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1.
Genes (Basel) ; 13(12)2022 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-36553462

RESUMO

The genus Argopistes (Chrysomelidae: Alticini) is the only group of flea beetles specialized in plant hosts in the family Oleaceae. In southern Africa, Argopistes are often found feeding on African Wild Olive (Olea europaea subsp. cuspidata) and European cultivated olive (O. e. subsp. europaea), and heavy infestations can be devastating to mature trees and compromise the development of young trees. Despite their negative agricultural impact, African Argopistes are an understudied group for which no genetic data were available. We assessed the species diversity of olive flea beetles in the Western Cape province of South Africa, the largest olive-producing region in sub-Saharan Africa, by collecting adult specimens on wild and cultivated olive trees between 2015 and 2017. Argopistes sexvittatus Bryant, 1922 (n = 289) dominated at all sampling sites, and Argopistes capensis Bryant, 1944 (n = 2) was found only once. Argopistes oleae Bryant, 1922, a third species previously reported in the region, was not found. The complete mitogenomes of one A. capensis and two A. sexvittatus (striped and black morphotypes) individuals were sequenced for phylogenetic reconstruction in the context of other 64 species. The two olive flea beetle species form a monophyletic clade with other Argopistes, supporting the hypothesis that the exclusive feeding habit on Oleaceae is an evolutionary adaptation in this genus.


Assuntos
Besouros , Olea , Oleaceae , Sifonápteros , Animais , Filogenia , Olea/genética , Besouros/genética , Evolução Biológica , Oleaceae/genética
2.
Insects ; 13(7)2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35886783

RESUMO

Anchonocranus oleae Marshall (Coleoptera: Curculionidae) is a seed-feeding weevil native to southern Africa; its larvae are known to develop in the fruits of the African Wild Olive and, more rarely, cultivated olives. The species has been mainly found in the Western Cape province of South Africa, but it has remained in relative obscurity because it does not seem to represent a current threat to commercial olive production. As part of an ongoing effort to produce baseline genetic data for olive-associated entomofauna in South Africa, we generated reference DNA barcodes for A. oleae collected from wild and cultivated olives and sequenced its mitogenome for assessment of the phylogenetic position of the species in the family Curculionidae. The mitochondrial phylogeny estimate indicated that A. oleae shares a common ancestor with Elaidobius (tribe Derelomini), but a definite and close relationship to this tribe and the precise tribal placement of A. oleae in the subfamily Curculioninae could not be inferred due to the lack of representative mitogenomes of other relevant curculionine tribes and genera. This study will assist future work on the DNA-based species identification, genetic diversity, and phylogenetic position of the genus Anchonocranus and related taxa.

3.
Ecol Evol ; 12(7): e9090, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35866018

RESUMO

The Asian citrus psyllid (Diaphorina citri Kuwayama) is a key pest of Citrus sp. worldwide, as it acts as a vector for Candidatus Liberibacter asiaticus, the bacterial pathogen that causes citrus Huanglongbing. Diaphorina citri has been reported in Kenya, Tanzania, and more recently in Ethiopia. This study assessed the genetic diversity and phylogeographic structure of the pest to gain insights into the potential sources of its introduction into Africa. Population structure and differentiation of D. citri populations from China, Ethiopia, Kenya, Tanzania, and the USA were assessed using 10 microsatellite loci. Additionally, five new complete mitogenomes of D. citri collected in China, Ethiopia, Kenya, Tanzania, and the USA were analyzed in the context of publicly available sequences. Genotype data grouped the D. citri populations from Kenya and Tanzania in one cluster, and those from Ethiopia formed a separate cluster. The two genetic clusters inferred from genotype data were congruent with mitochondrial sequence data. The mitogenomes from Kenya/Tanzania/China had 99.0% similarity, and the Ethiopia/USA had 99.9% similarity. In conclusion, D. citri populations in eastern Africa have different sources, as the Kenyan and Tanzanian populations probably originated from southeastern Asia, while the Ethiopian population most probably originated from the Americas.

