scholarly journals A tale of two seas: contrasting patterns of population structure in the small-spotted catshark across Europe

2014 ◽  
Vol 1 (3) ◽  
pp. 140175 ◽  
Author(s):  
Chrysoula Gubili ◽  
David W. Sims ◽  
Ana Veríssimo ◽  
Paolo Domenici ◽  
Jim Ellis ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Spatial Scales ◽  
Sea Level Changes ◽  
Glacial Cycles ◽  
Mediterranean Populations ◽  
Population Reduction ◽  
The Mediterranean

Elasmobranchs represent important components of marine ecosystems, but they can be vulnerable to overexploitation. This has driven investigations into the population genetic structure of large-bodied pelagic sharks, but relatively little is known of population structure in smaller demersal taxa, which are perhaps more representative of the biodiversity of the group. This study explores spatial population genetic structure of the small-spotted catshark ( Scyliorhinus canicula ), across European seas. The results show significant genetic differences among most of the Mediterranean sample collections, but no significant structure among Atlantic shelf areas. The data suggest the Mediterranean populations are likely to have persisted in a stable and structured environment during Pleistocene sea-level changes. Conversely, the Northeast Atlantic populations would have experienced major changes in habitat availability during glacial cycles, driving patterns of population reduction and expansion. The data also provide evidence of male-biased dispersal and female philopatry over large spatial scales, implying complex sex-determined differences in the behaviour of elasmobranchs. On the basis of this evidence, we suggest that patterns of connectivity are determined by trends of past habitat stability that provides opportunity for local adaptation in species exhibiting philopatric behaviour, implying that resilience of populations to fisheries and other stressors may differ across the range of species.

scholarly journals Birds are islands for parasites

2014 ◽  
Vol 10 (8) ◽  
pp. 20140255 ◽  
Author(s):  
Jennifer A. H. Koop ◽  
Karen E. DeMatteo ◽  
Patricia G. Parker ◽  
Noah K. Whiteman
Keyword(s):  
Population Structure ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Evolutionary Biology ◽  
Isolation By Distance ◽  
Spatial Scales ◽  
Island Populations ◽  
Louse Species ◽  
Parasite Populations

Understanding the mechanisms driving the extraordinary diversification of parasites is a major challenge in evolutionary biology. Co-speciation, one proposed mechanism that could contribute to this diversity is hypothesized to result from allopatric co-divergence of host–parasite populations. We found that island populations of the Galápagos hawk ( Buteo galapagoensis ) and a parasitic feather louse species ( Degeeriella regalis ) exhibit patterns of co-divergence across variable temporal and spatial scales. Hawks and lice showed nearly identical population genetic structure across the Galápagos Islands. Hawk population genetic structure is explained by isolation by distance among islands. Louse population structure is best explained by hawk population structure, rather than isolation by distance per se , suggesting that lice tightly track the recent population histories of their hosts. Among hawk individuals, louse populations were also highly structured, suggesting that hosts serve as islands for parasites from an evolutionary perspective. Altogether, we found that host and parasite populations may have responded in the same manner to geographical isolation across spatial scales. Allopatric co-divergence is likely one important mechanism driving the diversification of parasites.

Significant genetic differences among Heterodera schachtii populations within and among sugar beet production areas

Nematology ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 165-177 ◽  
Author(s):  
Rasha Haj Nuaima ◽  
Johannes Roeb ◽  
Johannes Hallmann ◽  
Matthias Daub ◽  
Holger Heuer
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Spatial Scales ◽  
Geographic Distance ◽  
Heterodera Schachtii ◽  
Parasitic Nematodes ◽  
Neutral Genetic Variation ◽  
Production Areas

Summary Characterising the non-neutral genetic variation within and among populations of plant-parasitic nematodes is essential to determine factors shaping the population genetic structure. This study describes the genetic variation of the parasitism gene vap1 within and among geographic populations of the beet cyst nematode Heterodera schachtii. Forty populations of H. schachtii were sampled at four spatial scales: 695 km, 49 km, 3.1 km and 0.24 km. DGGE fingerprinting showed significant differences in vap1 patterns among populations. High similarity of vap1 patterns appeared between geographically close populations, and occasionally among distant populations. Analysis of spatially sampled populations within fields revealed an effect of tillage direction on the vap1 similarity for two of four studied fields. Overall, geographic distance and similarity of vap1 patterns of H. schachtii populations were negatively correlated. In conclusion, the population genetic structure was shaped by the interplay between the genetic adaptation and the passive transport of this nematode.

Population genetic structure inMyrtus communisL. in a chronically fragmented landscape in the Mediterranean: can gene flow counteract habitat perturbation?

