Stable climate corridors promote gene flow in the Cape sand snake species complex (Psammophiidae)

ABSTRACTKlebsiella species are able to colonize a wide range of environments and include worrisome nosocomial pathogens. Here, we sought to determine the abundance and infectivity of prophages of Klebsiella to understand how the interactions between induced prophages and bacteria affect population dynamics and evolution. We identified many prophages in the species, placing these taxa among the top 5% of the most polylysogenic bacteria. We selected 35 representative strains of the Klebsiella pneumoniae species complex to establish a network of induced phage-bacteria interactions. This revealed that many prophages are able to enter the lytic cycle, and subsequently kill or lysogenize closely-related Klebsiella strains. Although 60% of the tested strains could produce phages that infect at least one other strain, the interaction network of all pairwise cross-infections is very sparse and mostly organized in modules corresponding to the strains’ capsule serotypes. Accordingly, capsule mutants remain uninfected showing that the capsule is a key factor for successful infections. Surprisingly, experiments in which bacteria are predated by their own prophages result in accelerated loss of the capsule. Our results show that phage infectiousness defines interaction modules between small subsets of phages and bacteria in function of capsule serotype. This limits the role of prophages as competitive weapons because they can infect very few strains of the species complex. This should also restrict phage-driven gene flow across the species. Finally, the accelerated loss of the capsule in bacteria being predated by their own phages, suggests that phages drive serotype switch in nature.

Download Full-text

Environmental effects on gene flow in a species complex of vagile, hilltopping butterflies

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blz043 ◽

2019 ◽

Vol 127 (2) ◽

pp. 417-428 ◽

Cited By ~ 1

Author(s):

Julian R Dupuis ◽

Catherine I Cullingham ◽

Scott E Nielsen ◽

Felix A H Sperling

Keyword(s):

Gene Flow ◽

Environmental Effects ◽

Species Complex

Download Full-text

The influence of gene flow on latitudinal clines of photoperiodic adult diapause in the Drosophila auraria species-complex

Biological Journal of the Linnean Society ◽

10.1111/j.1095-8312.1993.tb02095.x ◽

1993 ◽

Vol 48 (4) ◽

pp. 335-341 ◽

Cited By ~ 15

Author(s):

MASAHITO T. KIMURA ◽

AKIRA BESSHO ◽

ZHUO-HUA DAI

Keyword(s):

Gene Flow ◽

Species Complex ◽

Adult Diapause ◽

Latitudinal Clines

Download Full-text

Genetic and morphological differentiation among populations of the Rivoli’s Hummingbird (Eugenes fulgens) species complex (Aves: Trochilidae)

The Auk ◽

10.1093/auk/ukaa032 ◽

2020 ◽

Vol 137 (4) ◽

Cited By ~ 1

Author(s):

Luz E Zamudio-Beltrán ◽

Juan Francisco Ornelas ◽

Andreia Malpica ◽

Blanca E Hernández-Baños

Keyword(s):

Genetic Variation ◽

Gene Flow ◽

Genetic Differentiation ◽

Species Complex ◽

Ecological Niche Modeling ◽

Demographic History ◽

Morphological Differentiation ◽

Last Interglacial ◽

Haplotype Networks ◽

Isthmus Of Tehuantepec

Abstract Genetic variation and phylogeographic studies have been crucial for understanding mechanisms of speciation. We analyzed genetic variation and phylogeography to reconstruct the demographic history of the Rivoli’s Hummingbird (Eugenes fulgens) species complex and also evaluated their morphological differentiation. This widely distributed species inhabits the highlands of Mexico and northern Central America, with 2 subspecies separated by the Isthmus of Tehuantepec (west: E. f. fulgens, east: E. f. viridiceps). We surveyed genetic variation in 2 mitochondrial DNA markers (mtDNA, with 129 individuals) and nuclear DNA (6 microsatellites, with 85 individuals). We also inferred the demographic history, estimated divergence times, and analyzed morphological variation using 470 vouchered specimens. We modeled the current potential distribution of the species using ecological niche modeling and projected it into the past to model the effects of the Pleistocene climatic cycles. Haplotype networks, pairwise FST comparisons, AMOVA, and morphological analysis revealed differences between geographically isolated populations separated by the Isthmus of Tehuantepec (IT; corresponding to the 2 recognized subspecies: fulgens and viridiceps), and by the Motagua-Polochic-Jocotán (MPJ) system fault. Demographic scenarios revealed a contraction in distribution during the last interglacial, and expansion during the Last Glacial Maximum (LGM) with little change since the LGM. Divergence between groups separated by the Isthmus of Tehuantepec ~59,600 yr ago occurred in the presence of gene flow, suggesting that the Isthmus of Tehuantepec is a semipermeable barrier to gene flow. STRUCTURE analyses of microsatellite data detected 3 genetically differentiated groups. Several results fit a model of recent lineage divergence, including a significant signal of genetic differentiation, demographic expansion, decreased gene flow from past to present, and northward expansion during the LGM and contraction during the interglacial periods. We conclude that the genetic differentiation of E. fulgens in the Madrean Pine-Oak Woodlands resulted from recent geographical isolation of populations separated by natural barriers (IT and MPJ).

Download Full-text

Local human pressures influence gene flow in a hybridizing Daphnia species complex

Journal of Evolutionary Biology ◽

10.1111/jeb.12820 ◽

2016 ◽

Vol 29 (4) ◽

pp. 720-735 ◽

Cited By ~ 10

Author(s):

B. Alric ◽

M. Möst ◽

I. Domaizon ◽

C. Pignol ◽

P. Spaak ◽

...

Keyword(s):

Gene Flow ◽

Species Complex ◽

Daphnia Species

Download Full-text

Ancient polymorphisms and divergence hitchhiking contribute to genomic islands of divergence within a poplar species complex

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1713288114 ◽

2017 ◽

Vol 115 (2) ◽

pp. E236-E243 ◽

Cited By ~ 45

Author(s):

Tao Ma ◽

Kun Wang ◽

Quanjun Hu ◽

Zhenxiang Xi ◽

Dongshi Wan ◽

...

Keyword(s):

Gene Flow ◽

Species Complex ◽

Populus Euphratica ◽

Genomic Islands ◽

Ecological Selection ◽

Poplar Trees ◽

Genomic Divergence ◽

Genome Divergence ◽

Genomic Regions ◽

Time Of Divergence

How genome divergence eventually leads to speciation is a topic of prime evolutionary interest. Genomic islands of elevated divergence are frequently reported between diverging lineages, and their size is expected to increase with time and gene flow under the speciation-with-gene-flow model. However, such islands can also result from divergent sorting of ancient polymorphisms, recent ecological selection regardless of gene flow, and/or recurrent background selection and selective sweeps in low-recombination regions. It is challenging to disentangle these nonexclusive alternatives, but here we attempt to do this in an analysis of what drove genomic divergence between four lineages comprising a species complex of desert poplar trees. Within this complex we found that two morphologically delimited species, Populus euphratica and Populus pruinosa, were paraphyletic while the four lineages exhibited contrasting levels of gene flow and divergence times, providing a good system for testing hypotheses on the origin of divergence islands. We show that the size and number of genomic islands that distinguish lineages are not associated with either rate of recent gene flow or time of divergence. Instead, they are most likely derived from divergent sorting of ancient polymorphisms and divergence hitchhiking. We found that highly diverged genes under lineage-specific selection and putatively involved in ecological and morphological divergence occur both within and outside these islands. Our results highlight the need to incorporate demography, absolute divergence measurement, and gene flow rate to explain the formation of genomic islands and to identify potential genomic regions involved in speciation.

Download Full-text