4.
PeerJ ; 10: e13275, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35462770

RESUMO

African Saturniidae (Lepidoptera) include numerous species consumed at the caterpillar stage throughout the continent, and their importance to local communities as a source of nutrition and seasonal income cannot be overestimated. However, baseline genetic data with utility for the characterization of their diversity, phylogeography and phylogenetic relationships have remained scarce compared to their Asian counterparts. To bridge this gap, we sequenced the mitochondrial genomes of 12 species found in southern Africa for comparative mitogenomics and phylogenetic reconstruction of the family, including the first representatives of the tribes Eochroini and Micragonini. Mitochondrial gene content and organization were conserved across all Saturniidae included in the analyses. The phylogenetic positions of the 12 species were assessed in the context of publicly available mitogenomes using Bayesian inference and maximum likelihood (ML) methods. The monophyly of the tribes Saturniini, Attacini, Bunaeini and Micragonini, the sister relationship between Saturniini and Attacini, and the placement of Eochroa trimenii and Rhodinia fugax in the tribes Eochroini and Attacini, respectively, were strongly supported. These results contribute to significantly expanding genetic data available for African Saturniidae and allow for the development of new mitochondrial markers in future studies.


Assuntos
Lepidópteros , Manduca , Animais , Lepidópteros/genética , Filogenia , Teorema de Bayes , Sequência de Bases , Manduca/genética
5.
Insects ; 12(9)2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34564270

RESUMO

Olive lace bugs (Hemiptera: Tingidae) are small sap-sucking insects that feed on wild and cultivated Olea europaea. The diversity of olive lace bug species in South Africa, the most important olive producer on the continent, has been incompletely surveyed. Adult specimens were collected in the Western Cape province for morphological and DNA-based species identification, and sequencing of complete mitogenomes. Cysteochila lineata, Plerochila australis, Neoplerochila paliatseasi and Neoplerochila sp. were found at 12 sites. Intra- and interspecific genetic divergences and phylogenetic clustering in 30 species in 18 genera of Tingidae using new and publicly available DNA barcodes showed high levels of congruity between taxonomic and genetic data. The phylogenetic position of the four species found in South Africa was inferred using new and available mitogenomes of Tingidae. Notably, olive lace bugs formed a cluster of closely related species. However, Cysteochila was non-monophyletic as C. lineata was recovered as a sister species to P. australis whereas Cysteochila chiniana, the other representative of the genus, was grouped with Trachypeplus jacobsoni and Tingis cardui in a different cluster. This result suggests that feeding on O. europaea may have a common origin in Tingidae and warrants future research on potential evolutionary adaptations of olive lace bugs to this plant host.

6.
Insects ; 12(6)2021 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-34204854

RESUMO

Macrotermes termites play important ecological roles and are consumed by many communities as a delicacy and dietary complement throughout Africa. However, lack of reliable morphological characters has hampered studies of Macrotermes diversity in a wide range of scientific fields including ecology, phylogenetics and food science. In order to place our preliminary assessment of the diversity of Macrotermes in South Africa in context, we analysed a comprehensive dataset of COI sequences for African species including new and publicly available data. Phylogenetic reconstruction and estimates of genetic divergence showed a high level of incongruity between species names and genetic groups, as well as several instances of cryptic diversity. We identified three main clades and 17 genetic groups in the dataset. We propose that this structure be used as a background for future surveys of Macrotermes diversity in Africa, thus mitigating the negative impact of the present taxonomic uncertainties in the genus. The new specimens collected in Limpopo fell into four distinct genetic groups, suggesting that the region harbours remarkable Macrotermes diversity relative to other African regions surveyed in previous studies. This work shows that African Macrotermes have been understudied across the continent, and that the genus contains cryptic diversity undetectable by classic taxonomy. Furthermore, these results may inform future taxonomic revisions in Macrotermes, thus contributing to advances in termitology.

