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Made available in DSpace on 2022-04-29T08:35:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Background: Triatoma sordida is one of the main Chagas disease vectors in Brazil. In addition to Brazil, this species has already been reported in Bolivia, Argentina, Paraguay, and Uruguay. It is hypothesized that the insects currently identified as T. sordida are a species subcomplex formed by three cytotypes (T. sordida sensu stricto [s.s.], T. sordida La Paz, and T. sordida Argentina). With the recent description of T. rosai from the Argentinean specimens, it became necessary to assess the taxonomic status of T. sordida from La Paz, Bolivia, since it was suggested that it may represent a new species, which has taxonomic, evolutionary, and epidemiological implications. Based on the above, we carried out molecular and experimental crossover studies to assess the specific status of T. sordida La Paz. Methods: To evaluate the pre- and postzygotic barriers between T. sordida La Paz and T. sordida s.s., experimental crosses and intercrosses between F1 hybrids and between F2 hybrids were conducted. In addition, cytogenetic analyses of the F1 and F2 hybrids were applied with an emphasis on the degree of pairing between the homeologous chromosomes, and morphological analyses of the male gonads were performed to evaluate the presence of gonadal dysgenesis. Lastly, the genetic distance between T. sordida La Paz and T. sordida s.s. was calculated for the CYTB, ND1, and ITS1 genes. Results: Regardless of the gene used, T. sordida La Paz showed low genetic distance compared to T. sordida s.s. (below 2%). Experimental crosses resulted in offspring for both directions, demonstrating that there are no prezygotic barriers installed between these allopatric populations. Furthermore, postzygotic barriers were not observed either (since the F1 × F1 and F2 × F2 intercrosses resulted in viable offspring). Morphological and cytogenetic analyses of the male gonads of the F1 and F2 offspring demonstrated that the testes were not atrophied and did not show chromosome pairing errors. Conclusion: Based on the low genetic distance (which configures intraspecific variation), associated with the absence of prezygotic and postzygotic reproductive barriers, we confirm that T. sordida La Paz represents only a chromosomal polymorphism of T. sordida s.s. Graphical abstract: [Figure not available: see fulltext.] Laboratório de Biologia Celular Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP) Instituto de Biociências Letras e Ciências Exatas, Rua Cristóvão Colombo, 2265 Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP) Instituto de Biociências Rua Dr. Antônio Celso Wagner Zanin, 250, Distrito de Rubião Júnior Laboratório de Parasitologia Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP) Faculdade de Ciências Farmacêuticas, Rodovia Araraquara-Jaú km 1 Laboratório de Entomologia em Saúde Pública Departamento de Epidemiologia Faculdade de Saúde Pública Universidade de São Paulo, Av. Dr. Arnaldo 715 Laboratório Nacional e Internacional de Referência em Taxonomia de Triatomíneos Instituto Oswaldo Cruz (FIOCRUZ), Av. Brasil 4365, Pavilhão Rocha Lima, sala 505 Laboratório de Biologia Celular Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP) Instituto de Biociências Letras e Ciências Exatas, Rua Cristóvão Colombo, 2265 Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP) Instituto de Biociências Rua Dr. Antônio Celso Wagner Zanin, 250, Distrito de Rubião Júnior Laboratório de Parasitologia Universidade Estadual Paulista “Júlio de Mesquita Filho” (UNESP) Faculdade de Ciências Farmacêuticas, Rodovia Araraquara-Jaú km 1

Triatoma sordida is among the main Brazilian species considered as Chagas disease vectors. The genetic studies are directed mainly to phylogenetic questions because this species possibly have suffered cryptic speciation. Furthermore, there are few studies that analyzed the structure and genetic variability of specimens from Brazil and that showed low genetic diversity and strong genetic structuring of the population samples. Therefore, because of great epidemiological importance of T. sordida and mainly the restriction of genetic characterization of this vector only for populations of Minas Gerais state, this article performs a genetic analysis of the T. sordida from seven different Brazilian states (representing different biomes), by means of cytogenetic markers. All analyzed specimens presents the same cytogenetic characteristics: early meiotic prophase with several heterochromatic bodies dispersed in the nucleus (CG-rich), being one of them formed by the associated sex chromosomes surrounded by some autosomal heterochromatic regions, meiotic metaphase with most autosomal pairs exhibiting a C-heterochromatic block in one chromosomal end (CG-rich), Y sex chromosome fully heterochromatin (AT-rich), and X chromosome may present a small C-block (CG-rich). These results are important because the chromosomal markers enable to confirm and expand the low genetic diversity for all Brazilian states occupied by T. sordida, suggesting that all Brazilian populations were originated from a small ancestral population and possibly dispersed to other biomes by founder effect. In addition, we suggest that T. sordida from Brazil are not suffering cryptic speciation and we confirm the classification of all Brazilian examples as T. sordida sensu stricto.

