Francisco Panzera | Facultad de Ciencias, Universidad e la República (original) (raw)

Papers by Francisco Panzera

Comparative Cytogenetics, Dec 18, 2014

Species of infraorder Cimicomorpha of Heteroptera exhibit holokinetic chromosomes with inverted m... more Species of infraorder Cimicomorpha of Heteroptera exhibit holokinetic chromosomes with inverted meiosis for sex chromosomes and high variation in chromosome number. The family Reduviidae, which belongs to this infraorder, is also recognized by high variability of heterochromatic bands and chromosome location of 18S rDNA loci. We studied here five species of Reduviidae (Harpactorinae) with predator habit, which are especially interesting because individuals are found solitary and dispersed in nature. These species showed striking variation in chromosome number (including sex chromosome systems), inter-chromosomal asymmetry, different number and chromosome location of 18S rDNA loci, dissimilar location and quantity of autosomal C-heterochromatin, and different types of repetitive DNA by fluorochrome banding, probably associated with occurrence of different chromosome rearrangements. Terminal chromosome location of C-heterochromatin seems to reinforce the model of equilocal dispersion of repetitive DNA families based in the "bouquet configuration".

Medical and Veterinary Entomology, 1998

Among collections of Triatoina spiitolai from various sites in northern Chile, adults from coasta... more Among collections of Triatoina spiitolai from various sites in northern Chile, adults from coastal populations are invariably wingless, whereas inland populations show balanced alary polymorphism between wingless females and males that are either winged or wingless. Laboratory crosses showed that male offspring from normal-winged parents were always winged (88% long-winged) and those from long-winged male parents were all long-winged. The male offspring from wingless males always included winged males: 11/33 = 33%, of which 8/11 = 73% were longwinged. An X-linked mutation is proposed to inhibit wing development. Field studies of population demography indicate that male alary polymorphism is advantageous in the desert environment of northern Chile.

Zootaxa, May 2, 2016

Triatoma bahiensis Sherlock &... more Triatoma bahiensis Sherlock & Serafim, 1967, T. lenti Sherlock & Serafim, 1967, and T. pessoai Sherlock & Serafim, 1967 were described based on material collected in the Brazilian state of Bahia. These species were later included in the T. brasiliensis complex based on their geographic distribution. Triatoma bahiensis and T. pessoai were subsequently synonymized with T. lenti. However, the phylogenetic position of T. lenti within the T. brasiliensis complex has remained doubtful. This study aims to assess the taxonomic status of T. bahiensis and to infer the phylogenetic relationships between T. lenti, T. bahiensis and the other members of the T. brasiliensis species complex. The identities of the species in concern were confirmed by comparisons with high resolution photos of the respective type materials; lectotypes are designated for T. pessoai and T. bahiensis. Morphological, morphometric, molecular, and cytogenetic approaches as well as experimental crosses were used. The low viability of experimental crosses combined with morphological and morphometric data allow the differentiation of T. bahiensis and T. lenti. Pairwise cyt b sequence divergence between T. lenti and T. bahiensis was 2.5%. Cytogenetic and molecular analyses grouped T. lenti and T. bahiensis as members of the T. brasiliensis complex. These results revalidate the specific status of T. bahiensis.

Transactions of The Royal Society of Tropical Medicine and Hygiene, Sep 1, 1991

Transactions of the Royal Society of Tropical Medicine and Hygiene, Volume 85, Issue 5, Pages 679... more Transactions of the Royal Society of Tropical Medicine and Hygiene, Volume 85, Issue 5, Pages 679-680, September 1991, Authors:JP Dujardin; MT Garcia-Zapata; J. Jurberg; P. Roelants; L. Cardozo; F. Panzera; JCP Dias; CJ Schofield.

We analyzed the main karyologic changes that have occurred during the dispersal of Triatoma infes... more We analyzed the main karyologic changes that have occurred during the dispersal of Triatoma infestans, the main vector of Chagas disease. We identified two allopatric groups, named Andean and non-Andean. The Andean specimens present C-heterochromatic blocks in most of their 22 chromosomes, whereas non-Andean specimens have only 4-7 autosomes with C-banding. These heterochromatin differences are the likely cause of a striking DNA content variation (approximately 30%) between Andean and non-Andean insects. Our study, together with previous historical and genetic data, suggests that T. infestans was originally a sylvatic species, with large quantities of DNA and heterochromatin, inhabiting the Andean region of Bolivia. However, the spread of domestic T. infestans throughout the non-Andean regions only involved insects with an important reduction of heterochromatin and DNA amounts. We propose that heterochromatin and DNA variation mainly reflected adaptive genomic changes that contribute to the ability of T. infestans to survive, reproduce, and disperse in different environments. A merican trypanosomiasis or Chagas disease is well recognized as the most serious human parasitic disease of the Americas in terms of its social and economic impact (1). This disease is caused by the flagellate protozoan Trypanosoma cruzi, and it is transmitted by bloodsucking insects of the subfamily Triatominae (Hemiptera, Reduviidae). There is no vaccine against T. cruzi; therefore, disease control relies on eliminating domestic vector populations by spraying infested houses with residual insecticides. The epidemiologic importance of Chagas disease vectors largely depends on the vectors' spreading ability and adaptation to domestic habitats. Therefore, studies on the changes that have taken place in such domestication and geographic expansion may contribute to understanding the basic process by which some species of Triatominae invade new habitats and colonize human habitations. These analyses are fundamental in the design of control campaigns because their results will help determine the most appropiate strategy for insecticide application. Knowledge of the genetic structure of insect populations (including the evaluation of gene flow between domestic and sylvatic populations), as well as their domestication and spreading capabilities, are essential tools for effective vector control (2). Triatoma infestans represents the best example of spreading and adaptation to domicilies observed in a triatomine species. This species is the main and widespread vector in South America, responsible for about half of the 12 million cases of Chagas disease reported worldwide. Although its distribution is now being substantially reduced by large-scale control interventions within the Southern Cone Initiative, launched in 1991 by six South American countries (1), its distribution in the mid-1980s was very wide, including vast regions of Argentina, Bolivia, Brazil, Chile, Paraguay, southern Peru, and Uruguay (Figure 1). T. infestans is found almost exclusively in domestic and peridomestic environments, occupying cracks and crevices in rural dwellings and domestic animal enclosures. The presence of this species in sylvatic habitats (rock piles in association with wild guinea pigs) has only been confirmed in the Andean valleys of Cochabamba and Sucre in Bolivia (3-5). This finding, together with historical reconstruction (6) and genetic analyses (7), suggests that central Bolivia may be the site of origin and dispersal of T. infestans throughout South America. One important approach used to establish genetic variation in T. infestans is cytogenetic analysis. The diploid chromosome number of T. infestans is 22, including 10 pairs of autosomes and 1 pair of sex chromosomes (XY in males, XX in females) (8). The three large autosomal pairs and the Y chromosome present C-heterochromatic blocks 438

