Diet breadth and its relationship with genetic diversity and differentiation: the case of southern beech aphids (Hemiptera: Aphididae)

AbstractHerbivorous insect species with narrow diet breadth are expected to be more prone to genetic differentiation than insect species with a wider diet breadth. However, a generalist can behave as a local specialist if a single host-plant species is locally available, while a specialist can eventually behave as a generalist if its preferred host is not available. These problems can be addressed by comparing closely related species differing in diet breadth with overlapping distributions of insect and host populations. In this work, diet breadth, genetic diversity and population differentiation of congeneric aphid species from southern beech forests in Chile were compared. While at the species level no major differences in genetic diversity were found, a general trend towards higher genetic diversity as diet breadth increased was apparent. The aphid species with wider diet breadth, Neuquenaphis edwardsi (Laing), showed the highest genetic diversity, while the specialist Neuquenaphis staryi Quednau & Remaudière showed the lowest. These differences were less distinct when the comparisons were made in the same locality and over the same host. Comparison of allopatric populations indicates that genetic differentiation was higher for the specialists, Neuquenaphis similis Hille Ris Lambers and N. staryi, than for the generalist N. edwardsi. Over the same host at different locations, genetic differentiation among populations of N. edwardsi was higher than among populations of N. similis. The results support the assumption that specialists should show more pronounced genetic structuring than generalists, although the geographical distribution of host plants may be playing an important role.

Download Full-text

Geographic hierarchical population genetic structuring in British European whitefish (Coregonus lavaretus) and its implications for conservation

Conservation Genetics ◽

10.1007/s10592-020-01298-y ◽

2020 ◽

Vol 21 (5) ◽

pp. 927-939

Author(s):

M. Crotti ◽

C. E. Adams ◽

E. C. Etheridge ◽

C. W. Bean ◽

A. R. D. Gowans ◽

...

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Great Britain ◽

Genetic Differentiation ◽

Principal Component ◽

Taxonomic Revision ◽

Coregonus Lavaretus ◽

Genetic Structuring ◽

Separate Species ◽

Native Populations

Abstract The European whitefish Coregonus lavaretus complex represents one of the most diverse radiations within salmonids, with extreme morphological and genetic differentiation across its range. Such variation has led to the assignment of many populations to separate species. In Great Britain, the seven native populations of C. lavaretus (two in Scotland, four in England, one in Wales) were previously classified into three species, and recent taxonomic revision resurrected the previous nomenclature. Here we used a dataset of 15 microsatellites to: (1) investigate the genetic diversity of British populations, (2) assess the level of population structure and the relationships between British populations. Genetic diversity was highest in Welsh (HO = 0.50, AR = 5.29), intermediate in English (HO = 0.41–0.50, AR = 2.83–3.88), and lowest in Scottish populations (HO = 0.28–0.35, AR = 2.56–3.04). Population structure analyses indicated high genetic differentiation (global FST = 0.388) between all populations but for the two Scottish populations (FST = 0.063) and two English populations (FST = 0.038). Principal component analysis and molecular ANOVA revealed separation between Scottish, English, and Welsh populations, with the Scottish populations being the most diverged. We argue that the data presented here are not sufficient to support a separation of the British European whitefish populations into three separate species, but support the delineation of different ESUs for these populations.

Download Full-text

Genetic Diversity and Population Structure of Medemia argun (Mart.) Wurttenb. ex H.Wendl. Based on Genome-Wide Markers

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.687188 ◽

2021 ◽

Vol 9 ◽

Author(s):