7.
Genetica ; 149(1): 1-19, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33515402

RESUMO

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a central role in cholesterol homeostasis in humans as a major regulator of LDLR levels. PCSK9 is an intriguing protease in that it does not act by proteolysis but by preventing LDLR recirculation from endosomes to the plasma membrane. This, and the inexistence of any other proteolytic substrate but itself could suggest that PCSK9 is an exquisite example of evolutionary fine-tuning. However, the gene has been lost in several mammalian species, and null alleles are present (albeit at low frequencies) in some human populations without apparently deleterious health effects, raising the possibility that the PCSK9 may have become dispensable in the mammalian lineage. To address this issue, we systematically recovered, assembled, corrected, annotated and analysed publicly available PCSK9 sequences for 420 eutherian species to determine the distribution, frequencies, mechanisms and timing of PCSK9 pseudogenization events, as well as the evolutionary pressures underlying the preservation or loss of the gene. We found a dramatic difference in the patterns of PCSK9 retention and loss between Euarchontoglires-where there is strong pressure for gene preservation-and Laurasiatheria, where multiple independent events have led to PCSK9 loss in most species. These results suggest that there is a fundamental difference in the regulation of cholesterol metabolism between Euarchontoglires and Laurasiatheria, which in turn has important implications for the use of Laurasiatheria species (e.g. pigs) as animal models of human cholesterol-related diseases.


Assuntos
Colesterol/genética , Evolução Molecular , Pró-Proteína Convertase 9/genética , Receptores de LDL/genética , Animais , Colesterol/metabolismo , Eutérios/genética , Variação Genética/genética , Humanos , Filogenia , Pseudogenes/genética , Suínos/genética
8.
Insects ; 11(12)2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33276418

RESUMO

The family Braconidae consists mostly of specialized parasitoids, some of which hold potential in biocontrol of agricultural pests. Psyttalia concolor, Psyttalia humilis and Psyttalia lounsburyi are parasitoids associated with Bactrocera oleae, a major pest of cultivated olives. The native range of Psyttalia concolor is the Mediterranean, and P. humilis and P. lounsburyi are native to sub-Saharan Africa. This study reports the mitochondrial genomes of the three species, thus laying the foundation for mitogenomic analyses in the genus Psyttalia. Comparative mitogenomics within Braconidae showed a novel gene arrangement in Psyttalia in involving translocation and inversion of transfer RNA genes. The placement of Psyttalia in the subfamily Opiinae was well-supported, and the divergence between Psyttalia and its closest relative (Diachasmimorpha longicaudata) was at ~55 MYA [95% highest posterior density (HPD): 34-83 MYA]. Psyttalia lounsburyi occupied the most basal position among the three Psyttalia, having diverged from the other two species ~11 MYA (95% HPD: 6-17 MYA). Psyttalia concolor and P. humilis were recovered as sister species diverged at ~2 MYA (95% HPD: 1.1-3.6 MYA). This phylogeny combining new sequences and a set of 31 other cyclostomes and non-cyclostomes highlights the importance of a comprehensive taxonomic coverage of Braconidae mitogenomes to overcome the lack of robustness in the placement of several subfamilies.

9.
Sci Rep ; 10(1): 20204, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33188268

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

10.
Sci Rep ; 10(1): 8893, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32483282

RESUMO

Trioza erytreae is the main vector for 'Candidatus Liberibacter africanus', the causative agent of African Citrus Greening disease. The insect is widespread in Africa, and has recently disseminated to Southwestern Europe. This study aimed at generating reference mitogenome sequences for T. erytreae, as a background for future genetic diversity surveys. Complete mitochondrial sequences of three specimens collected in Ethiopia, Uganda and South Africa were recovered using Ion Torrent technology. The mitogenomes of T. erytreae from Uganda and Ethiopia were highly similar, and distinct from that found in South Africa. The phylogeographic structure of T. erytreae was assessed using genetic clustering and pairwise distances, based on a dataset of public COI sequences recorded as T. erytreae. The dataset revealed ten haplotypes with strong phylogeographic structure in Africa and Europe. Three haplotypes found in Kenya on Clausena anisata belonged to pairs separated by distances as high as 11.2%, and were basal to all other sequences. These results indicate that not all sequences identified as T. erytreae belong to the same species, and that some degree of specificity with different plant hosts is likely to exist. This study provides new baseline information on the diversity of T. erytreae, with potential implications for the epidemiology of African Citrus Greening disease.