... Document details. Title Sex chromosomes of Neotropical Coleoptera from Uruguay. Authors Posti... more ... Document details. Title Sex chromosomes of Neotropical Coleoptera from Uruguay. Authors Postiglioni, A.; Mazzella, MC; Panzera, F.; Silva, A. da; Ponce de León, RP; Kvasina, L.; Scvortzoff, E. Conference paper; Journal article Nucleus (Calcutta) 1990 Vol. 33 No. 1-2 pp. ...

Infection, Genetics and Evolution, Nov 1, 2016

Hematophagous insects of the subfamily Triatominae include several species with a large variety o... more Hematophagous insects of the subfamily Triatominae include several species with a large variety of shapes, behavior and distribution. They have great epidemiological importance since most of them transmit the flagellated protozoan Trypanosoma cruzi, the etiologic agent of Chagas disease. In this subfamily several cases of species hybridization have been reported under experimental and natural conditions. Mepraia is a genus of Triatominae endemic in Chile, responsible for transmitting T. cruzi in the sylvatic cycle. This genus includes three species, M. gajardoi, M. spinolai and M. parapatrica; however, the differentiation of M. parapatrica as a separate species remains controversial considering the possible occurrence of introgression/hybridization processes in some populations of this putative species. Mepraia species show conspicuous wing polymorphism, and it has been proposed that the genes related to wings are linked to the Y chromosome, thus wingless males could not engender winged progeny. In order to determine the degree of reproductive isolation and to assess the wing phenotype in the offspring, we performed experimental crosses between the two most divergent Mepraia species (M. gajardoi and M. spinolai) together with chromosome analyses of hybrid progenies. Although fertile F 1 hybrids were obtained in only one direction of crossing, we verified the existence of different isolation mechanisms between parental species, including hybrid breakdown. The occurrence of winged males in the offspring of wingless parental males suggests that the wing character is not linked to the Y chromosome.

Infection, Genetics and Evolution, Oct 1, 2017

Infection, Genetics and Evolution Complete mitochondrial genome of Triatoma infestans (Hemiptera,... more Infection, Genetics and Evolution Complete mitochondrial genome of Triatoma infestans (Hemiptera, Reduviidae, Triatominae), main vector of Chagas disease

Acta Tropica, Nov 1, 2015

Kissing-bugs (Triatominae) are being increasingly reported as a biting nuisance in SE Asia, with ... more Kissing-bugs (Triatominae) are being increasingly reported as a biting nuisance in SE Asia, with severe bite reactions sometimes leading to anaphylactic shock. In addition, they pose a risk for vector-borne transmission of trypanosomiasis, with potential diagnostic difficulties due to the range of trypanosome species in the region. Here, we review available information about Triatominae in Asia, and present additional comparisons using morphometry, cytogenetics, and new DNA sequence data, to clarify their relationship with each other and with the better known American species. We deduce that all Asian Triatominae have probably derived from forms originally spread during the 15-18th centuries on sailing ships, from the area that now forms the southern USA.

Memorias Do Instituto Oswaldo Cruz, 2000

A sylvatic Triatoma infestans DM (dark morph) population detected in the Bolivian Chaco was chara... more A sylvatic Triatoma infestans DM (dark morph) population detected in the Bolivian Chaco was characterized and compared with various domestic ones. The degree of differentiation of DM was clearly within the T. infestans intra-specific level. Nevertheless marked chromatic and morphometric differences as well as differences in antennal pattern, chromosome banding and randomly amplified polymorphic DNA support the hypothesis of a distinct population. Continuous exchange of insects between wild and domestic habitats seems unlikely in the Chaco.

