Does the Polymorphism in the Length of the Polyalanine Tract of FOXE1

Background. Recent data have suggested that polymorphisms in the length of the polyalanine tract (polyA) of FOXE1 gene may act as a susceptibility factor for thyroid dysgenesis. The main purpose of this study was to investigate the influence of polyA of FOXE1 gene on the risk of thyroid dysgenesis. Method. A case-control study was conducted in a sample of 90 Brazilian patients with thyroid dysgenesis and 131 controls without family history of thyroid disease. Genomic DNA was isolated from peripheral blood samples and the genotype of each individual was determined by automated sequencing. Results. More than 90% of genotypes found in the group of patients with thyroid dysgenesis and in controls subjects were represented by sizes 14 and 16 polymorphisms in the following combinations: 14/14, 14/16, and 16/16. Genotypes 14/16 and 16/16 were more frequent in the control group, while genotype 14/14 was more frequent in the group of patients with thyroid dysgenesis. There was no difference between agenesis group and control group. Genotype 14/14 when compared to genotypes 14/16 and 16/16A showed an association with thyroid dysgenesis. Conclusion. PolyA of FOXE1 gene alters the risk of thyroid dysgenesis, which may explain in part the etiology of this disease

The molecular cytogenetic characterization of Conopophaga lineata indicates a common chromosome rearrangement in the Parvorder Furnariida (Aves, Passeriformes).

Cytogenetic analyses of the Suboscines species are still scarce, and so far, there is no karyotype description of any species belonging to the family Conopophagidae. Thus, the aim of this study is to describe and analyze the karyotype of Conopophaga lineata by chromosome painting using Gallus gallus (GGA) probes and to identify the location of the 18/28S rDNA cluster. Metaphases were obtained from fibroblast culture from two individuals of C. lineata. We observed a diploid number of 2n=78. GGA probes showed that most ancestral syntenies are conserved, except for the fission of GGA1 and GGA2, into two distinct pairs each. We identified the location of 18S rDNA genes in a pair of microchromosomes. The fission of the syntenic group corresponding to GGA2 was observed in other Furnariida, and hence may correspond to a chromosomal synapomorphy for the species of Parvorder Furnariida

Chromosomal Evolution in the Phylogenetic Context: A Remarkable Karyotype Reorganization in Neotropical Parrot Myiopsitta monachus (Psittacidae).

Myiopsitta monachus is a small Neotropical parrot (Psittaciformes: Arini Tribe) from subtropical and temperate regions of South America. It has a diploid chromosome number 2n = 48, different from other members of the Arini Tribe that have usually 70 chromosomes. The species has the lowest 2n within the Arini Tribe. In this study, we combined comparative chromosome painting with probes generated from chromosomes of Gallus gallus and Leucopternis albicollis, and FISH with bacterial artificial chromosomes (BACs) selected from the genome library of G. gallus with the aim to shed light on the dynamics of genome reorganization in M. monachus in the phylogenetic context. The homology maps showed a great number of fissions in macrochromosomes, and many fusions between microchromosomes and fragments of macrochromosomes. Our phylogenetic analysis by Maximum Parsimony agree with molecular data, placing M. monachus in a basal position within the Arini Tribe, together with Amazona aestiva (short tailed species). In M. monachus many chromosome rearrangements were found to represent autopomorphic characters, indicating that after this species split as an independent branch, an intensive karyotype reorganization took place. In addition, our results show that M. monachus probes generated by flow cytometry provide novel cytogenetic tools for the detection of avian chromosome rearrangements, since this species presents breakpoints that have not been described in other species

Karyotype Evolution in Birds: From Conventional Staining to Chromosome Painting.

In the last few decades, there have been great efforts to reconstruct the phylogeny of Neoaves based mainly on DNA sequencing. Despite the importance of karyotype data in phylogenetic studies, especially with the advent of fluorescence in situ hybridization (FISH) techniques using different types of probes, the use of chromosomal data to clarify phylogenetic proposals is still minimal. Additionally, comparative chromosome painting in birds is restricted to a few orders, while in mammals, for example, virtually all orders have already been analyzed using this method. Most reports are based on comparisons using Gallus gallus probes, and only a small number of species have been analyzed with more informative sets of probes, such as those from Leucopternis albicollis and Gyps fulvus, which show ancestral macrochromosomes rearranged in alternative patterns. Despite this, it is appropriate to review the available cytogenetic information and possible phylogenetic conclusions. In this report, the authors gather both classical and molecular cytogenetic data and describe some interesting and unique characteristics of karyotype evolution in birds