Assuntos
Citrus/parasitologia , Variação Genética , Hemípteros/classificação , Mitocôndrias/genética , Sequenciamento Completo do Genoma/veterinária , Animais , Etiópia , Europa (Continente) , Tamanho do Genoma , Genoma Mitocondrial , Haplótipos , Hemípteros/genética , Quênia , Filogenia , Filogeografia , África do Sul , Uganda
11.
J Econ Entomol ; 113(4): 1640-1647, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32533151

RESUMO

Diaphorina citri Kuwayama, also known as the Asian citrus psyllid, is a pest of citrus known for its transmission of Candidatus Liberibacter asiaticus (Ca. L. asiaticus), the causal bacterium of Huanglongbing. The African citrus triozid Trioza erytreae (Del Guercio) (Hemiptera: Triozidae) has been the putative vector of Candidatus Liberibacter africanus (Ca. L. africanus) which causes the African citrus greening disease, until the recent detection of D. citri on the continent. Following reports of D. citri in Kenya and Tanzania, we surveyed citrus plants to establish the presence/absence of D. citri in Ethiopia in citrus-growing regions ranging from 900 to 2,460 m above sea level (masl). Diaphorina citri adults were detected in five of the surveyed sites in Ethiopia. Adult insects encountered were collected using an aspirator and stored in 97% ethanol. The mitochondrial cytochrome oxidase 1 (mt COI) gene of the collected insects was amplified using LepF1/LepR1 primers, and sequences obtained showed low variation, which fell within the acceptable range of species. BLAST was used to query the sequences obtained, and all the sequences linked to D. citri accessions that are available in GenBank. The analysis of the sequences revealed a new haplotype of the species that differs from haplotypes previously reported. Phylogenetic relationships of our samples and other D. citri reference sequences was inferred using the Maximum-likelihood method. Monophyly was observed between the samples and the publicly available sequences from global accessions. This is the first report of the presence of D. citri in Ethiopia.


Assuntos
Citrus , Hemípteros , Rhizobiaceae , Animais , Proliferação de Células , Etiópia , Haplótipos , Hemípteros/genética , Quênia , Filogenia , Doenças das Plantas , Tanzânia
12.
PLoS One ; 15(6): e0235348, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32589643

RESUMO

The Asian citrus psyllid (Diaphorina citri) is a key pest of Citrus spp. worldwide, as it acts as a vector for "Candidatus Liberibacter asiaticus (Las)", the bacterial pathogen associated with the destructive Huanglongbing (HLB) disease. Recent detection of D. citri in Africa and reports of Las-associated HLB in Ethiopia suggest that the citrus industry on the continent is under imminent threat. Endosymbionts and gut bacteria play key roles in the biology of arthropods, especially with regards to vector-pathogen interactions and resistance to antibiotics. Thus, we aim to profile the bacterial genera and to identify antibiotic resistance genes within the microbiome of different populations worldwide of D. citri. The metagenome of D. citri was sequenced using the Oxford Nanopore full-length 16S metagenomics protocol, and the "What's in my pot" (WIMP) analysis pipeline. Microbial diversity within and between D. citri populations was assessed, and antibiotic resistance genes were identified using the WIMP-ARMA workflow. The most abundant genera were key endosymbionts of D. citri ("Candidatus Carsonella", "Candidatus Profftella", and Wolbachia). The Shannon diversity index showed that D. citri from Tanzania had the highest diversity of bacterial genera (1.92), and D. citri from China had the lowest (1.34). The Bray-Curtis dissimilarity showed that China and Kenya represented the most diverged populations, while the populations from Kenya and Tanzania were the least diverged. The WIMP-ARMA analyses generated 48 CARD genes from 13 bacterial species in each of the populations. Spectinomycin resistance genes were the most frequently found, with an average of 65.98% in all the populations. These findings add to the knowledge on the diversity of the African D. citri populations and the probable introduction source of the psyllid in these African countries.


Assuntos
Biodiversidade , Hemípteros/microbiologia , Microbiota , Filogenia , Animais , China , Resistência Microbiana a Medicamentos/genética , Insetos Vetores/microbiologia , Quênia , Microbiota/efeitos dos fármacos , Microbiota/genética , Doenças das Plantas/microbiologia , Análise de Sequência , Simbiose , Tanzânia
13.
Zootaxa ; 4722(5): zootaxa.4722.5.3, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-32230605