Infection, Genetics and Evolution, May 1, 2002

Panstrongylus species are widely distributed throughout the Americas, where they act as vectors o... more Panstrongylus species are widely distributed throughout the Americas, where they act as vectors of Trypanosoma cruzi, agent of Chagas disease. Their intraspecific relationships, taxonomic position and phylogeny in relation to other Triatomini were explored using ribosomal DNA (rDNA) internal transcribed spacer 2 (ITS-2) sequence polymorphisms and maximum parsimony, distance and maximum likelihood analyses of 10 populations representing six species of the genus (P. megistus, P. geniculatus, P. rufotuberculatus, P. lignarius, P. herreri and P. chinai). At the subspecific level, P. megistus appeared more homogeneous than P. rufotuberculatus and P. geniculatus (both with broader distribution). Several dinucleotide microsatellites were detected in the sequences of given species. Many of these microsatellites (GC, TA, GT and AT) showed different number of repeats in different populations and thus, may be very useful for population differentiation and dynamics analyses in future studies. The sequences of P. lignarius (considered sylvatic) and P. herreri (a major disease vector in Peru) were identical, suggesting that these species should be synonymised. Intrageneric analysis showed a clear separation of P. rufotuberculatus, with closest relationships between P. geniculatus and P. chinai, and P. megistus occupying a separate branch. Genetic distances between Panstrongylus species (0.11585-0.22131) were higher than those between Panstrongylus and other Triatomini (16 species from central and North America and South America) (0.08617-0.11039). The distance between P. megistus and P. lignarius/herreri (0.22131) was the largest so far recorded in the tribe. The pronounced differences in length and nucleotide composition suggest a relatively old divergence of Panstrongylus species. P. rufotuberculatus was closer to Mesoamerican Triatoma, Meccus and Dipetalogaster species than to other Panstrongylus. All Panstrongylus clustered with the Mesoamerican clade; P. rufotuberculatus clustered with the phyllosoma complex and T. dimidiata, with D. maxima and T. barberi in a basal position. The rest of Panstrongylus appeared paraphyletically in the tree. This is evidence suggesting polyphyly within the genus Panstrongylus, whose species may be related to the ancestors giving rise to central and North American Triatomini.

Memorias Do Instituto Oswaldo Cruz, Sep 1, 1999

DNA sequence comparison of 412 base-pairs fragments of the mitochondrial cytochrome B gene was us... more DNA sequence comparison of 412 base-pairs fragments of the mitochondrial cytochrome B gene was used to infer the genetic structure of nine geographical Triatoma infestans populations and their phylogenetic relationship with T. melanosoma and T. brasiliensis. T. infestans and T. melanosoma were compared by morphometry, allozyme and cytogenetic analyses, as well as subjected to reciprocal crosses, in order to clarify the taxonomic status of the latter. No differences were found to distinguish the two species and the crosses between them yielded progeny. T. infestans populations presented four haplotypes that could be separated in two clusters: one formed by the samples from Bolivia (Andes and Chaco) and the other formed by samples from Argentina and Brazil. Silvatic and domestic T. infestans populations from Bolivia (Andes) were genetically identical.

Randomly amplified polymorphic DNA (RAPD) and nuclear ribosomal DNA sequence analyses were used t... more Randomly amplified polymorphic DNA (RAPD) and nuclear ribosomal DNA sequence analyses were used to assess the genetic population structure of the South American triatomine species Triatoma rubrovaria throughout its geographical distribution. To investigate the genetic variability at both intraspecific and intrapopulational levels the RAPD profiles and the nucleotide sequences of the rDNA intergenic spacers, ITS-1 and ITS-2, were analysed and compared. The phenetic analysis based on RAPD profiles show three distinct clusters diverging by similarity coefficients ranging from 0.62 to 0.96. The ITS-1 and ITS-2 sequence variability detected may be considered very high, suggesting reproductive isolation between populations. A total of seven composite haplotypes (CH) were found, among which three are specific for Brazil, other three for Uruguay, and the last one common for the three countries studied. The population studied in Argentina does not represent an independent CH. Sequence analyses proved that the five populations studied are easily differentiable and that there is heterogeneity within each one. True mutations and indels are the responsible of sequence differences between haplotypes and populations, suggesting that divergence processes may presently go on within this species. The large intraspecific variability detected may underlie the known plasticity of T. rubrovaria, making it a potential intradomiciliary invader and consequently an appropriate vector for Chagas disease transmission. Therefore, this triatomine species must be continuously monitored throughout.

Cytogenetic and Genome Research, 2010

The subfamily Triatominae (Hemiptera, Reduviidae), vectors of Chagas disease, includes over 140 s... more The subfamily Triatominae (Hemiptera, Reduviidae), vectors of Chagas disease, includes over 140 species. Karyotypic information is currently available for 80 of these species. This paper summarizes the chromosomal variability of the subfamily and how it may reveal aspects of genome evolution in this group. The Triatominae present a highly conserved chromosome number. All species, except 3, present 20 autosomes. The differences in chromosome number are mainly caused by variation in the number of sex chromosomes, due to the existence of 3 sex systems in males (XY, X1X2Y and X1X2X3Y). However, inter- and intraspecific differences in the position, quantity and meiotic behavior of constitutive heterochromatin, in the total genome size, and in the location of ribosomal 45S rRNA clusters, have revealed considerable cytogenetic variability within the subfamily. This cytogenetic diversity offers the opportunity to perform cytotaxonomic and phylogenetic studies, as well as structural, evolutionary, and functional analyses of the genome. The imminent availability of the complete genome of Rhodnius prolixus also opens new perspectives for understanding the evolution and genome expression of triatomines. The application of fluorescence in situ hybridization for the mapping of genes and sequences, as well as comparative analyses of genome homology by comparative genomic hybridization will be useful tools for understanding the genomic changes in relation to evolutionary processes such as speciation and adaptation to different environments.