Sakina Elshibli ◽

Helena Korpelainen

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Genetic Differentiation ◽

Conservation Status ◽

Ex Situ ◽

Conservation Strategies ◽

Nucleotide Polymorphisms ◽

Genetic Structuring ◽

Ancestral Gene ◽

Low Genetic Diversity

Medemia argun is a wild, dioecious palm, adapted to the harsh arid environment of the Nubian Desert in Sudan and southern Egypt. There is a concern about its conservation status, since little is known about its distribution, abundance, and genetic variation. M. argun grows on the floodplains of seasonal rivers (wadis). The continuing loss of suitable habitats in the Nubian Desert is threatening the survival of this species. We analyzed the genetic diversity, population genetic structure, and occurrence of M. argun populations to foster the development of conservation strategies for M. argun. Genotyping-by-sequencing (GBS) analyses were performed using a whole-genome profiling service. We found an overall low genetic diversity and moderate genetic structuring based on 40 single-nucleotide polymorphisms (SNPs) and 9,866 SilicoDArT markers. The expected heterozygosity of the total population (HT) equaled 0.036 and 0.127, and genetic differentiation among populations/groups (FST) was 0.052 and 0.092, based on SNP and SilicoDArT markers, respectively. Bayesian clustering analyses defined five genetic clusters that did not display any ancestral gene flow among each other. Based on SilicoDArT markers, the results of the analysis of molecular variance (AMOVA) confirmed the previously observed genetic differentiation among generation groups (23%; p < 0.01). Pairwise FST values indicated a genetic gap between old and young individuals. The observed low genetic diversity and its loss among generation groups, even under the detected high gene flow, show genetically vulnerable M. argun populations in the Nubian Desert in Sudan. To enrich and maintain genetic variability in these populations, conservation plans are required, including collection of seed material from genetically diverse populations and development of ex situ gene banks.

Download Full-text

Intra- and interspecific allozyme variation in eucalypts from the spotted gum group, Corymbia, section 'Politaria' (Myrtaceae)

Australian Systematic Botany ◽

10.1071/sb00005 ◽

2000 ◽

Vol 13 (4) ◽

pp. 491 ◽

Cited By ~ 9

Author(s):

M. W. McDonald ◽

P. A. Butcher ◽

J. C. Bell ◽

J. S. Larmour

Keyword(s):

Genetic Diversity ◽

Genetic Variation ◽

Genetic Differentiation ◽

Related Species ◽

Allozyme Variation ◽

Geographic Range ◽

Breeding Systems ◽

Closely Related Species ◽

Tropical Regions ◽

Corymbia Citriodora

The distribution of genetic variation within and among species inCorymbia section‘Politaria’ was examined using allozymes.This section consists of four species,Corymbia citriodora (Hook.) K.D.Hill & L.A.S.Johnson, C. maculata (Hook.) K.D.Hill & L.A.S.Johnson, C. henryi (Blake) K.D.Hill & L.A.S.Johnson and C. variegata (F.Muell.) K.D.Hill & L.A.S.Johnson, which are of commercial interest for plantation and farmforestry. Thirty populations representing the species’ range-widedistributions were studied, extending from upland tropical regions of northQueensland, south to eastern Victoria. Despite relatively low allozymedivergence between species, there was a relationship between geographicdistribution patterns of populations and allozyme variation. The section wasshown to comprise very closely related species with only 15% of thetotal genetic diversity attributed to differences between species. Twodistinct genetic alliances were evident:C. maculata–C. henryi andC. citriodora–C. variegata.Corymbia citriodora andC. variegata, however, could not be distinguished bytheir allozyme profiles. The lack of genetic differentiation between thesetaxa suggests that they represent one species composed of two chemical races.Corymbia maculata and C. henryiwere shown to be closely allied but genetically distinct.Corymbia henryi had the highest genetic diversity in thegroup and lowest differentiation among populations, whileC. maculata had the lowest diversity but the highestgenetic differentiation among populations. There was evidence ofisolation-by-distance among populations ofC. citriodora, C. maculata andC. variegata but not in C. henryi,which has a smaller geographic range. The inclusion in the study ofC. torelliana (F.Muell.) K.D.Hill & L.A.S.Johnson asan outgroup accentuated the small genetic differences between species in thegroup. The patterns of genetic diversity are discussed in relation to thespecies’ taxonomic relationships, breeding systems and utilisation.