RESUMO

Olive lace bugs are small phytophagous Hemipteran insects known to cause agricultural losses in olive production in South Africa. Plerochila australis (Distant, 1904) has been reported as the species responsible for damage to olive trees; however, the diversity of olive lace bug species in the region has lacked attention. Adult olive lace bugs were collected incidentally from wild and cultivated olive trees in the Western Cape Province, and identified as P. australis and Neoplerochila paliatseasi (Rodrigues, 1981). The complete mitochondrial genome of a representative specimen of N. paliatseasi was sequenced, and used for comparative mitogenomics and phylogenetic reconstruction within the family. Furthermore, the value of DNA barcodes for species identification in Tingidae was assessed using genetic clustering and estimates of genetic divergence. The patterns of genetic clustering and genetic divergence of COI sequences supported the morphological identification of N. paliatseasi, and the utility of DNA barcoding methods in Tingidae. The complete mitogenome sequence had the typical Metazoan gene content and order, including 13 PCGs, 22 tRNAs, two rRNAs, and an AT-rich non-coding region. A+T content was high, as commonly found in Tingidae. The phylogenetic reconstruction recovered Agramma hupehanum (Drake Maa 1954) as basal to Tingini, and as a sister species to N. paliatseasi. Stephanitis Stål 1873 and Corythucha Stål 1873 were monophyletic, but Metasalis populi (Takeya 1932) was not recovered as sister to Tingis cardui (Linnaeus 1746), as expected. The mitochondrial phylogeny of the family Tingidae has been recovered inconsistently across different studies, possibly due to sequence heterogeneity and high mutation rates. Species diversity of olive lace bugs in South Africa was previously underestimated. The presence of P. australis was confirmed in both wild and cultivated olives, and N. paliatseasi is reported in cultivated olives for the first time. These results warrant further investigation on the diversity and distribution of olive lace bugs in the Western Cape to inform pest control strategies.


Assuntos
Genoma Mitocondrial , Hemípteros , Heterópteros , Animais , Filogenia , África do Sul
14.
Sci Rep ; 10(1): 3919, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32127552

RESUMO

Huanglongbing (HLB) is a serious disease of Citrus sp. worldwide. In Africa and the Mascarene Islands, a similar disease is known as African citrus greening (ACG) and is associated with the bacterium Candidatus Liberibacter africanus (Laf). In recent years, Candidatus Liberibacter asiaticus (Las) associated with the severe HLB has been reported in Ethiopia. Thus, we aimed to identify the Liberibacter species affecting citrus, the associated vectors in Eastern Africa and their ecological distribution. We assessed the presence of generic Liberibacter in symptomatic leaf samples by quantitative PCR. Subsequently, we sequenced the 50 S ribosomal protein L10 (rplJ) gene region in samples positive for Liberibacters and identified the species by comparison with public sequence data using phylogenetic reconstruction and genetic distances. We detected generic Liberibacter in 26%, 21% and 66% of plants tested from Uganda, Ethiopia and Kenya, respectively. The rplJ sequences revealed the most prevalent Liberibacters in Uganda and Ethiopia were LafCl (22%) and Las (17%), respectively. We detected Las in Kenya for the first time from three sites in the coastal region. Finally, we modelled the potential habitat suitability of Las in Eastern Africa using MaxEnt. The projection showed large areas of suitability for the pathogen in the three countries surveyed. Moreover, the potential distribution in Eastern Africa covered important citrus-producing parts of Ethiopia, Kenya, Uganda and Tanzania, and included regions where the disease has not been reported. These findings will guide in the development of an integrated pest management strategy to ACG/HLB management in Africa.


Assuntos
Helicobacter heilmannii/fisiologia , Doenças das Plantas/microbiologia , Citrus/microbiologia , Helicobacter heilmannii/genética , Helicobacter heilmannii/isolamento & purificação , Quênia , Análise de Sequência
15.
Int J Biol Macromol ; 144: 632-642, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31830455

RESUMO

Mopane worms are the vernacular designation for the edible caterpillars of the African emperor moths Gonimbrasia belina and Gynanisa maja. Both species, particularly G. belina, are widely harvested in Southern Africa, and their populations are declining. Despite their commercial, nutritional, and cultural importance, their genetic data are currently unavailable. We sequenced two complete mitogenomes from each species using Ion Torrent technology, and identified informative markers in the complete mitogenomes of the two species for use in future studies. Comparing the conspecific mitogenomes allowed the identification of regions with high nucleotide diversity in ATP6, ND1, ND4, ND5, ND6, and CYTB genes. The final panels of markers will allow for the survey of 3117 bp in G. belina, and 3990 bp in Gy. maja. Phylogenetic reconstruction within the family Saturniidae recovered the tribe Bunaeini as monophyletic and basal to Saturniidae, and the tribe Attacini as a monophyletic clade nested within the tribe Saturniini. The G. belina and Gy. maja mitogenomes are the first representatives of African Saturniidae, a taxonomic group with relevance as a food resource on the continent. This study represents the first step towards assessing the genetic diversity, population structure, and phylogeography of African edible caterpillars.


