽  
Genetic Drift ◽  
Charles Darwin ◽  
Molecular Ecology ◽  
Genetic Interactions ◽  
Sceloporus Occidentalis ◽  
Genome Data ◽  
Species Formation ◽  
Ring Species ◽  
Natural Laboratory

In 1859, Charles Darwin proposed that species are not fundamentally different from subspecies or the varieties from which they evolve. A century later, Dobzhansky (1958) suggested that many such lineages are ephemeral and are likely to revert differentiation through introgression (Fig. 1A); only a few evolve complete reproductive isolation and persist in sympatry. In this issue of Molecular Ecology, Bouzid et al. (2021) show how new analytical methods, when applied to genome data, allow us to more precisely determine whether or not species formation follows the paths outlined by Darwin and Dobzhansky (Fig. 1B). The authors study the diversification of the lizard Sceloporus occidentalis, finding a continuum of genetic interactions between the preservation of genetic identity to genetic merger, analogous to what is exemplified by ring species. In doing so, they teach us two tales on species formation: that lineages are fractal byproducts of evolutionary processes such as genetic drift and selection, and that lineages are often ephemeral and do not always progress into species. Studying ephemeral lineages like those in S. occidentalis allows us to capture divergence at its earliest stages, and potentially to determine the factors that allow lineages to remain distinct despite pervasive gene flow. These lineages thus serve as a natural laboratory to address long standing hypotheses on species formation.

scholarly journals Extensive introgression despite Haldane’s rule: insights from grasshopper hybrid zones

2021 ◽  
Author(s):  
Linda Hagberg ◽  
Enrique Celemin ◽  
Iker Irisarri ◽  
Oliver Hawlitschek ◽  
J L Bella ◽  
...  
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Male Sterility ◽  
Secondary Contact ◽  
Hybrid Zones ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Haldane’S Rule ◽  
Haldane's Rule ◽  
Species Formation

Although the process of species formation is notoriously idiosyncratic, the observation of pervasive patterns of reproductive isolation across species pairs suggests that generalities, or “rules”, underlie species formation in all animals. Haldane’s rule states that whenever a sex is absent, rare or sterile in a cross between two taxa, that sex is usually the heterogametic sex. Yet, understanding how Haldane’s rule first evolves and whether it is associated to genome wide barriers to gene flow remains a challenging task because this rule is usually studied in highly divergent taxa that no longer hybridize in nature. Here, we address these questions using the meadow grasshopper Pseudochorthippus parallelus where populations that readily hybridize in two natural hybrid zones show hybrid male sterility in laboratorial crosses. Using mitochondrial data, we infer that such populations have diverged some 100,000 years ago, surviving multiple glacial periods in isolated Pleistocenic refugia. Nuclear data shows that secondary contact has led to extensive introgression throughout the species range, including between populations showing hybrid male sterility. We find repeatable patterns of genomic differentiation across the two hybrid zones, yet such patterns are consistent with shared genomic constraints across taxa rather than their role in reproductive isolation. Together, our results suggest that Haldane’s rule can evolve relatively quickly within species, particularly when associated to strong demographic changes. At such early stages of species formation, hybrid male sterility still permits extensive gene flow, allowing future studies to identify genomic regions associated with reproductive barriers.

scholarly journals Ring species as demonstrations of the continuum of species formation

2015 ◽  
Vol 24 (21) ◽  
pp. 5312-5314 ◽  
Author(s):  
Ricardo J. Pereira ◽  
David B. Wake
Keyword(s):  
Species Formation ◽  
Ring Species ◽  
The Continuum

scholarly journals A Spatial Framework for Understanding Population Structure and Admixture.

2015 ◽  
Author(s):  
Gideon Bradburd ◽  
Peter L. Ralph ◽  
Graham Coop
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Human Populations ◽  
Geographic Proximity ◽  
Genetic Covariance ◽  
Geographic Patterns ◽  
Genome Wide ◽  
Limited Dispersal ◽  
Phylloscopus Trochiloides ◽  
Ring Species