Download Full-text

Genetic differentiation in two European tree frog (Hyla arborea) metapopulations in contrasted landscapes of western Switzerland

Amphibia-Reptilia ◽

10.1163/156853809787392775 ◽

2009 ◽

Vol 30 (1) ◽

pp. 127-133 ◽

Cited By ~ 7

Author(s):

Sylvain Dubey ◽

Luca Fumagalli ◽

Sylvain Ursenbacher ◽

Jérôme Pellet

Keyword(s):

Genetic Diversity ◽

Gene Flow ◽

Genetic Differentiation ◽

Tree Frog ◽

Genetic Structuring ◽

Hyla Arborea ◽

Heterogeneous Landscape ◽

Loss Of Genetic Diversity ◽

Suitable Habitats ◽

Two Sectors

AbstractThe survival of threatened species as the European tree frog (Hyla arborea) is strongly dependent on the genetic variability within populations, as well as gene flow between them. In Switzerland, only two sectors in its western part still harbour metapopulations. The first is characterised by a very heterogeneous and urbanized landscape, while the second is characterised by a uninterrupted array of suitable habitats. In this study, six microsatellite loci were used to establish levels of genetic differentiation among the populations from the two different locations. The results show that the metapopulations have: (i) weak levels of genetic differentiation (FST within metapopulation ≈ 0.04), (ii) no difference in levels of genetic structuring between them, (iii) significant (p = 0.019) differences in terms of genetic diversity (Hs) and observed heterozygozity (Ho), the metapopulation located in a disturbed landscape showing lower values. Our results suggest that even if the dispersal of H. arborea among contiguous ponds seems to be efficient in areas of heterogeneous landscape, a loss of genetic diversity can occur.

Download Full-text

Corrigendum to: Intra- and interspecific allozyme variation in eucalypts from the spotted gum group, Corymbia, section 'Politaria' (Myrtaceae)

Australian Systematic Botany ◽

10.1071/sb00005_co ◽

2003 ◽

Vol 16 (5) ◽

pp. 643 ◽

Cited By ~ 4

Author(s):

M. W. McDonald ◽

P. A. Butcher ◽

J. S. Larmour ◽

J. C. Bell

Keyword(s):

Genetic Diversity ◽

Genetic Variation ◽

Genetic Differentiation ◽

Related Species ◽

Allozyme Variation ◽

Geographic Range ◽

Breeding Systems ◽

Closely Related Species ◽

Tropical Regions ◽

Corymbia Citriodora

Download Full-text

Strong genetic differentiation among populations of the freshwater shrimp Caridina cantonensis in Hong Kong: implications for conservation of freshwater fauna in urban areas

Marine and Freshwater Research ◽

10.1071/mf15377 ◽

2017 ◽

Vol 68 (1) ◽

pp. 187 ◽

Cited By ~ 1

Author(s):

Ling Ming Tsang ◽

Kwok Ho Tsoi ◽

Simon Kin-Fung Chan ◽

Tony King-Tung Chan ◽

Ka Hou Chu

Keyword(s):

Genetic Diversity ◽

Hong Kong ◽

Genetic Differentiation ◽

Urban Areas ◽

Habitat Destruction ◽

Freshwater Shrimp ◽

Genetic Structuring ◽

Unique Haplotype ◽

High Genetic Diversity ◽

Mitochondrial Coi

Freshwater organisms generally exhibit strong genetic structuring. Although understanding the level and spatial distribution of genetic diversity is crucial for conservation management planning, such information has received little attention until recently in highly developed cities where local extinction attributed to habitat destruction and urbanisation is intense. We compared the genetic divergence in mitochondrial COI of the freshwater shrimp Caridina cantonensis collected from 32 sites in Hong Kong, to determine the connectivity among populations and the levels of genetic diversity of the shrimp. We found that shrimp from different streams are genetically highly differentiated and each stream always has its own unique haplotype groups, even though some of the streams are separated only by a few kilometres, indicating very limited gene flow across streams. Moreover, genetic diversity within each stream is very low, usually with a single haplotype dominating the entire population, and genetic differentiation was observed among tributaries from the same drainage. The high genetic diversity of these species over short distances has significant conservation implications because a substantial amount of biodiversity may have already been lost as a result of past development. Careful conservation planning is essential for future development in Hong Kong and other cities.