American Journal of Tropical Medicine and Hygiene, Dec 1, 1997

Three species of triatomine bugs, Triatoma sordida, T. guasayana, and T. patagonica, were examine... more Three species of triatomine bugs, Triatoma sordida, T. guasayana, and T. patagonica, were examined by cytogenetic (C-banded karyotypes and male meiotic process) and isoenzymatic studies. These three species, with different importance as Chagas' disease vectors, were found to be closely related according to their known ethologic, ecologic, and morphologic traits. Although they have the same diploid chromosome number (2n = 22 constituted by 20 autosomes and an XY male/XX female sex mechanism), each species has a distinct chromosomal behavior during male meiosis and a specific amount and localization of C-heterochromatic blocks. Moreover, these chromosome characteristics allowed us to differentiate two T. sordida populations. Isoenzymatic data confirmed the taxonomic status of the three species and together with our cytogenetic results questioned the species homogeneity of T. sordida.

Medical and Veterinary Entomology

Triatoma maculata (Hemiptera, Reduviidae, Triatominae) occurs across dry‐to‐semiarid ecoregions o... more Triatoma maculata (Hemiptera, Reduviidae, Triatominae) occurs across dry‐to‐semiarid ecoregions of northern South America, where it transmits Trypanosoma cruzi, causative agent of Chagas disease. Using 207 field‐caught specimens from throughout the species' range, mitochondrial(mt) DNA sequence data, and cytogenetics, we investigated inter‐population genetic diversity and the phylogenetic affinities of T. maculata. Mitochondrial DNA sequence analyses (cytb and nd4) disclosed a monophyletic T. maculata clade encompassing three distinct geographic groups: Roraima formation (Guiana shield), Orinoco basin, and Magdalena basin (trans‐Andean). Between‐group cytb distances (11.0–12.8%) were larger than the ~7.5% expected for sister Triatoma species; the most recent common ancestor of these T. maculata groups may date back to the late Miocene. C‐heterochromatin distribution and the sex‐chromosome location of 45S ribosomal DNA clusters both distinguished Roraima bugs from Orinoco and Mag...

Emerging Infectious Diseases, Mar 1, 2004

We analyzed the main karyologic changes that have occurred during the dispersal of Triatoma infes... more We analyzed the main karyologic changes that have occurred during the dispersal of Triatoma infestans, the main vector of Chagas disease. We identified two allopatric groups, named Andean and non-Andean. The Andean specimens present C-heterochromatic blocks in most of their 22 chromosomes, whereas non-Andean specimens have only 4-7 autosomes with C-banding. These heterochromatin differences are the likely cause of a striking DNA content variation (approximately 30%) between Andean and non-Andean insects. Our study, together with previous historical and genetic data, suggests that T. infestans was originally a sylvatic species, with large quantities of DNA and heterochromatin, inhabiting the Andean region of Bolivia. However, the spread of domestic T. infestans throughout the non-Andean regions only involved insects with an important reduction of heterochromatin and DNA amounts. We propose that heterochromatin and DNA variation mainly reflected adaptive genomic changes that contribute to the ability of T. infestans to survive, reproduce, and disperse in different environments. A merican trypanosomiasis or Chagas disease is well recognized as the most serious human parasitic disease of the Americas in terms of its social and economic impact (1). This disease is caused by the flagellate protozoan Trypanosoma cruzi, and it is transmitted by bloodsucking insects of the subfamily Triatominae (Hemiptera, Reduviidae). There is no vaccine against T. cruzi; therefore, disease control relies on eliminating domestic vector populations by spraying infested houses with residual insecticides. The epidemiologic importance of Chagas disease vectors largely depends on the vectors' spreading ability and adaptation to domestic habitats. Therefore, studies on the changes that have taken place in such domestication and geographic expansion may contribute to understanding the basic process by which some species of Triatominae invade new habitats and colonize human habitations. These analyses are fundamental in the design of control campaigns because their results will help determine the most appropiate strategy for insecticide application. Knowledge of the genetic structure of insect populations (including the evaluation of gene flow between domestic and sylvatic populations), as well as their domestication and spreading capabilities, are essential tools for effective vector control (2). Triatoma infestans represents the best example of spreading and adaptation to domicilies observed in a triatomine species. This species is the main and widespread vector in South America, responsible for about half of the 12 million cases of Chagas disease reported worldwide. Although its distribution is now being substantially reduced by large-scale control interventions within the Southern Cone Initiative, launched in 1991 by six South American countries (1), its distribution in the mid-1980s was very wide, including vast regions of Argentina, Bolivia, Brazil, Chile, Paraguay, southern Peru, and Uruguay (Figure 1). T. infestans is found almost exclusively in domestic and peridomestic environments, occupying cracks and crevices in rural dwellings and domestic animal enclosures. The presence of this species in sylvatic habitats (rock piles in association with wild guinea pigs) has only been confirmed in the Andean valleys of Cochabamba and Sucre in Bolivia (3-5). This finding, together with historical reconstruction (6) and genetic analyses (7), suggests that central Bolivia may be the site of origin and dispersal of T. infestans throughout South America. One important approach used to establish genetic variation in T. infestans is cytogenetic analysis. The diploid chromosome number of T. infestans is 22, including 10 pairs of autosomes and 1 pair of sex chromosomes (XY in males, XX in females) (8). The three large autosomal pairs and the Y chromosome present C-heterochromatic blocks 438