Dispersión geográfica de la familia Phyllostomidae (Chiroptera) basada en las secuencias del citocromo b

Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil / Universidade Federal do Pará. Belém, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Centro de Inovações Tecnológicas. Ananindeua, PA, Brasil / Universidade Estadual do Pará. Centro de Ciências Biológicas e da Saúde. Laboratório de Biologia Molecular. Belém, PA, Brasil.The Chiroptera order is one of the most successful species of mammals with a wide geographical distribution. This order has been traditionally divided into two suborders, Microchiroptera and Megachiroptera, and the family Phyllostomidae is included in the suborder Microchiroptera. However, studies with molecular analysis show a different classification in two different suborders: Yangochiroptera and Yinpterochiroptera. Studies with various species describe a wide dispersal of these animals from Central America to South America and specimens of different places, creating new karyotypes and different nucleotide sequences, especially in the widely known Cytochrome b gene. In this study, we analyzed a phylogeographic dispersion of the Pyllostomidae family using the mitochondrial Cytochrome b gene, a possible dispersion pattern for family and new evolutionary proposals. All the sequences were obtained from the online database (GenBank) and the analysis and formation of phylogenetic trees were performed by maximum parsimony and maximum likelihood methods. Some dispersion patterns were observed for species of genus Carollia and Glossophaga in individual analysis and other species pattern of dispersion from South to West. But in general analysis, a pattern of dispersal to the North of the American Continent was evidenced for the family, following South America to Central America, despite many landforms that could cause speciation of some genera such as isolation by the Andes mountains. Further analysis, with a greater number of specimens from different locations, must be done to confirm this theoryA ordem Chiroptera é uma das espécies de mamíferos mais bem sucedidas com uma grande distribuição geográfica. Essa ordem foi tradicionalmente dividida em duas subordens, Microchiroptera e Megachiroptera, e a família Phyllostomidae está incluída na primeira. No entanto, estudos com análise molecular mostram uma classificação diferente em duas subordens distintas: Yangochiroptera e Yinpterochiroptera. Os estudos com várias espécies descrevem uma grande dispersão desses animais da América Central para a América do Sul e espécimes de vários lugares, a criação de novos cariótipos e sequências de nucleotídeos diferentes, especialmente no gene citocromo b amplamente conhecido. Neste estudo, analisou-se uma dispersão filogeográfica da família Pyllostomidae usando o gene mitocondrial citocromo b, um possível padrão de dispersão para essa família e novas propostas evolutivas. Todas as sequências foram obtidas a partir da base de dados on-line (GenBank), a análise e a formação de árvores filogenéticas foram realizadas pelos métodos de máxima parcimônia e de máxima verossimilhança. Foram observados alguns padrões de dispersão de espécies do gênero Carollia e Glossophaga na análise individual e outro padrão de dispersão de espécies do sul ao oeste. Porém, na análise geral, um padrão de dispersão para o norte do Continente Americano foi evidenciado para a família, depois da América do Sul à América Central, apesar de muitos acidentes geográficos causarem especiação de alguns gêneros, tais como o isolamento das montanhas dos Andes. Uma análise mais aprofundada, com um maior número de amostras de diferentes locais, deve ser feita para confirmar esta teoria

The karyotype of Alouatta fusca clamitans from Rio de Janeiro, Brazil: Evidence for a y-autosome translocation

The chromosome complements of four males of Alouatta fusca clamitans, caught in Rio de Janeiro State, Brazil, were analyzed by G-, C-, and NOR-banding techniques. The diploid number found was 49 in all the specimens. The presence of a heteromorphic pair of submetacentric chromosomes in the analyzed specimens, not present in males and females with 2n = 50 previously reported, and its G-banding pattern, led us to assume that this pair is involved in a Y-autosome translocation. Thus, the sex determination system appears modified to X1X1X2X2 /X1X2Y. Heterochromatic segments were found in the pericentromeric region of all the chromosomes, in the telomeric region of the short arm in pair 2, in the complete length of the short arm of pairs 5 and 6 and in the intercalary region of the long arm in pair 17. The nucleolar organizer regions were situated in the intercalary region of the long arm in two small acrocentric pairs.Os cariótipos referentes a quatro machos de Alouatta fusca clamitans oriundos do Rio de Janeiro foram analisados através de técnicas de bandamento G, C e NOR. O número diplóide em todos os espécimes foi igual a 49, com a presença de três cromossomos não pareados. A comparação dos padrões de bandamento G com espécimes previamente descritos com 2n = 50 revelou a ocorrência de uma translocação do tipo Y-autossomo, modificando o sistema cromossômico de determinação sexual para o tipo múltiplo, X1X2Y/X1X1 X2X2. Os blocos de heterocromatina constitutiva se distribuíram na região pericentromérica de todos os cromossomos; segmentos intercalares e teloméricos foram visualizados em um par acrocêntrico e em outro submetacêntrico, respectivamente. As regiões organizadoras de nucléolo se localizaram no braço longo de dois pares de pequenos acrocêntricos

Does the Polymorphism in the Length of the Polyalanine Tract of FOXE1 Gene Influence the Risk of Thyroid Dysgenesis Occurrence?