Download Full-text

Genetic Diversity, Population Structure, and Migration Scenarios of the Marsupial “Monito del Monte” in South-Central Chile

Journal of Heredity ◽

10.1093/jhered/esz049 ◽

2019 ◽

Vol 110 (6) ◽

pp. 651-661

Author(s):

Alejandro Valladares-Gómez ◽

Juan L Celis-Diez ◽

Constanza Sepúlveda-Rodríguez ◽

Oscar Inostroza-Michael ◽

Cristián E Hernández ◽

...

Keyword(s):

Genetic Diversity ◽

Genetic Differentiation ◽

Taxonomic Status ◽

Clustering Methods ◽

Genetic Structuring ◽

Living Fossil ◽

Central Chile ◽

South Central ◽

Genetic Clusters ◽

And Migration

Abstract In this study, we quantified the 3 pivotal genetic processes (i.e., genetic diversity, spatial genetic structuring, and migration) necessary for a better biological understanding and management of the singular “living-fossil” and near-threatened mouse opossum marsupial Dromiciops gliroides, the “Monito del Monte,” in south-central Chile. We used 11 microsatellite loci to genotype 47 individuals distributed on the mainland and northern Chiloé Island. Allelic richness, observed and expected heterozygosity, inbreeding coefficient, and levels of genetic differentiation were estimated. The genetic structure was assessed based on Bayesian clustering methods. In addition, potential migration scenarios were evaluated based on a coalescent theory framework and Bayesian approach to parameter estimations. Microsatellites revealed moderate to high levels of genetic diversity across sampled localities. Moreover, such molecular markers suggested that at least 2 consistent genetic clusters could be identified along the D. gliroides distribution (“Northern” and “Southern” cluster). However, general levels of genetic differentiation observed among localities and between the 2 genetic clusters were relatively low. Migration analyses showed that the most likely routes of migration of D. gliroides occurred 1) from the Southern cluster to the Northern cluster and 2) from the Mainland to Chiloé Island. Our results could represent critical information for future conservation programs and for a recent proposal about the taxonomic status of this unique mouse opossum marsupial.

Download Full-text

Stand out from the Crowd: Small-Scale Genetic Structuring in the Endemic Sicilian Pond Turtle

Diversity ◽

10.3390/d12090343 ◽

2020 ◽

Vol 12 (9) ◽

pp. 343

Author(s):

Luca Vecchioni ◽

Federico Marrone ◽

Marco Arculeo ◽

Uwe Fritz ◽

Melita Vamberger

Keyword(s):

Genetic Diversity ◽

Microsatellite Loci ◽

Small Scale ◽

Moderate Degree ◽

Geographical Pattern ◽

Genetic Structuring ◽

Pond Turtle ◽

Emys Trinacris ◽

Polymorphic Microsatellite ◽

Entire Distribution

The geographical pattern of genetic diversity was investigated in the endemic Sicilian pond turtle Emys trinacris across its entire distribution range, using 16 microsatellite loci. Overall, 245 specimens of E. trinacris were studied, showing high polymorphic microsatellite loci, with allele numbers ranging from 7 to 30. STRUCTURE and GENELAND analyses showed a noteworthy, geographically based structuring of the studied populations in five well-characterized clusters, supported by a moderate degree of genetic diversity (FST values between 0.075 and 0.160). Possible explanations for the genetic fragmentation observed are provided, where both natural and human-mediated habitat fragmentation of the Sicilian wetlands played a major role in this process. Finally, some conservation and management suggestions aimed at preventing the loss of genetic variability of the species are briefly reported, stressing the importance of considering the five detected clusters as independent Management Units.

