Color-Pattern Variation in Lake Erie Water Snakes: The Role of Gene Flow

Evolution ◽  
1995 ◽  
Vol 49 (5) ◽  
pp. 885 ◽  
Author(s):  
Richard B. King ◽  
Robin Lawson
Keyword(s):  
Gene Flow ◽  
Lake Erie ◽  
Color Pattern ◽  
Water Snakes

scholarly journals COLOR-PATTERN VARIATION IN LAKE ERIE WATER SNAKES: THE ROLE OF GENE FLOW

Evolution ◽  
1995 ◽  
Vol 49 (5) ◽  
pp. 885-896 ◽  
Author(s):  
Richard B. King ◽  
Robin Lawson
Keyword(s):  
Gene Flow ◽  
Lake Erie ◽  
Color Pattern ◽  
Water Snakes

Color pattern variation in Lake Erie water snakes: inheritance

1993 ◽  
Vol 71 (10) ◽  
pp. 1985-1990 ◽  
Author(s):  
Richard B. King
Keyword(s):  
Lake Erie ◽  
Genetic Basis ◽  
Genetic Correlations ◽  
Color Pattern ◽  
Nerodia Sipedon ◽  
Major Locus ◽  
Water Snake ◽  
Estimate Heritability ◽  
Opposing Effects ◽  
Water Snakes

The hypothesis that color pattern variation in Lake Erie island water snake (Nerodia sipedon) populations results from the opposing effects of natural selection and gene flow requires that this variation have a genetic basis. To determine whether color pattern variation is genetically based, data on the color pattern of wild-caught females and their captive-born offspring were used to estimate heritability of and correlations among four color pattern components. These data, and the results of two laboratory crosses, were also used to test for major locus influences on color pattern. Heritabilities of color pattern components estimated from sib analysis were significantly greater than zero for all four color pattern components, ranging from 0.34 to 0.79. Phenotypic and genetic correlations among color pattern components were positive, ranging from 0.24 to 0.55 (phenotypic correlations) and from 0.40 to 0.82 (genetic correlations). However, inheritance of color pattern was not strictly quantitative. Rather, a major locus appeared to influence color pattern, with alleles at this locus possibly determining whether snakes had regular (mainland-like) or reduced color patterns. Allele frequencies at this locus may have influenced the rate at which island and mainland water snake populations initially differentiated from each other, and may explain the lack of reduced-pattern morphs under similar selective regimes elsewhere.

scholarly journals Premating barriers in young sympatric snail species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arina L. Maltseva ◽  
Marina A. Varfolomeeva ◽  
Arseniy A. Lobov ◽  
Polina O. Tikanova ◽  
Egor A. Repkin ◽  
...  
Keyword(s):  
Gene Flow ◽  
Snail Species ◽  
Sympatric Populations ◽  
Gastropod Species ◽  
Shell Size ◽  
Closely Related Species ◽  
Partial Canonical Correspondence Analysis ◽  
In The Wild ◽  
Isolation Index

AbstractSympatric coexistence of recently diverged species raises the question of barriers restricting the gene flow between them. Reproductive isolation may be implemented at several levels, and the weakening of some, e.g. premating, barriers may require the strengthening of the others, e.g. postcopulatory ones. We analysed mating patterns and shell size of mates in recently diverged closely related species of the subgenus Littorina Neritrema (Littorinidae, Caenogastropoda) in order to assess the role of premating reproductive barriers between them. We compared mating frequencies observed in the wild with those expected based on relative densities using partial canonical correspondence analysis. We introduced the fidelity index (FI) to estimate the relative accuracy of mating with conspecific females and precopulatory isolation index (IPC) to characterize the strength of premating barriers. The species under study, with the exception of L. arcana, clearly demonstrated preferential mating with conspecifics. According to FI and IPC, L. fabalis and L. compressa appeared reliably isolated from their closest relatives within Neritrema. Individuals of these two species tend to be smaller than those of the others, highlighting the importance of shell size changes in gastropod species divergence. L. arcana males were often found in pairs with L. saxatilis females, and no interspecific size differences were revealed in this sibling species pair. We discuss the lack of discriminative mate choice in the sympatric populations of L. arcana and L. saxatilis, and possible additional mechanisms restricting gene flow between them.

scholarly journals Molecular Signatures of Reticulate Evolution within the Complex of European Pine Taxa

