Analysis of Genetic Variation Among Cowpea Aphid (Hemiptera: Aphididae) Populations Evidenced from Mitochondrial and Nuclear DNA Sequences

2019 ◽  
Vol 113 (3) ◽  
pp. 149-159
Author(s):  
Atsalek Rattanawannee ◽  
Kanyanat Wongsa ◽  
Orawan Duangphakdee

Abstract Aphis craccivora Koch (Hemiptera: Aphididae) or cowpea aphid is a polyphagous insect pest that feeds on a variety of leguminous plants. We determined the contribution of host-associated genetic differentiation on population structure using the sequence data generated from analysis of mitochondrial cytochrome b oxidase (Cytb) and nuclear elongation factor-1 alpha (EF1-alpha) of A. craccivora collected from cultivated yardlong bean [Vigna unguiculata (L.) Walp. ssp. sesquipedalis (L.) H. Ohashi.] (Fabales: Fabaceae) and winged bean [Psophocarpus tetragonolobus (L.) D.C.] (Fabales: Fabaceae). Phylogenetic and haplotype network analyses revealed no evidence of strong host plant or geographical clustering in both the mitochondrial and nuclear gene dataset. A moderate, low-magnitude genetic distance (FST) between host plants and geographical localities was found in this study. An analysis of molecular variance (AMOVA) revealed that host plant and geography do not influence the structure of genetic variation in A. craccivora populations. Genetic variation between host plants at a location and host plants among locations demonstrated no consistent result for population subdivision of A. craccivora. These results suggest that geographical location and host plants do not significantly influence the genetic structure of A. craccivora, and this might be due to their high reproductive (parthenogenesis) ability and high migration (airborne) between host plants and regions of the country.

2015 ◽  
Vol 2 (8) ◽  
pp. 140255 ◽  
Author(s):  
Claire C. Keely ◽  
Joshua M. Hale ◽  
Geoffrey W. Heard ◽  
Kirsten M. Parris ◽  
Joanna Sumner ◽  
...  

Two pervasive and fundamental impacts of urbanization are the loss and fragmentation of natural habitats. From a genetic perspective, these impacts manifest as reduced genetic diversity and ultimately reduced genetic viability. The growling grass frog ( Litoria raniformis ) is listed as vulnerable to extinction in Australia, and endangered in the state of Victoria. Remaining populations of this species in and around the city of Melbourne are threatened by habitat loss, degradation and fragmentation due to urban expansion. We used mitochondrial DNA (mtDNA) and microsatellites to study the genetic structure and diversity of L. raniformis across Melbourne's urban fringe, and also screened four nuclear gene regions (POMC, RAG-1, Rhod and CRYBA1). The mtDNA and nuclear DNA sequences revealed low levels of genetic diversity throughout remnant populations of L. raniformis . However, one of the four regions studied, Cardinia, exhibited relatively high genetic diversity and several unique haplotypes, suggesting this region should be recognized as a separate Management Unit. We discuss the implications of these results for the conservation of L. raniformis in urbanizing landscapes, particularly the potential risks and benefits of translocation, which remains a contentious management approach for this species.


IMA Fungus ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kai Wang ◽  
Timo Sipilä ◽  
Kirk Overmyer

AbstractProtomyces is an understudied genus of yeast-like fungi currently defined as phytopathogens of only Umbelliferae and Compositae. Species relationships and boundaries remain controversial and molecular data are lacking. Of the 82 named Protomyces, we found few recent studies and six available cultures. We previously isolated Protomyces strains from wild Arabidopsis thaliana, a member of Brassicaceae, a family distant from accepted Protomyces hosts. We previously sequenced the genomes of all available Protomyces species, and P. arabidopsidicola sp. nov. strain C29, from Arabidopsis. Phylogenomics suggests this new species occupied a unique position in the genus. Genomic, morphological, and physiological characteristics distinguished P. arabidopsidicola sp. nov. from other Protomyces. Nuclear gene phylogenetic marker analysis suggests actin1 gene DNA sequences could be used with nuclear ribosomal DNA internal transcribed spacer sequences for rapid identification of Protomyces species. Previous studies demonstrated P. arabidopsidicola sp. nov. could persist on the Arabidopsis phyllosphere and Protomyces sequences were discovered on Arabidopsis at multiple sites in different countries. We conclude that the strain C29 represents a novel Protomyces species and propose the name of P. arabidopsidicola sp. nov. Consequently, we propose that Protomyces is not strictly associated only with the previously recognized host plants.


Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1116
Author(s):  
Elkin Aguirre-Ramirez ◽  
Sandra Velasco-Cuervo ◽  
Nelson Toro-Perea

Anastrepha obliqua (Macquart) (Diptera: Tephritidae) is an important pest in the neotropical region. It is considered a polyphagous insect, meaning it infests plants of different taxonomic families and readily colonizes new host plants. The change to new hosts can lead to diversification and the formation of host races. Previous studies investigating the effect of host plants on population structure and selection in Anastrepha obliqua have focused on the use of data from the mitochondrial DNA sequence and microsatellite markers of nuclear DNA, and there are no analyses at the genomic level. To better understand this issue, we used a pooled restriction site-associated DNA sequencing (pooled RAD-seq) approach to assess genomic differentiation and population structure across sympatric populations of Anastrepha obliqua that infest three host plants—Spondias purpurea (red mombin), Mangifera indica (mango) of the family Anacardiaceae and Averrhoa carambola (carambola) of the family Oxalidaceae—in sympatric populations of the species Anastrepha obliqua of Inter-Andean Valley of the Cauca River in southwestern Colombia. Our results show genomic differentiation of populations from carambola compared to mango and red mombin populations, but the genetic structure was mainly established by geography rather than by the host plant. On the other hand, we identified 54 SNPs in 23 sequences significantly associated with the use of the host plant. Of these 23 sequences, we identified 17 candidate genes and nine protein families, of which four protein families are involved in the nutrition of these flies. Future studies should investigate the adaptive processes undergone by phytophagous insects in the Neotropics, using fruit flies as a model and state-of-the-art molecular tools.


2015 ◽  
Vol 97 (1) ◽  
pp. 187-199
Author(s):  
Robert D. Bradley ◽  
Matthew R. Mauldin

Abstract DNA sequences from the mitochondrial cytochrome- b gene were obtained from 41 specimens of Neotoma albigula from the southwestern United States and northwestern México. Phylogenetic analyses depicted that samples of N. a. melanura from southern Sonora and northern Sinaloa formed a clade separate from representatives of the other sampled subspecies of N. albigula ( albigula , laplataensis , mearnsi , seri , sheldoni , and venusta ). Genetic distances detected between these clades (7.41%) approached divergence levels reported for other sister species of woodrats and indicated that N. a. melanura is presumably a cryptic and genetically differentiated species relative to N . albigula . Analyses of DNA sequences from a nuclear gene (intron 2 of the alcohol dehydrogenase gene, Adh 1-I2) indicated that samples of N. a. melanura formed a separate, monophyletic clade relative to the remainder of N. albigula . Further, habitat, geographic distinctions, and morphological differences were apparent between members of the 2 clades. Together, those data support the elevation of N. a. melanura to species status. Secuencias de ADN del gen mitocondrial citocromo- b se obtuvieron de 41 especímenes de Neotoma albigula provenientes del suroeste de los Estados Unidos y del noroeste de México. Análisis filogenéticos revelaron que las muestras de N. a. melanura del sureste de Sonora y del norte de Sinaloa formaron un clado separado de especímenes que representan a las otras subspecies de N. albigula (albigula, laplataensis, mearnsi, seri, sheldoni , y venusta ). Las distancias genéticas detectadas entre estos clados (7.41%) se aproximan a los valores de divergencia reportados para otras especies de ratas magueyeras, indicando que N. a. melanura es presumiblemente una especie críptica y relativamente diferenciada genéticamente de N. albigula . Los análisis de secuencias de ADN de un gen nuclear (intron 2 del gen alcohol deshidrogenasa, Adh -I2) indicaron que las muestras de N. a. melanura formaron un clado separado relativamente a especímenes de N. albigula . Adicionalmente, hábitat, distinciones geográficas, y diferencias morfológicas fueron aparentes entre miembros de los dos clados. Todos estos datos soportan la elevación de N. a. melanura al estatus de especie.


2001 ◽  
Vol 22 (2) ◽  
pp. 235-242 ◽  
Author(s):  
J.C. Marshall ◽  
K.A. Crandall ◽  
D.J. Harris

AbstractSequences of the nuclear gene C-mos from 16 new species have been combined with previously published data to produce an analysis of squamate relationships using 56 taxa, considerably more than in previous analyses. Support for many nodes is greatly increased, thus producing a more robust assessment of relationships. Sampling was concentrated within the families Iguanidae and Lacertidae, both of which have poorly supported phylogenies based on mtDNA sequence data. Our analysis supports a robust estimate of relationships within the Iguanidae. Within the Lacertidae relationships are only partially well resolved, and this provides independent evidence for rapid speciation within this family.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tika B. Adhikari ◽  
Norman Muzhinji ◽  
Dennis Halterman ◽  
Frank J. Louws