Download Full-text

Genetic melting pot and importance of long-distance dispersal indicated in the Gladiolus imbricatus L. populations in the Polish Carpathians

Scientific Reports ◽

10.1038/s41598-021-96135-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Agnieszka Sutkowska ◽

Józef Mitka ◽

Tomasz Warzecha ◽

Jakub Bunk ◽

Julia Rutkowska ◽

...

Keyword(s):

Genetic Diversity ◽

Diversity Indices ◽

Western Carpathians ◽

Genetic Structuring ◽

Long Distance ◽

Plant Populations ◽

Genetic Stock ◽

Melting Pot ◽

Mountain Ranges ◽

Eastern Carpathians

AbstractThe genetic diversity in 11 populations of Gladiolus imbricatus in five mountain ranges, including the Tatra, Pieniny, Gorce, Beskid Niski (Western Carpathians) and Bieszczady Mts (Eastern Carpathians), was studied with inter-simple sequence repeat (ISSR) markers. The species is a perennial plant occurring in open and semi-open sites of anthropogenic origin (meadows and forest margins). We checked a hypothesis on the microrefugial character of the plant populations in the Pieniny Mts, a small calcareous Carpathian range of complicated relief that has never been glaciated. Plant populations in the Tatra and Pieniny Mts had the highest genetic diversity indices, pointing to their long-term persistence. The refugial vs. the non-refugial mountain ranges accounted for a relatively high value of total genetic variation [analysis of molecular variance (AMOVA), 14.12%, p = 0.003]. One of the Pieniny populations was of hybridogenous origin and shared genetic stock with the Tatra population, indicating there is a local genetic melting pot. A weak genetic structuring of populations among particular regions was found (AMOVA, 4.5%, p > 0.05). This could be an effect of the frequent short-distance and sporadic long-distance gene flow. The dispersal of diaspores between the remote populations in the Western Carpathians and Eastern Carpathians could be affected by the historical transportation of flocks of sheep from the Tatra to Bieszczady Mts.

Download Full-text

Comparative assessment of genetic diversity in wild and primitive cultivated barley in a center of diversity.

Genetics ◽

10.1093/genetics/119.4.981 ◽

1988 ◽

Vol 119 (4) ◽

pp. 981-990

Author(s):

S Jana ◽

L N Pietrzak

Keyword(s):

Genetic Diversity ◽

Eastern Mediterranean ◽

Hordeum Spontaneum ◽

Hordeum Vulgare L ◽

Closely Related Species ◽

Mediterranean Countries ◽

Isozyme Loci ◽

Cultivated Barley ◽

Multilocus Associations ◽

High Degree

Abstract Wild barley (Hordeum spontaneum K.) and indigenous primitive varieties of cultivated barley (Hordeum vulgare L.), collected from 43 locations in four eastern Mediterranean countries, Jordan, Syria, Turkey and Greece, were electrophoretically assayed for genetic diversity at 16 isozyme loci. Contrary to a common impression, cultivated barley populations were found to maintain a level of diversity similar to that in its wild progenitor species. Apportionment of overall diversity in the region showed that in cultivated barley within-populations diversity was of higher magnitude than the between-populations component. Neighboring populations of wild and cultivated barleys showed high degree of genetic identity. Groups of 3 or 4 isozyme loci were analyzed to detect associations among loci. Multilocus associations of varying order were detected for all three groups chosen for the analysis. Some of the association terms differed between the two species in the region. Although there was no clear evidence for decrease in diversity attributable to the domestication of barley in the region, there was an indication of different multilocus organizations in the two closely related species.

Download Full-text