Geographic patterns of genetic variation within modern populations, produced by complex histories of migration, can be difficult to infer and visually summarize. A general consequence of geographically limited dispersal is that samples from nearby locations tend to be more closely related than samples from distant locations, and so genetic covariance often recapitulates geographic proximity. We use genome-wide polymorphism data to build ``geogenetic maps,'' which, when applied to stationary populations, produces a map of the geographic positions of the populations, but with distances distorted to reflect historical rates of gene flow. In the underlying model, allele frequency covariance is a decreasing function of geogenetic distance, and nonlocal gene flow such as admixture can be identified as anomalously strong covariance over long distances. This admixture is explicitly co-estimated and depicted as arrows, from the source of admixture to the recipient, on the geogenetic map. We demonstrate the utility of this method on a circum-Tibetan sampling of the greenish warbler (Phylloscopus trochiloides), in which we find evidence for gene flow between the adjacent, terminal populations of the ring species. We also analyze a global sampling of human populations, for which we largely recover the geography of the sampling, with support for significant histories of admixture in many samples. This new tool for understanding and visualizing patterns of population structure is implemented in a Bayesian framework in the program SpaceMix.

scholarly journals Evidence for ephemeral ring species formation during the diversification history of western fence lizards ( Sceloporus occidentalis )

2021 ◽  
Author(s):  
Nassima M. Bouzid ◽  
James W. Archie ◽  
Roger A. Anderson ◽  
Jared A. Grummer ◽  
Adam D. Leaché
Keyword(s):  
Sceloporus Occidentalis ◽  
Species Formation ◽  
History Of ◽  
Ring Species

scholarly journals The evolution of reproductive isolation in Daphnia

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Tiffany A. Chin ◽  
Carla E. Cáceres ◽  
Melania E. Cristescu
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Daphnia Pulex ◽  
Early Stages ◽  
Relative Contribution ◽  
Prezygotic Barriers ◽  
Ecological Barriers ◽  
Species Formation ◽  
Complex Process ◽  
Postzygotic Reproductive Isolation

Abstract Background The process by which populations evolve to become new species involves the emergence of various reproductive isolating barriers (RIB). Despite major advancements in understanding this complex process, very little is known about the order in which RIBs evolve or their relative contribution to the total restriction of gene flow during various stages of speciation. This is mainly due to the difficulties of studying reproductive isolation during the early stages of species formation. This study examines ecological and non-ecological RIB within and between Daphnia pulex and Daphnia pulicaria, two recently diverged species that inhabit distinct habitats and exhibit an unusual level of intraspecific genetic subdivision. Results We find that while ecological prezygotic barriers are close to completion, none of the non-ecological barriers can restrict gene flow between D. pulex and D. pulicaria completely when acting alone. Surprisingly, we also identified high levels of postzygotic reproductive isolation in ‘conspecific’ interpopulation crosses of D. pulex. Conclusions While the ecological prezygotic barriers are prevalent during the mature stages of speciation, non-ecological barriers likely dominated the early stages of speciation. This finding indicates the importance of studying the very early stages of speciation and suggests the contribution of postzygotic isolation in initiating the process of speciation.

Great Wall blocks gene flow

Nature ◽  
2003 ◽  
Author(s):  
HelenR. Pilcher
Keyword(s):  
Gene Flow ◽  
Great Wall

Differentiation and Interrelations of Two Representatives of Laudakia stellio Complex (Reptilia: Agamidae) in Israel

2011 ◽  
Vol 4 (2) ◽  
pp. 102-114 ◽  
Author(s):  
Evgenyi N. Panov ◽  
Larissa Yu. Zykova
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Habitat Preference ◽  
Additional Data ◽  
Near East ◽  
Field Studies ◽  
Subspecies Level ◽  
Limited Gene Flow ◽  
Study Sites ◽  
And Behavior

Field studies were conducted in Central Negev within the breeding range of Laudakia stellio brachydactyla and in NE Israel (Qyriat Shemona) in the range of an unnamed form (tentatively “Near-East Rock Agama”), during March – May 1996. Additional data have been collected in Jerusalem at a distance of ca. 110 km from the first and about 170 km from the second study sites. A total of 63 individuals were caught and examined. The animals were marked and their subsequent movements were followed. Social and signal behavior of both forms were described and compared. Lizards from Negev and Qyriat Shemona differ from each other sharply in external morphology, habitat preference, population structure, and behavior. The differences obviously exceed the subspecies level. At the same time, the lizards from Jerusalem tend to be intermediate morphologically between those from both above-named localities, which permits admitting the existence of a limited gene flow between lizard populations of Negev and northern Israel. The lizards from NE Israel apparently do not belong to the nominate subspecies of L. stellio and should be regarded as one more subspecies within the species.

Sign in / Sign up

Export Citation Format

Share Document