scholarly journals Formation of a recent hybrid zone offers insight into the geographic puzzle and maintenance of species boundaries in musk turtles

2019 ◽  
Vol 28 (4) ◽  
pp. 761-771 ◽  
Author(s):  
Peter A. Scott ◽  
Travis C. Glenn ◽  
Leslie J. Rissler
Keyword(s):  
Hybrid Zone ◽  
Species Boundaries ◽  
Insight Into

scholarly journals The role of hybridization during ecological divergence of southwestern white pine (Pinus strobiformis) and limber pine (P. flexilis)

2017 ◽  
Author(s):  
Mitra Menon ◽  
Justin C. Bagley ◽  
Christopher Friedline ◽  
Amy V. Whipple ◽  
Anna W. Schoettle ◽  
...  
Keyword(s):  
Gene Flow ◽  
Hybrid Zone ◽  
Ecological Niche Modeling ◽  
Life History Strategies ◽  
Species Boundaries ◽  
Disruptive Selection ◽  
Hybrid Index ◽  
Extrinsic Factors ◽  
Intrinsic Factors ◽  
Demographic Modeling

AbstractInteractions between extrinsic factors, such as disruptive selection, and intrinsic factors, such as genetic incompatibilities among loci, can contribute to the maintenance of species boundaries. The relative roles of these factors in the establishment of reproductive isolation can be examined using species pairs characterized by gene flow throughout their divergence history. We investigated the process of speciation and the maintenance of species boundaries between Pinus strobiformis and P.flexilis. Utilizing ecological niche modeling, demographic modeling, and genomic cline analyses, we illustrated a history of divergence with continuous gene flow between these species. We found an abundance of advanced generation hybrids and a lack of loci exhibiting large allele frequency differences across the hybrid zone. Additionally, we found evidence for climate-associated variation in the hybrid index and niche divergence between parental species and the hybrid zone. Our results are consistent with extrinsic factors, such as climate, being an important isolating mechanism for these species. A buildup of intrinsic incompatibilities and of co-adapted gene complexes is also apparent in our results, although these appear to be in the earliest stages of development. This supports previous work in coniferous species demonstrating the importance of extrinsic factors in creating and enforcing species boundaries. Overall, we lend support to the hypothesis that varying strengths and directions of selection pressures across the long lifespans of conifers, in combination with their life history strategies, delay the evolution of strong intrinsic incompatibilities.

scholarly journals Differential introgression and the maintenance of species boundaries in an advanced generation avian hybrid zone

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Jennifer Walsh ◽  
W. Gregory Shriver ◽  
Brian J. Olsen ◽  
Adrienne I. Kovach
Keyword(s):  
Hybrid Zone ◽  
Species Boundaries ◽  
Advanced Generation

scholarly journals Phylogeography of the Cran’s bully Gobiomorphus basalis (Gobiiformes: Eleotridae) and an analysis of species boundaries within the New Zealand radiation of Gobiomorphus

2020 ◽  
Vol 130 (2) ◽  
pp. 365-381
Author(s):  
James J Shelley ◽  
Bruno O David ◽  
Christine E Thacker ◽  
Andy S Hicks ◽  
Matt G Jarvis ◽  
...  
Keyword(s):  
New Zealand ◽  
Taupo Volcanic Zone ◽  
Species Boundaries ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
The North ◽  
Mitochondrial Data ◽  
History Of ◽  
North And South ◽  
Insight Into

Abstract New Zealand has a complex recent history of climatic and tectonic change that has left variable signatures in the geographic distribution and genetic structure of the region’s flora and fauna. To identify concordant patterns, a broad range of taxa must be examined and compared. In New Zealand’s North Island, a consensus is forming as to the dominant biogeographic barriers in the region although obligate freshwater taxa have not been considered in this framework. We use single-nucleotide polymorphisms to investigate phylogeography in the widespread obligate freshwater fish Gobiomorphus basalis on the North Island. Phylogeographic patterns within G. basalis reveal biogeographic disjunctions that are in some ways consistent and in other ways at odds with established patterns, providing insight into the processes that have shaped the islands’ biogeography. We also use phylogeography to delineate species boundaries within the entire New Zealand radiation of Gobiomorphus and find that it contains several morphologically cryptic species. We resolve two clades within G. basalis that correspond to areas north and south of the Taupo Volcanic Zone. We confirm the distinctiveness of Gobiomorphus alpinus relative to Gobiomorphus cotidianus, as well as the presence of two lineages within Gobiomorphus breviceps that were previously identified based on mitochondrial data.

scholarly journals Low fertility of wild hybrid male flycatchers despite recent divergence

2013 ◽  
Vol 9 (3) ◽  
pp. 20130169 ◽  
Author(s):  
Murielle Ålund ◽  
Simone Immler ◽  
Amber M. Rice ◽  
Anna Qvarnström
Keyword(s):  
Hybrid Zone ◽  
Parental Species ◽  
Low Fertility ◽  
Species Boundaries ◽  
Postzygotic Isolation ◽  
Hybrid Male ◽  
Hybrid Fitness ◽  
Extra Pair Paternity ◽  
Wild Hybrid ◽  
Sperm Traits