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 489
Author(s):  
Bartosz Łabiszak ◽  
Witold Wachowiak
Keyword(s):  
Gene Flow ◽  
Reticulate Evolution ◽  
Modeling Framework ◽  
Closely Related Species ◽  
Interspecific Gene Flow ◽  
Nucleotide Sequence Variation ◽  
History Of ◽  
Best Fitting ◽  
Species Integrity

Speciation mechanisms, including the role of interspecific gene flow and introgression in the emergence of new species, are the major focus of evolutionary studies. Inference of taxonomic relationship between closely related species may be challenged by past hybridization events, but at the same time, it may provide new knowledge about mechanisms responsible for the maintenance of species integrity despite interspecific gene flow. Here, using nucleotide sequence variation and utilizing a coalescent modeling framework, we tested the role of hybridization and introgression in the evolutionary history of closely related pine taxa from the Pinus mugo complex and P. sylvestris. We compared the patterns of polymorphism and divergence between taxa and found a great overlap of neutral variation within the P. mugo complex. Our phylogeny reconstruction indicated multiple instances of reticulation events in the past, suggesting an important role of interspecific gene flow in the species divergence. The best-fitting model revealed P. mugo and P. uncinata as sister species with basal P. uliginosa and asymmetric migration between all investigated species after their divergence. The magnitude of interspecies gene flow differed greatly, and it was consistently stronger from representatives of P. mugo complex to P. sylvestris than in the opposite direction. The results indicate the prominent role of reticulation evolution in those forest trees and provide a genetic framework to study species integrity maintained by selection and local adaptation.

Introgression between non-sister species of honeyeaters (Aves: Meliphagidae) several million years after speciation

2019 ◽  
Vol 128 (3) ◽  
pp. 583-591
Author(s):  
Leo Joseph ◽  
Alex Drew ◽  
Ian J Mason ◽  
Jeffrey L Peters
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Sex Chromosomes ◽  
Common Ancestor ◽  
Sister Species ◽  
Species Boundaries ◽  
North Eastern ◽  
The City

Abstract We reassessed whether two parapatric non-sister Australian honeyeater species (Aves: Meliphagidae), varied and mangrove honeyeaters (Gavicalis versicolor and G. fasciogularis, respectively), that diverged from a common ancestor c. 2.5 Mya intergrade in the Townsville area of north-eastern Queensland. Consistent with a previous specimen-based study, by using genomics methods we show one-way gene flow for autosomal but not Z-linked markers from varied into mangrove honeyeaters. Introgression barely extends south of the area of parapatry in and around the city of Townsville. While demonstrating the long-term porosity of species boundaries over several million years, our data also suggest a clear role of sex chromosomes in maintaining reproductive isolation.

The role of plastic debris in the biogeochemical cycle of mercury in Lake Erie and San Francisco Bay

2021 ◽  
Vol 171 ◽  
pp. 112768
Author(s):  
Katlin L. Bowman ◽  
Carl H. Lamborg ◽  
Alison M. Agather ◽  
Chad R. Hammerschmidt
Keyword(s):  
San Francisco ◽  
Lake Erie ◽  
San Francisco Bay ◽  
Biogeochemical Cycle ◽  
Plastic Debris

scholarly journals The role of boundary length and adjacent patch contrast in guppy mate choice

2020 ◽  
Author(s):  
Adélaïde Sibeaux ◽  
Thomas Camduras ◽  
John A Endler
Keyword(s):  
Mate Choice ◽  
Coefficient Of Variation ◽  
Color Pattern ◽  
Strength Analysis ◽  
Visual Contrast ◽  
Female Preferences ◽  
Signal Amplifier ◽  
Polymorphic Species ◽  
Adjacent Patch

Abstract The presence of various combinations of adjacent colors within polymorphic species’ color pattern could have a major impact on mate choice. We studied the role of pattern geometry in predicting mate choice in guppies using boundary strength analysis (BSA). BSA estimates the visual contrast intensity between two adjacent color patches (ΔS) weighted by the lengths of the boundaries between these adjacent color patches. We measured both the chromatic (hue and saturation) and achromatic (luminance) ΔS for each pair of adjacent patches. For each male’s color pattern, we measured BSA as both mean (mΔS) and coefficient of variation (cvΔS) of all ΔS weighted by their corresponding boundary lengths. We also determined if specific color patch boundaries had an impact on female preferences and whether these predicted overall male contrast (mΔS). We found that males with a higher mΔS were more attractive to females and that six boundaries containing either fuzzy black or black as one of the pair colors significantly affected female preferences, indicating that 1) females favored highly conspicuous males and 2) melanin-based patches could be used as a signal amplifier, not only for orange but for other colors.

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