Assuntos
Genoma de Inseto/genética , Genoma Mitocondrial/genética , Larva/genética , África Austral , Animais , Sequência de Bases , Mapeamento Cromossômico , Edição de Genes , Genes Mitocondriais/genética , Código Genético , Sequenciamento de Nucleotídeos em Larga Escala , Mariposas , Conformação de Ácido Nucleico , Filogenia
16.
PLoS One ; 14(12): e0226505, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31869351

RESUMO

Nile crocodiles are apex predators widely distributed in sub-Saharan Africa that have been viewed and managed as a single species. A complex picture of broad and fine-scale phylogeographic patterns that includes the recognition of two species (Crocodylus niloticus and Crocodylus suchus), and the structuring of populations according to river basins has started to emerge. However, previous studies surveyed a limited number of samples and geographical regions, and large areas of the continent remained unstudied. This work aimed at a fine scale portrait of Nile crocodile populations at the fringes of their geographic distribution in southern Africa. Wild and captive individuals were sampled across four major river systems (Okavango, Lower Kunene, Lower Shire and Limpopo) and the KwaZulu-Natal region. A multi-marker approach was used to infer phylogeographic and genetic diversity patterns, including new and public mitochondrial data, and a panel of 11 nuclear microsatellites. All individuals belonged to a phylogenetic clade previously associated with the C. niloticus species, thus suggesting the absence of C. suchus in southern Africa. The distribution of mitochondrial haplotypes indicated ancestral genetic connectivity across large areas, with loss of diversity along the north-south axis. Genetic variation partitioned the populations primarily into western and eastern regions of southern Africa, and secondarily into the major river systems. Populations were partitioned into five main groups corresponding to the Lower Kunene, the Okavango, the Lower Shire, and the Limpopo rivers, and the KwaZulu-Natal coastal region. All groups show evidence of recent bottlenecks and small effective population sizes. Long-term genetic diversity is likely to be compromised, raising conservation concern. These results emphasize the need for local genetic assessment of wild populations of Nile crocodiles to inform strategies for management of the species in southern Africa.


Assuntos
Jacarés e Crocodilos/classificação , Jacarés e Crocodilos/genética , Variação Genética , África Austral/epidemiologia , Jacarés e Crocodilos/crescimento & desenvolvimento , Animais , DNA Mitocondrial/análise , DNA Mitocondrial/genética , Demografia , Haplótipos , Repetições de Microssatélites/genética , Filogenia , Filogeografia/estatística & dados numéricos , Densidade Demográfica , Rios
17.
Genome ; 62(3): 183-199, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30365918

RESUMO

Wild and cultivated olives harbor and share a diversity of insects, some of which are considered agricultural pests, such as the olive fruit fly. The assemblage of olive-associated parasitoids and seed wasps is rich and specialized in sub-Saharan Africa, with native species possibly coevolving with their hosts. Although historical entomological surveys reported on the diversity of olive wasp species in the Western Cape Province of South Africa, no comprehensive study has been performed in the region in the molecular era. In this study, a dual approach combining morphological and DNA-based methods was used for the identification of adult specimens reared from olive fruits. Four species of Braconidae and six species of Chalcidoidea were identified, and DNA barcoding methodologies were used to investigate conspecificity among individuals, based on randomly selected representative specimens. Morphological identifications were congruent with DNA data, as NJ and ML trees correctly placed the sequences for each species either at the genus or species level, depending on the available taxa coverage, and genetic distances strongly supported conspecificity. No clear evidence of cryptic diversity was found. Overall seed infestation and parasitism rates were higher in wild olives compared to cultivated olives, and highest for Eupelmus spermophilus and Utetes africanus. These results can be used for early DNA-based detection of wasp larvae in olives and to further investigate the biology and ecology of these species.