Comparative Cytogenetics, Dec 18, 2014

Species of infraorder Cimicomorpha of Heteroptera exhibit holokinetic chromosomes with inverted m... more Species of infraorder Cimicomorpha of Heteroptera exhibit holokinetic chromosomes with inverted meiosis for sex chromosomes and high variation in chromosome number. The family Reduviidae, which belongs to this infraorder, is also recognized by high variability of heterochromatic bands and chromosome location of 18S rDNA loci. We studied here five species of Reduviidae (Harpactorinae) with predator habit, which are especially interesting because individuals are found solitary and dispersed in nature. These species showed striking variation in chromosome number (including sex chromosome systems), inter-chromosomal asymmetry, different number and chromosome location of 18S rDNA loci, dissimilar location and quantity of autosomal C-heterochromatin, and different types of repetitive DNA by fluorochrome banding, probably associated with occurrence of different chromosome rearrangements. Terminal chromosome location of C-heterochromatin seems to reinforce the model of equilocal dispersion of repetitive DNA families based in the "bouquet configuration".

Medical and Veterinary Entomology, 1998

Among collections of Triatoina spiitolai from various sites in northern Chile, adults from coasta... more Among collections of Triatoina spiitolai from various sites in northern Chile, adults from coastal populations are invariably wingless, whereas inland populations show balanced alary polymorphism between wingless females and males that are either winged or wingless. Laboratory crosses showed that male offspring from normal-winged parents were always winged (88% long-winged) and those from long-winged male parents were all long-winged. The male offspring from wingless males always included winged males: 11/33 = 33%, of which 8/11 = 73% were longwinged. An X-linked mutation is proposed to inhibit wing development. Field studies of population demography indicate that male alary polymorphism is advantageous in the desert environment of northern Chile.

Zootaxa, May 2, 2016

Triatoma bahiensis Sherlock &... more Triatoma bahiensis Sherlock & Serafim, 1967, T. lenti Sherlock & Serafim, 1967, and T. pessoai Sherlock & Serafim, 1967 were described based on material collected in the Brazilian state of Bahia. These species were later included in the T. brasiliensis complex based on their geographic distribution. Triatoma bahiensis and T. pessoai were subsequently synonymized with T. lenti. However, the phylogenetic position of T. lenti within the T. brasiliensis complex has remained doubtful. This study aims to assess the taxonomic status of T. bahiensis and to infer the phylogenetic relationships between T. lenti, T. bahiensis and the other members of the T. brasiliensis species complex. The identities of the species in concern were confirmed by comparisons with high resolution photos of the respective type materials; lectotypes are designated for T. pessoai and T. bahiensis. Morphological, morphometric, molecular, and cytogenetic approaches as well as experimental crosses were used. The low viability of experimental crosses combined with morphological and morphometric data allow the differentiation of T. bahiensis and T. lenti. Pairwise cyt b sequence divergence between T. lenti and T. bahiensis was 2.5%. Cytogenetic and molecular analyses grouped T. lenti and T. bahiensis as members of the T. brasiliensis complex. These results revalidate the specific status of T. bahiensis.

Transactions of The Royal Society of Tropical Medicine and Hygiene, Sep 1, 1991

Transactions of the Royal Society of Tropical Medicine and Hygiene, Volume 85, Issue 5, Pages 679... more Transactions of the Royal Society of Tropical Medicine and Hygiene, Volume 85, Issue 5, Pages 679-680, September 1991, Authors:JP Dujardin; MT Garcia-Zapata; J. Jurberg; P. Roelants; L. Cardozo; F. Panzera; JCP Dias; CJ Schofield.

We analyzed the main karyologic changes that have occurred during the dispersal of Triatoma infes... more We analyzed the main karyologic changes that have occurred during the dispersal of Triatoma infestans, the main vector of Chagas disease. We identified two allopatric groups, named Andean and non-Andean. The Andean specimens present C-heterochromatic blocks in most of their 22 chromosomes, whereas non-Andean specimens have only 4-7 autosomes with C-banding. These heterochromatin differences are the likely cause of a striking DNA content variation (approximately 30%) between Andean and non-Andean insects. Our study, together with previous historical and genetic data, suggests that T. infestans was originally a sylvatic species, with large quantities of DNA and heterochromatin, inhabiting the Andean region of Bolivia. However, the spread of domestic T. infestans throughout the non-Andean regions only involved insects with an important reduction of heterochromatin and DNA amounts. We propose that heterochromatin and DNA variation mainly reflected adaptive genomic changes that contribute to the ability of T. infestans to survive, reproduce, and disperse in different environments. A merican trypanosomiasis or Chagas disease is well recognized as the most serious human parasitic disease of the Americas in terms of its social and economic impact (1). This disease is caused by the flagellate protozoan Trypanosoma cruzi, and it is transmitted by bloodsucking insects of the subfamily Triatominae (Hemiptera, Reduviidae). There is no vaccine against T. cruzi; therefore, disease control relies on eliminating domestic vector populations by spraying infested houses with residual insecticides. The epidemiologic importance of Chagas disease vectors largely depends on the vectors' spreading ability and adaptation to domestic habitats. Therefore, studies on the changes that have taken place in such domestication and geographic expansion may contribute to understanding the basic process by which some species of Triatominae invade new habitats and colonize human habitations. These analyses are fundamental in the design of control campaigns because their results will help determine the most appropiate strategy for insecticide application. Knowledge of the genetic structure of insect populations (including the evaluation of gene flow between domestic and sylvatic populations), as well as their domestication and spreading capabilities, are essential tools for effective vector control (2). Triatoma infestans represents the best example of spreading and adaptation to domicilies observed in a triatomine species. This species is the main and widespread vector in South America, responsible for about half of the 12 million cases of Chagas disease reported worldwide. Although its distribution is now being substantially reduced by large-scale control interventions within the Southern Cone Initiative, launched in 1991 by six South American countries (1), its distribution in the mid-1980s was very wide, including vast regions of Argentina, Bolivia, Brazil, Chile, Paraguay, southern Peru, and Uruguay (Figure 1). T. infestans is found almost exclusively in domestic and peridomestic environments, occupying cracks and crevices in rural dwellings and domestic animal enclosures. The presence of this species in sylvatic habitats (rock piles in association with wild guinea pigs) has only been confirmed in the Andean valleys of Cochabamba and Sucre in Bolivia (3-5). This finding, together with historical reconstruction (6) and genetic analyses (7), suggests that central Bolivia may be the site of origin and dispersal of T. infestans throughout South America. One important approach used to establish genetic variation in T. infestans is cytogenetic analysis. The diploid chromosome number of T. infestans is 22, including 10 pairs of autosomes and 1 pair of sex chromosomes (XY in males, XX in females) (8). The three large autosomal pairs and the Y chromosome present C-heterochromatic blocks 438