Plant Biology ◽  
2009 ◽  
Vol 11 (3) ◽  
pp. 442-453 ◽  
Author(s):  
R. G. Albaladejo ◽  
L. F. Carrillo ◽  
A. Aparicio ◽  
J. F. Fernández-Manjarrés ◽  
J. P. González-Varo
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Fragmented Landscape ◽  
The Mediterranean

scholarly journals Population structure of Opisthorchis felineus (Trematoda) and its second intermediate hosts — cyprinid fishes in the Ob-Irtysh focus of opisthorchiasis, based on allozyme data

2014 ◽  
Vol 51 (4) ◽  
pp. 309-317 ◽  
Author(s):  
O. Zhigileva ◽  
V. Ozhireľev ◽  
T. Stepanova ◽  
T. Moiseenko
Keyword(s):  
Population Structure ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Allozyme Variation ◽  
Intermediate Hosts ◽  
Opisthorchis Felineus ◽  
Cyprinid Fishes ◽  
Low Levels

AbstractGenetic variability of West Siberian populations of Opisthorchis felineus and two species of cyprinid fish, its second intermediate hosts, was studied by isozyme analysis. Low levels of allozyme variation and genetic differentiation in O. felineus from the Ob-Irtysh focus of opisthorchiasis were detected. The proportion of polymorphic loci was 21.1 %, the average observed heterozygosity (Hobs) was 0.008, and expected heterozygosity (Hexp) was 0.052. For most loci in O. felineus deficit of heterozygotes (FIS = 0.7424) was observed. A comparison of population genetic structure of fish and parasites showed they were not congruent. Estimates of genetic differentiation of the parasite were smaller than for the fish — its intermediate host. Migration and population structure of the second intermediate hosts do not play an important role in formation of the population-genetic structure of O. felineus in the Ob-Irtysh focus of opisthorchiasis.

scholarly journals Population genetic structure of the tree-hole tick Ixodes arboricola (Acari: Ixodidae) at different spatial scales

Heredity ◽  
2014 ◽  
Vol 113 (5) ◽  
pp. 408-415 ◽  
Author(s):  
A R Van Oosten ◽  
D J A Heylen ◽  
K Jordaens ◽  
T Backeljau ◽  
E Matthysen
Keyword(s):  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Spatial Scales ◽  
Tree Hole ◽  
Ixodes Arboricola

scholarly journals Allele frequencies in loci controlling coat colour in Polish Coldblood horses

2018 ◽  
Vol 63 (No. 11) ◽  
pp. 462-472
Author(s):  
Anna Stachurska ◽  
Antoni Brodacki ◽  
Marta Liss
Keyword(s):  
Population Structure ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Coat Colour ◽  
Allele Frequencies ◽  
Square Root ◽  
Horse Population ◽  
Hardy Weinberg Equilibrium ◽  
Recessive Phenotype

The objective of this study was to estimate the frequencies of alleles which produce coat colour in Polish Coldblood horse population, and to verify the hypothesis that coat colour is not considered in its selection. The analysis included 35 928 horses and their parents having been registered in the studbook over a half-century. Allele frequencies in Agouti (A), Extension (E), Dun (D), Roan (Rn), and Grey (G) loci, in parental and offspring generations, were estimated according to test matings and the square root of recessive phenotype frequency. The population structure is in Hardy–Weinberg equilibrium only at E locus and coat colour is regarded by breeders. Black horses are favoured. Higher E locus homozygosity in blacks than in bays makes it easier to obtain black foals. Dun-diluted, roan and grey coat colours are undesirable and the population has come to consist almost uniformly of basic coat colours. These results show the importance of studies on population genetic structure, which despite no formal criteria for breeding for colour, can considerably change through generations.

Contrasting population genetic structure of two widespread aquatic insects in the Chilean high-slope rivers

2011 ◽  
Vol 62 (1) ◽  
pp. 1 ◽  
Author(s):  
M. C. Sabando ◽  
I. Vila ◽  
R. Peñaloza ◽  
D. Véliz
Keyword(s):  
Population Structure ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Aquatic Insects ◽  
Population Genetic ◽  
Nuclear Markers ◽  
Widespread Species ◽  
Central Chile ◽  
Physical Barriers ◽  
Three Rivers

Dispersal and many other factors affect population genetic structure. In central Chile, rivers are characterised by strong currents and transverse mountain chains, which impose physical barriers to the populations that inhabit them. The objective of the present study was to study the population genetic structure of two widespread species of aquatic insects, the caddisfly Smicridea annulicornis and the mayfly Andesiops torrens, in three isolated rivers, Choapa, Maipo and Maule. The analysis of population structure, using both mtDNA (cytochrome C oxidase subunit 1, COI) and nuclear markers (amplified fragment length polymorphism, AFLP), considered samples from within and among rivers. In S. annulicornis, we found differentiation within and among rivers, indicating a low dispersal among the study area. Populations of A. torrens shared haplotypes in all three rivers and no differences were found among rivers, indicating that this species probably has more dispersal potential than does S. annulicornis; however, significant differences were observed within rivers. Our results indicate that the transverse mountain chains are not a barrier for A. torrens, which can disperse among rivers. Within rivers, the population structure suggests that these species are probably adapted to avoid drift because of the torrential character of these Chilean rivers.

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