Assuntos
Biodiversidade , Código de Barras de DNA Taxonômico/métodos , DNA/genética , Olea/parasitologia , Vespas/classificação , Vespas/genética , Animais , DNA/análise , Olea/genética , Filogenia , África do Sul
18.
Int J Biol Macromol ; 126: 130-140, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30584936

RESUMO

Bactrocera biguttula is an African olive fruit fly that does not attack cultivated olives but rather develops in the fruits of wild species of Olea and Noronhia. The complete mitochondrial genome of an individual specimen was characterized in comparison to other Bactrocera. The phylogenetic relationships of B. biguttula with other Dacini were investigated, with special focus on B. oleae, an agricultural pest known to attack cultivated and wild olives. The sequence had a total length of 15,829 bp, and included the typical features of insect mitogenomes, similarly to the other Bactrocera analysed. Start codons included ATG, ATC, ATT, and TCG (in COI). The majority of stop codons (TAA) were fully encoded, whereas in some cases only TA or T were present. The complete sequence was biased towards A + T, with a positive AT-skew and a negative GC-skew. The predicted cloverleaf structure of tRNASer1 showed absence of the DHU arm, a common feature in insects and other Metazoans. Phylogenetic reconstruction showed that B. biguttula and B. oleae are sister species, having diverged from a common ancestor < 10 Myr ago. This result warrants future genomic comparisons between these two closely related species for investigating the specific adaptations to the different hosts.


Assuntos
Genoma Mitocondrial , Filogenia , Tephritidae/classificação , Tephritidae/genética , Animais , Composição de Bases/genética , Teorema de Bayes , Códon/genética , DNA Circular/genética , Funções Verossimilhança , Conformação de Ácido Nucleico , Fases de Leitura Aberta/genética , RNA de Transferência/genética , Tephritidae/anatomia & histologia
19.
Mol Cytogenet ; 11: 30, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29760780

RESUMO

BACKGROUND: In countries where comparative genomic hybridization arrays (aCGH) and next generation sequencing are not widely available due to accessibility and economic constraints, conventional 400-500-band karyotyping is the first-line choice for the etiological diagnosis of patients with congenital malformations and intellectual disability. Conventional karyotype analysis can rule out chromosomal alterations greater than 10 Mb. However, some large structural abnormalities, such as derivative chromosomes, may go undetected when the analysis is performed at less than a 550-band resolution and the size and banding pattern of the interchanged segments are similar. Derivatives frequently originate from inter-chromosomal exchanges and sometimes are inherited from a parent who carries a reciprocal translocation. CASE PRESENTATION: We present two cases with derivative chromosomes involving a 9.1 Mb 5p deletion/14.8 Mb 10p duplication in the first patient and a 19.9 Mb 5p deletion/ 18.5 Mb 9p duplication in the second patient. These long chromosomal imbalances were ascertained by aCGH but not by conventional cytogenetics. Both patients presented with a deletion of the Cri du chat syndrome region and a duplication of another genomic region. Each patient had a unique clinical picture, and although they presented some features of Cri du chat syndrome, the phenotype did not conclusively point towards this diagnosis, although a chromosomopathy was suspected. CONCLUSIONS: These cases highlight the fundamental role of the clinical suspicion in guiding the approach for the etiological diagnosis of patients. Molecular cytogenetics techniques, such as aCGH, should be considered when the clinician suspects the presence of a chromosomal imbalance in spite of a normal karyotype.

20.
Mitochondrial DNA A DNA Mapp Seq Anal ; 27(3): 2108-9, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-25423526

RESUMO

Prays oleae is one of the most important olive tree pests and a species of interest in evolutionary studies, as it belongs to one of the oldest extant superfamilies of Ditrysian Lepidoptera. We determined its mitogenome sequence, and found it has common features for Lepidoptera, e.g. an >80% A + T content, an apparent CGA start codon for COX1 and an ATAGA(T)n motif in the control region, which also contains several copies of a 163-164 bp repeat. Importantly, the mitogenome displays the Met-Ile-Gln tRNA gene order typical of Ditrysia, consistent with the hypothesis that this is a synapomorphy of that clade.


Assuntos
Genoma Mitocondrial , Lepidópteros/genética , Animais , Composição de Bases/genética , Pareamento de Bases/genética , Sequência de Bases , DNA Mitocondrial/genética
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