Postzygotic isolation may be important for maintaining species boundaries, particularly when premating barriers are incomplete. Little is known about the course of events leading from minor environmental mismatches affecting hybrid fitness to severe genetic incompatibilities causing sterility or inviability. We investigated whether reduced reproductive success of hybrid males was caused by suboptimal sperm traits or by more severe genetic incompatibilities in a hybrid zone of pied ( Ficedula hypoleuca ) and collared flycatchers ( F. albicollis ) on the island of Öland, Sweden. About 4 per cent hybridization is observed in this population and all female hybrids are sterile. We found no sperm in the ejaculates of most sampled hybrid males, and sperm with abnormal morphology in two hybrids. Furthermore, none of the hybrids sired any offspring because of high levels of hatching failure and extra-pair paternity in their nests. These results from a natural hybrid zone suggest that the spermatogenesis of hybrid males may become disrupted despite little genetic divergence between the parental species.

scholarly journals Wolbachiaco-infection in a hybrid zone: discovery of horizontal gene transfers from twoWolbachiasupergroups into an animal genome

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1479 ◽  
Author(s):  
Lisa J. Funkhouser-Jones ◽  
Stephanie R. Sehnert ◽  
Paloma Martínez-Rodríguez ◽  
Raquel Toribio-Fernández ◽  
Miguel Pita ◽  
...  
Keyword(s):  
Genome Sequencing ◽  
Hybrid Zone ◽  
Horizontal Transfer ◽  
Nuclear Genome ◽  
Valuable Insight ◽  
Hybrid Zones ◽  
Natural Hybrid ◽  
Microbial Symbionts ◽  
Insight Into

Hybrid zones and the consequences of hybridization have contributed greatly to our understanding of evolutionary processes. Hybrid zones also provide valuable insight into the dynamics of symbiosis since each subspecies or species brings its unique microbial symbionts, including germline bacteria such asWolbachia, to the hybrid zone. Here, we investigate a natural hybrid zone of two subspecies of the meadow grasshopperChorthippus parallelusin the Pyrenees Mountains. We set out to test whether co-infections of B and FWolbachiain hybrid grasshoppers enabled horizontal transfer of phage WO, similar to the numerous examples of phage WO transfer between A and BWolbachiaco-infections. While we found no evidence for transfer between the divergent co-infections, we discovered horizontal transfer of at least three phage WO haplotypes to the grasshopper genome. Subsequent genome sequencing of uninfected grasshoppers uncovered the first evidence for two discreteWolbachiasupergroups (B and F) contributing at least 448 kb and 144 kb of DNA, respectively, into the host nuclear genome. Fluorescentin situhybridization verified the presence ofWolbachiaDNA inC. paralleluschromosomes and revealed that some inserts are subspecies-specific while others are present in both subspecies. We discuss our findings in light of symbiont dynamics in an animal hybrid zone.

scholarly journals Opposing dominance within a color gene block is associated with maladaptive hybrid signal discordance

2021 ◽  
Author(s):  
Devin R. de Zwaan ◽  
Jacqueline Mackenzie ◽  
Else Mikklesen ◽  
Silu Wang
Keyword(s):  
Hybrid Zone ◽  
Social Dynamics ◽  
Color Variation ◽  
Species Boundaries ◽  
Gene Block ◽  
Behavioral Mechanism ◽  
Stable Species ◽  
Significant Gene ◽  
Behavioral Mechanisms ◽  
Social Signaling

AbstractColor divergence is increasingly recognized as important for speciation in songbirds through its influence on social dynamics. However, the behavioral mechanisms underlying the eco-evolutionary feedback that acts across species boundaries is poorly understood. The hybrid zone between Setophaga occidentalis (SOCC) and S. townsendi (STOW) in the Cascade mountain ranges provides a natural observatory to test the interplay between genetics and social behaviour in maintaining species boundaries. Recently, we found that selection within a gene block underpinning color variation (ASIP-RALY) has maintained a stable and narrow hybrid zone. Here we investigated the social signaling roles of cheek darkness and flank streaking, two color traits linked to ASIP-RALY that reflect opposing dominance of SOCC and STOW alleles. We found that both traits act as honest badges of status, as they predicted male breeding quality. The opposing dominance effects of ASIP-RALY resulted in signal discordance for heterozygotes, which in turn was associated with inferior hybrid territorial performance, a fitness proxy quantified by vocal and physical responses of resident males to a decoy intruder. Taken together, this study highlights a potential behavioral mechanism underlying selection acting on a simple genetic architecture that has maintained a stable species boundary over decades despite significant gene flow.

Calibration problems in hydrogen luminosities

1966 ◽  
Vol 24 ◽  
pp. 322-330
Author(s):  
A. Beer
Keyword(s):  
Galactic Structure ◽  
B Stars ◽  
Insight Into

The investigations which I should like to summarize in this paper concern recent photo-electric luminosity determinations of O and B stars. Their final aim has been the derivation of new stellar distances, and some insight into certain patterns of galactic structure.

Sign in / Sign up

Export Citation Format

Share Document