... Document details. Title Sex chromosomes of Neotropical Coleoptera from Uruguay. Authors Posti... more ... Document details. Title Sex chromosomes of Neotropical Coleoptera from Uruguay. Authors Postiglioni, A.; Mazzella, MC; Panzera, F.; Silva, A. da; Ponce de León, RP; Kvasina, L.; Scvortzoff, E. Conference paper; Journal article Nucleus (Calcutta) 1990 Vol. 33 No. 1-2 pp. ...

Infection, Genetics and Evolution, Nov 1, 2016

Hematophagous insects of the subfamily Triatominae include several species with a large variety o... more Hematophagous insects of the subfamily Triatominae include several species with a large variety of shapes, behavior and distribution. They have great epidemiological importance since most of them transmit the flagellated protozoan Trypanosoma cruzi, the etiologic agent of Chagas disease. In this subfamily several cases of species hybridization have been reported under experimental and natural conditions. Mepraia is a genus of Triatominae endemic in Chile, responsible for transmitting T. cruzi in the sylvatic cycle. This genus includes three species, M. gajardoi, M. spinolai and M. parapatrica; however, the differentiation of M. parapatrica as a separate species remains controversial considering the possible occurrence of introgression/hybridization processes in some populations of this putative species. Mepraia species show conspicuous wing polymorphism, and it has been proposed that the genes related to wings are linked to the Y chromosome, thus wingless males could not engender winged progeny. In order to determine the degree of reproductive isolation and to assess the wing phenotype in the offspring, we performed experimental crosses between the two most divergent Mepraia species (M. gajardoi and M. spinolai) together with chromosome analyses of hybrid progenies. Although fertile F 1 hybrids were obtained in only one direction of crossing, we verified the existence of different isolation mechanisms between parental species, including hybrid breakdown. The occurrence of winged males in the offspring of wingless parental males suggests that the wing character is not linked to the Y chromosome.

Infection, Genetics and Evolution, Oct 1, 2017

Infection, Genetics and Evolution Complete mitochondrial genome of Triatoma infestans (Hemiptera,... more Infection, Genetics and Evolution Complete mitochondrial genome of Triatoma infestans (Hemiptera, Reduviidae, Triatominae), main vector of Chagas disease

Acta Tropica, Nov 1, 2015

Kissing-bugs (Triatominae) are being increasingly reported as a biting nuisance in SE Asia, with ... more Kissing-bugs (Triatominae) are being increasingly reported as a biting nuisance in SE Asia, with severe bite reactions sometimes leading to anaphylactic shock. In addition, they pose a risk for vector-borne transmission of trypanosomiasis, with potential diagnostic difficulties due to the range of trypanosome species in the region. Here, we review available information about Triatominae in Asia, and present additional comparisons using morphometry, cytogenetics, and new DNA sequence data, to clarify their relationship with each other and with the better known American species. We deduce that all Asian Triatominae have probably derived from forms originally spread during the 15-18th centuries on sailing ships, from the area that now forms the southern USA.

Memorias Do Instituto Oswaldo Cruz, 2000

A sylvatic Triatoma infestans DM (dark morph) population detected in the Bolivian Chaco was chara... more A sylvatic Triatoma infestans DM (dark morph) population detected in the Bolivian Chaco was characterized and compared with various domestic ones. The degree of differentiation of DM was clearly within the T. infestans intra-specific level. Nevertheless marked chromatic and morphometric differences as well as differences in antennal pattern, chromosome banding and randomly amplified polymorphic DNA support the hypothesis of a distinct population. Continuous exchange of insects between wild and domestic habitats seems unlikely in the Chaco.