AbstractEarly blight (EB) caused by Alternaria linariae or Alternaria solani and leaf blight (LB) caused by A. alternata are economically important diseases of tomato and potato. Little is known about the genetic diversity and population structure of these pathogens in the United States. A total of 214 isolates of A. alternata (n = 61), A. linariae (n = 96), and A. solani (n = 57) were collected from tomato and potato in North Carolina and Wisconsin and grouped into populations based on geographic locations and tomato varieties. We exploited 220 single nucleotide polymorphisms derived from DNA sequences of 10 microsatellite loci to analyse the population genetic structure between species and between populations within species and infer the mode of reproduction. High genetic variation and genotypic diversity were observed in all the populations analysed. The null hypothesis of the clonality test based on the index of association $$\left( {\overline{r}_{d} } \right)$$ r ¯ d was rejected, and equal frequencies of mating types under random mating were detected in some studied populations of Alternaria spp., suggesting that recombination can play an important role in the evolution of these pathogens. Most genetic differences were found between species, and the results showed three distinct genetic clusters corresponding to the three Alternaria spp. We found no evidence for clustering of geographic location populations or tomato variety populations. Analyses of molecular variance revealed high (> 85%) genetic variation within individuals in a population, confirming a lack of population subdivision within species. Alternaria linariae populations harboured more multilocus genotypes (MLGs) than A. alternata and A. solani populations and shared the same MLG between populations within a species, which was suggestive of gene flow and population expansion. Although both A. linariae and A. solani can cause EB on tomatoes and potatoes, these two species are genetically differentiated. Our results provide new insights into the evolution and structure of Alternaria spp. and can lead to new directions in optimizing management strategies to mitigate the impact of these pathogens on tomato and potato production in North Carolina and Wisconsin.


2021 ◽  
Author(s):  
Evandro Pires Lopes ◽  
Rui Freitas ◽  
Raquel Xavier ◽  
João Deus Soares ◽  
António M Santos

Abstract The snowflake coral Carijoa riisei is one of the most invasive and successfully adapting species in the coastal marine environment. This species can disperse through ballast waters or fouling on the hull of ships, which allows it to expand very quickly to areas where it is not native. Recently C. riisei was identified in the Porto Grande Bay in São Vicente island in Cabo Verde Islands. We analysed mitochondrial and nuclear DNA sequences from specimens collected at this locality to determine the potential origin of this invasion. Lack of genetic variation in both mitochondrial and nuclear genes suggest a very recent invasion (bottleneck effect) but did not permit to establish its origin with total confidence.


2018 ◽  
Vol 52 (6) ◽  
pp. 596-602
Author(s):  
Pimnapat Parimittr ◽  
Theeraphap Chareonviriyaphap ◽  
Michael J. Bangs ◽  
Uraiwan Arunyawat

2005 ◽  
Vol 272 (1581) ◽  
pp. 2577-2581 ◽  
Author(s):  
Philip A Astles ◽  
Allen J Moore ◽  
Richard F Preziosi

Indirect ecological effects (IEEs) are widespread and often as strong as the phenotypic effects arising from direct interactions in natural communities. Indirect effects can influence competitive interactions, and are thought to be important selective forces. However, the extent that selection arising from IEEs results in long-term evolutionary change depends on genetic variation underlying the phenotypic response—that is, a genotype-by-IEE interaction. We provide the first data on genetic variation in the response of traits to an IEE, and illustrate how such genetic variation might be detected and analysed. We used a model tri-trophic system to investigate the effect of host plants on two populations of predatory ladybirds through a clonal aphid herbivore. A split-family experimental design allowed us to estimate the effects of aphid host plant on ladybird traits (IEE) and the extent of genetic variation in ladybird predators for response to these effects (genotype-by-indirect environmental effect interaction). We found significant genetic variation in the response of ladybird phenotypes to the indirect effect of host plant of their aphid prey, demonstrating the potential for evolutionary responses to selection arising from the prey host.


2005 ◽  
Vol 26 (3) ◽  
pp. 271-285 ◽  
Author(s):  
D. James Harris ◽  
Nuno Ferrand ◽  
Eduardo Crespo ◽  
Raquel Godinho

AbstractPartial DNA sequences from three mitochondrial (cytochrome b, 12S rRNA and 16S rRNA) and two nuclear (β-fibrinogen intron 7 and C-mos) genes were used to estimate the phylogenetic relationships among all eight extant species of green lizards, Lacerta sensu stricto, and many currently recognized subspecies. All eight species form a monophyletic group. L. agilis, L. schreiberi and L. strigata are genetically well differentiated species. L. trilineata and L. pamphylica are not monophyletic units based on analyses of the β-fibrinogen intron 7. Lacerta media is closely related to some Lacerta trilineata. L. bilineata and L. viridis are closely related, and recognition of L. bilineata as a distinct species makes L. viridis paraphyletic also. For both L. bilineata and L. viridis, some subspecies appear to remain in their southern glacial refugia, while a single genetic entity shows successfully postglacial expansion. The topology derived from C-mos variation is concordant with that derived from mtDNA, with substitutions occurring at a similar rate to that of transversions in the rRNA genes. Although C-mos is typically used at deeper taxonomic levels it is also phylogenetically informative within green lizards. β-fibrinogen intron 7, typically used for assessing phylogenetic relationships among bird species, is a useful phylogenetic marker for reptiles also, showing considerable variation between species. There is not complete concordance between estimates of relationships derived from the mtDNA and nuclear markers, probably because rapid diversification led to incomplete lineage sorting in the green lizards. Introgression could also be occuring between some species.


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