Background. Recent data have suggested that polymorphisms in the length of the polyalanine tract (polyA) of FOXE1 gene may act as a susceptibility factor for thyroid dysgenesis. The main purpose of this study was to investigate the influence of polyA of FOXE1 gene on the risk of thyroid dysgenesis. Method. A case-control study was conducted in a sample of 90 Brazilian patients with thyroid dysgenesis and 131 controls without family history of thyroid disease. Genomic DNA was isolated from peripheral blood samples and the genotype of each individual was determined by automated sequencing. Results. More than 90% of genotypes found in the group of patients with thyroid dysgenesis and in controls subjects were represented by sizes 14 and 16 polymorphisms in the following combinations: 14/14, 14/16, and 16/16. Genotypes 14/16 and 16/16 were more frequent in the control group, while genotype 14/14 was more frequent in the group of patients with thyroid dysgenesis. There was no difference between agenesis group and control group. Genotype 14/14 when compared to genotypes 14/16 and 16/16A showed an association with thyroid dysgenesis. Conclusion. PolyA of FOXE1 gene alters the risk of thyroid dysgenesis, which may explain in part the etiology of this disease

Cytogenetics description in Batrachoides surinamensis, (Batrachoididae: Batrachoidiformes): what does the estuary have to say?

Universidade Federal do Pará. Campus Universitário de Bragança. Instituto de Estudos Costeiros. Bragança, PA, Brazil.Universidade Federal do Pará. Campus Universitário de Bragança. Instituto de Estudos Costeiros. Bragança, PA, Brazil.Universidade Federal do Pará. Campus Universitário de Bragança. Instituto de Estudos Costeiros. Bragança, PA, Brazil / Universidade do Porto. Campus agrário de Vairão. Laboratório Associado. Centro de Investigação em Biodiversidade e Recursos Genéticos. Vairão, PT, Portugal.Universidade Federal de São Carlos. Laboratório de Citogenética de Peixes. Departamento de Genética e Evolução. São Carlos, SP, Brazil.Universidade Federal do Rio Grande do Norte - Campus Universitário. Centro de Biociências. Departamento de Biologia Celular e Genética. Natal, RN, Brazil.Universidade Federal do Pará - Campus Universitário de Belém.Instituto de Ciências Exatas e Naturais. Belém, PA, Brazil / Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Cultura de Tecidos. Ananindeua, PA, Brasil.Universidade Federal do Pará. Campus Universitário de Bragança. Instituto de Estudos Costeiros. Bragança, PA, Brazil.The Batrachoididae (Batrachoidiformes) is a diverse fish family (84 species) of considerable medical interest, responsible for large numbers of injuries in fishermen and bathers in northern Brazil. Batrachoides surinamensis (the Pacuma toadfish) is the most common Batrachoididae species in the Amazon coastal zone. The capacity of this species to adapt to the dynamic environment of estuaries, its sedentary behavior, and benthic spawning all contribute to the interest in this fish as a model for the study of patterns of chromosomal diversification. The present study investigated the chromosomal features of this species through conventional (Giemsa, C-banding, and Ag-NOR) and molecular (FISH mapping of the 18S and 5S rRNA, and the telomeric sequences) cytogenetic approaches. This is the first description of the karyotype of this species, which has a diploid number (2n) of 46 chromosomes (6m+8sm + 20st+12a) and a fundamental number (FN) of 80. All the chromosomes presented C-banding in the pericentromeric region. The AgNOR/18S rRNA sites were observed exclusively on the short arms of pair 13, whereas multiple 5S rRNA sites were found, on pairs 7 (submetacentric) and 20 (acrocentric). The telomeric probes revealed interstitial telomeric sequences (ITSs) in metacentric pair 3, indicating the occurrence of chromosome fusion. The karyotype of B. surinamensis presents a number of derived karyotypic features, and is differentiated primarily by its pericentric inversions and the apparent occurrence of at least one chromosome fusion event. The collection of additional cytogenetic data on other Batrachoididae species, and other populations of B. surinamensis, will provide further insights into the role of estuarine environments in the chromosomal diversification of this fish group