Infection, Genetics and Evolution, May 1, 2002

Panstrongylus species are widely distributed throughout the Americas, where they act as vectors o... more Panstrongylus species are widely distributed throughout the Americas, where they act as vectors of Trypanosoma cruzi, agent of Chagas disease. Their intraspecific relationships, taxonomic position and phylogeny in relation to other Triatomini were explored using ribosomal DNA (rDNA) internal transcribed spacer 2 (ITS-2) sequence polymorphisms and maximum parsimony, distance and maximum likelihood analyses of 10 populations representing six species of the genus (P. megistus, P. geniculatus, P. rufotuberculatus, P. lignarius, P. herreri and P. chinai). At the subspecific level, P. megistus appeared more homogeneous than P. rufotuberculatus and P. geniculatus (both with broader distribution). Several dinucleotide microsatellites were detected in the sequences of given species. Many of these microsatellites (GC, TA, GT and AT) showed different number of repeats in different populations and thus, may be very useful for population differentiation and dynamics analyses in future studies. The sequences of P. lignarius (considered sylvatic) and P. herreri (a major disease vector in Peru) were identical, suggesting that these species should be synonymised. Intrageneric analysis showed a clear separation of P. rufotuberculatus, with closest relationships between P. geniculatus and P. chinai, and P. megistus occupying a separate branch. Genetic distances between Panstrongylus species (0.11585-0.22131) were higher than those between Panstrongylus and other Triatomini (16 species from central and North America and South America) (0.08617-0.11039). The distance between P. megistus and P. lignarius/herreri (0.22131) was the largest so far recorded in the tribe. The pronounced differences in length and nucleotide composition suggest a relatively old divergence of Panstrongylus species. P. rufotuberculatus was closer to Mesoamerican Triatoma, Meccus and Dipetalogaster species than to other Panstrongylus. All Panstrongylus clustered with the Mesoamerican clade; P. rufotuberculatus clustered with the phyllosoma complex and T. dimidiata, with D. maxima and T. barberi in a basal position. The rest of Panstrongylus appeared paraphyletically in the tree. This is evidence suggesting polyphyly within the genus Panstrongylus, whose species may be related to the ancestors giving rise to central and North American Triatomini.

Memorias Do Instituto Oswaldo Cruz, Sep 1, 1999

DNA sequence comparison of 412 base-pairs fragments of the mitochondrial cytochrome B gene was us... more DNA sequence comparison of 412 base-pairs fragments of the mitochondrial cytochrome B gene was used to infer the genetic structure of nine geographical Triatoma infestans populations and their phylogenetic relationship with T. melanosoma and T. brasiliensis. T. infestans and T. melanosoma were compared by morphometry, allozyme and cytogenetic analyses, as well as subjected to reciprocal crosses, in order to clarify the taxonomic status of the latter. No differences were found to distinguish the two species and the crosses between them yielded progeny. T. infestans populations presented four haplotypes that could be separated in two clusters: one formed by the samples from Bolivia (Andes and Chaco) and the other formed by samples from Argentina and Brazil. Silvatic and domestic T. infestans populations from Bolivia (Andes) were genetically identical.

Randomly amplified polymorphic DNA (RAPD) and nuclear ribosomal DNA sequence analyses were used t... more Randomly amplified polymorphic DNA (RAPD) and nuclear ribosomal DNA sequence analyses were used to assess the genetic population structure of the South American triatomine species Triatoma rubrovaria throughout its geographical distribution. To investigate the genetic variability at both intraspecific and intrapopulational levels the RAPD profiles and the nucleotide sequences of the rDNA intergenic spacers, ITS-1 and ITS-2, were analysed and compared. The phenetic analysis based on RAPD profiles show three distinct clusters diverging by similarity coefficients ranging from 0.62 to 0.96. The ITS-1 and ITS-2 sequence variability detected may be considered very high, suggesting reproductive isolation between populations. A total of seven composite haplotypes (CH) were found, among which three are specific for Brazil, other three for Uruguay, and the last one common for the three countries studied. The population studied in Argentina does not represent an independent CH. Sequence analyses proved that the five populations studied are easily differentiable and that there is heterogeneity within each one. True mutations and indels are the responsible of sequence differences between haplotypes and populations, suggesting that divergence processes may presently go on within this species. The large intraspecific variability detected may underlie the known plasticity of T. rubrovaria, making it a potential intradomiciliary invader and consequently an appropriate vector for Chagas disease transmission. Therefore, this triatomine species must be continuously monitored throughout.

Cytogenetic and Genome Research, 2010

The subfamily Triatominae (Hemiptera, Reduviidae), vectors of Chagas disease, includes over 140 s... more The subfamily Triatominae (Hemiptera, Reduviidae), vectors of Chagas disease, includes over 140 species. Karyotypic information is currently available for 80 of these species. This paper summarizes the chromosomal variability of the subfamily and how it may reveal aspects of genome evolution in this group. The Triatominae present a highly conserved chromosome number. All species, except 3, present 20 autosomes. The differences in chromosome number are mainly caused by variation in the number of sex chromosomes, due to the existence of 3 sex systems in males (XY, X1X2Y and X1X2X3Y). However, inter- and intraspecific differences in the position, quantity and meiotic behavior of constitutive heterochromatin, in the total genome size, and in the location of ribosomal 45S rRNA clusters, have revealed considerable cytogenetic variability within the subfamily. This cytogenetic diversity offers the opportunity to perform cytotaxonomic and phylogenetic studies, as well as structural, evolutionary, and functional analyses of the genome. The imminent availability of the complete genome of Rhodnius prolixus also opens new perspectives for understanding the evolution and genome expression of triatomines. The application of fluorescence in situ hybridization for the mapping of genes and sequences, as well as comparative analyses of genome homology by comparative genomic hybridization will be useful tools for understanding the genomic changes in relation to evolutionary processes such as speciation and adaptation to different environments.