Made available in DSpace on 2022-04-28T19:46:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-09-07 Triatoma sordida is an endemic Chagas disease vector in South America, distributed in Brazil, Bolivia, Paraguay, and Uruguay. Chromosomal, molecular, isoenzymatic, and cuticular hydrocarbon pattern studies indicate cryptic speciation in T. sordida. Recently, T. rosai was described from specimens from Argentina initially characterized as T. sordida. Although several authors assume that the speciation process that supports this differentiation in T. sordida is the result of cryptic speciation, further morphological and/or morphometric studies are necessary to prove the application of this evolutionary event, because the only morphological intraspecific comparison performed in T. sordida is based on geometric morphometry and the only interspecific comparison made is between T. rosai and T. sordida from Brazil that evaluated morphological and morphometric differences. Based on this, morphological analyses of thorax and abdomen using Scanning Electron Microscopy and morphometric analyses of the head, thorax, and abdomen among T. sordida from Brazil, Bolivia, and Paraguay, as well as T. rosai, were performed to assess whether the evolutionary process responsible for variations is the cryptic speciation phenomenon. Morphological differences in the thorax and female external genitalia, as well as morphometric differences in the head, thorax, abdomen, pronotum, and scutellum structures, were observed. Based on this, the evolutionary process that supports, so far, these divergences observed for T. sordida populations/T. sordida subcomplex is not cryptic speciation. Moreover, we draw attention to the necessity for morphological/morphometric studies to correctly apply the cryptic species/speciation terms in triatomines. Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) Instituto de Biociências de Botucatu, Distrito de Rubião Junior Laboratório de Entomologia em Saúde Pública Departamento de Epidemiologia Faculdade de Saúde Pública Universidade de São Paulo (USP) Laboratório de Parasitologia Faculdade de Ciências Farmacêuticas Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) Laboratório Nacional e Internacional de Referência em Taxonomia de Triatomíneos Instituto Oswaldo Cruz (FIOCRUZ) Pavilhão Rocha Lima Departamento de Medicina Tropical Instituto de Investigaciones en Ciencias de la Salud (IICS) Universidad Nacional de Asunción, Campus Universitario Laboratorio de Biología Molecular de Protozoarios Facultad de Medicina Instituto de Medicina Tropical Universidad Central de Venezuela Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) Instituto de Biociências de Botucatu, Distrito de Rubião Junior Laboratório de Parasitologia Faculdade de Ciências Farmacêuticas Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP)

Made available in DSpace on 2020-12-12T01:43:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The Triatoma genus is paraphyletic, and its species are grouped into complexes and subcomplexes. Given the fact that species that make up a given subcomplex generally share chromosomal traits, we analyzed the distribution of AT- and CG-rich DNA of the T. brasiliensis species subcomplex, in order to establish affinities among members of the T. brasiliensis subcomplex based on chromatin and chromosome traits and develop an identification key for the four monophyletic Triatoma subcomplexes from South America. All species exhibited a CG-rich X sex chromosome and autosomes, as well as an AT-rich Y sex chromosome. This feature can be used as a diagnostic characteristic to determine whether a given species is a member of the T. brasiliensis subcomplex, because it enables the differentiation of these species from all Triatoma of South America. Thus, we confirmed the chromosomal relationship of the T. brasiliensis species subcomplex and developed a dichotomous key based on the chromocenter to differentiate the species from this subcomplex from the other monophyletic Triatoma subcomplexes from South America. Laboratório de Parasitologia Departamento de Ciências Biológicas Faculdade de Ciências Farmacêuticas Universidade Estadual Paulista “Júlio de Mesquita Filho” FCFAR/UNESP, Rodovia Araraquara-Jaú km 1 Laboratório de Biologia Celular Departamento de Biologia Instituto de Biociências Letras e Ciências Exatas Universidade Estadual Paulista “Júlio de Mesquita Filho” IBILCE/UNESP, Rua Cristóvão Colombo 2265 Instituto de Biologia Universidade Estadual de Campinas IB/UNICAMP, Rua Monteiro Lobato, 255 Laboratório de Ecologia Animal Departamento de Engenharia e Meio Ambiente Centro de Ciências Aplicadas e Educação Universidade Federal de Paraíba CCAE/UFPB, Av. Santa Elizabete, 160 Laboratório de Parasitologia Departamento de Ciências Biológicas Faculdade de Ciências Farmacêuticas Universidade Estadual Paulista “Júlio de Mesquita Filho” FCFAR/UNESP, Rodovia Araraquara-Jaú km 1 Laboratório de Biologia Celular Departamento de Biologia Instituto de Biociências Letras e Ciências Exatas Universidade Estadual Paulista “Júlio de Mesquita Filho” IBILCE/UNESP, Rua Cristóvão Colombo 2265 FAPESP: 2013/19764-0 FAPESP: 2017/21359-8

Triatoma sordida is among the main Brazilian species considered as Chagas disease vectors. The genetic studies are directed mainly to phylogenetic questions because this species possibly have suffered cryptic speciation. Furthermore, there are few studies that analyzed the structure and genetic variability of specimens from Brazil and that showed low genetic diversity and strong genetic structuring of the population samples. Therefore, because of great epidemiological importance of T. sordida and mainly the restriction of genetic characterization of this vector only for populations of Minas Gerais state, this article performs a genetic analysis of the T. sordida from seven different Brazilian states (representing different biomes), by means of cytogenetic markers. All analyzed specimens presents the same cytogenetic characteristics: early meiotic prophase with several heterochromatic bodies dispersed in the nucleus (CG-rich), being one of them formed by the associated sex chromosomes surrounded by some autosomal heterochromatic regions, meiotic metaphase with most autosomal pairs exhibiting a C-heterochromatic block in one chromosomal end (CG-rich), Y sex chromosome fully heterochromatin (AT-rich), and X chromosome may present a small C-block (CG-rich). These results are important because the chromosomal markers enable to confirm and expand the low genetic diversity for all Brazilian states occupied by T. sordida, suggesting that all Brazilian populations were originated from a small ancestral population and possibly dispersed to other biomes by founder effect. In addition, we suggest that T. sordida from Brazil are not suffering cryptic speciation and we confirm the classification of all Brazilian examples as T. sordida sensu stricto.