American Journal of Tropical Medicine and Hygiene, Dec 1, 1997

Three species of triatomine bugs, Triatoma sordida, T. guasayana, and T. patagonica, were examine... more Three species of triatomine bugs, Triatoma sordida, T. guasayana, and T. patagonica, were examined by cytogenetic (C-banded karyotypes and male meiotic process) and isoenzymatic studies. These three species, with different importance as Chagas' disease vectors, were found to be closely related according to their known ethologic, ecologic, and morphologic traits. Although they have the same diploid chromosome number (2n = 22 constituted by 20 autosomes and an XY male/XX female sex mechanism), each species has a distinct chromosomal behavior during male meiosis and a specific amount and localization of C-heterochromatic blocks. Moreover, these chromosome characteristics allowed us to differentiate two T. sordida populations. Isoenzymatic data confirmed the taxonomic status of the three species and together with our cytogenetic results questioned the species homogeneity of T. sordida.

Medical and Veterinary Entomology

Triatoma maculata (Hemiptera, Reduviidae, Triatominae) occurs across dry‐to‐semiarid ecoregions o... more Triatoma maculata (Hemiptera, Reduviidae, Triatominae) occurs across dry‐to‐semiarid ecoregions of northern South America, where it transmits Trypanosoma cruzi, causative agent of Chagas disease. Using 207 field‐caught specimens from throughout the species' range, mitochondrial(mt) DNA sequence data, and cytogenetics, we investigated inter‐population genetic diversity and the phylogenetic affinities of T. maculata. Mitochondrial DNA sequence analyses (cytb and nd4) disclosed a monophyletic T. maculata clade encompassing three distinct geographic groups: Roraima formation (Guiana shield), Orinoco basin, and Magdalena basin (trans‐Andean). Between‐group cytb distances (11.0–12.8%) were larger than the ~7.5% expected for sister Triatoma species; the most recent common ancestor of these T. maculata groups may date back to the late Miocene. C‐heterochromatin distribution and the sex‐chromosome location of 45S ribosomal DNA clusters both distinguished Roraima bugs from Orinoco and Mag...

Emerging Infectious Diseases, Mar 1, 2004

We analyzed the main karyologic changes that have occurred during the dispersal of Triatoma infes... more We analyzed the main karyologic changes that have occurred during the dispersal of Triatoma infestans, the main vector of Chagas disease. We identified two allopatric groups, named Andean and non-Andean. The Andean specimens present C-heterochromatic blocks in most of their 22 chromosomes, whereas non-Andean specimens have only 4-7 autosomes with C-banding. These heterochromatin differences are the likely cause of a striking DNA content variation (approximately 30%) between Andean and non-Andean insects. Our study, together with previous historical and genetic data, suggests that T. infestans was originally a sylvatic species, with large quantities of DNA and heterochromatin, inhabiting the Andean region of Bolivia. However, the spread of domestic T. infestans throughout the non-Andean regions only involved insects with an important reduction of heterochromatin and DNA amounts. We propose that heterochromatin and DNA variation mainly reflected adaptive genomic changes that contribute to the ability of T. infestans to survive, reproduce, and disperse in different environments. A merican trypanosomiasis or Chagas disease is well recognized as the most serious human parasitic disease of the Americas in terms of its social and economic impact (1). This disease is caused by the flagellate protozoan Trypanosoma cruzi, and it is transmitted by bloodsucking insects of the subfamily Triatominae (Hemiptera, Reduviidae). There is no vaccine against T. cruzi; therefore, disease control relies on eliminating domestic vector populations by spraying infested houses with residual insecticides. The epidemiologic importance of Chagas disease vectors largely depends on the vectors' spreading ability and adaptation to domestic habitats. Therefore, studies on the changes that have taken place in such domestication and geographic expansion may contribute to understanding the basic process by which some species of Triatominae invade new habitats and colonize human habitations. These analyses are fundamental in the design of control campaigns because their results will help determine the most appropiate strategy for insecticide application. Knowledge of the genetic structure of insect populations (including the evaluation of gene flow between domestic and sylvatic populations), as well as their domestication and spreading capabilities, are essential tools for effective vector control (2). Triatoma infestans represents the best example of spreading and adaptation to domicilies observed in a triatomine species. This species is the main and widespread vector in South America, responsible for about half of the 12 million cases of Chagas disease reported worldwide. Although its distribution is now being substantially reduced by large-scale control interventions within the Southern Cone Initiative, launched in 1991 by six South American countries (1), its distribution in the mid-1980s was very wide, including vast regions of Argentina, Bolivia, Brazil, Chile, Paraguay, southern Peru, and Uruguay (Figure 1). T. infestans is found almost exclusively in domestic and peridomestic environments, occupying cracks and crevices in rural dwellings and domestic animal enclosures. The presence of this species in sylvatic habitats (rock piles in association with wild guinea pigs) has only been confirmed in the Andean valleys of Cochabamba and Sucre in Bolivia (3-5). This finding, together with historical reconstruction (6) and genetic analyses (7), suggests that central Bolivia may be the site of origin and dispersal of T. infestans throughout South America. One important approach used to establish genetic variation in T. infestans is cytogenetic analysis. The diploid chromosome number of T. infestans is 22, including 10 pairs of autosomes and 1 pair of sex chromosomes (XY in males, XX in females) (8). The three large autosomal pairs and the Y chromosome present C-heterochromatic blocks 438