Variable patterns of Y chromosome homology in Akodontini rodents (Sigmodontinae): a phylogenetic signal revealed by chromosome painting

The Akodontini is the second most speciose tribe of sigmodontine rodents, one of the most diverse groups of neotropical mammals. Molecular phylogenetic analyses are discordant regarding the interrelationships of genera, with low support for some clades. However, two clades are concordant, one (clade A) with Akodon sensu strictu (excluding Akodon serrensis), "Akodon" serrensis, Bibimys, Deltamys, Juscelinomys, Necromys, Oxymycterus, Podoxymys, Thalpomys and Thaptomys, and another (clade B) with Blarinomys, Brucepattersonius, Kunsia, Lenoxus and Scapteromys. Here, we present chromosome painting using Akodon paranaensis (APA) Y paint, after suppression of simple repetitive sequences, on ten Akodontini genera. Partial Y chromosome homology, in addition to the homology already reported on the Akodon genus, was detected on the Y chromosomes of "A." serrensis, Thaptomys, Deltamys, Necromys and Thalpomys and on Y and X chromosomes in Oxymycterus. In Blarinomys, Brucepattersonius, Scapteromys and Kunsia, no APA Y signal was observed using different hybridization conditions; APA X paint gave positive signals only on the X chromosome in all genera. The Y chromosome homology was variable in size and positioning among the species studied as follow: (1) whole acrocentric Y chromosome in Akodon and "A." serrensis, (2) Yp and pericentromeric region in submetacentric Y of Necromys and Thaptomys, (3) pericentromeric region in acrocentric Y of Deltamys, (4) distal Yq in the acrocentric Y chromosome of Thalpomys and (5) proximal Yq in the acrocentric Y and Xp in the basal clade A genus Oxymycterus. The results suggest that the homology involves pairing (pseudoautosomal) and additional regions that have undergone rearrangement during divergence. The widespread Y homology represents a phylogenetic signal in Akodontini that provides additional evidence supporting the monophyly of clade A. The findings also raise questions about the evolution of the pseudoautosomal region observed in Oxymycterus. The Y chromosomes of these closely related species seem to have undergone dynamic rearrangements, including restructuring and reduction of homologous segments. Furthermore, the changes observed may indicate progressive attrition of the Y chromosome in more distantly related species.

Crossing over does occur in males of Drosophila ananassae from natural populations

Spontaneous crossing over in males of Drosophila ananassae has been well demonstrated using F-1 individuals from crosses between marker stocks and wild type strains. However, the question of its occurrence in males from natural populations remained open. Here we present the cytological evidence that crossing over does occur in males of D. ananassae from two Brazilian populations, sampled nearly 21 years apart, and in two recently sampled populations, one from Indonesia and one from Okinawa, Japan. Cytological analysis of meiosis in males collected from nature and in sons of females from the same population inseminated in nature revealed the presence of chiasmata, inversion chiasmata, and isosite chromosome breakages in the diplotene cells in all sampled populations. These data demonstrate that reciprocal and nonreciprocal exchanges and chromosome breakages, previously reported as related events of male crossing over, do occur at variable frequencies among males from natural populations.

Frontonasal dysplasia, callosal agenesis, basal encephalocele, and eye anomalies syndrome with a partial 21q22.3 deletion

We describe a girl with a phenotype characterized by frontonasal dysplasia, callosal agenesis, basal encephalocele, and eye anomalies who presents a 46,XX,r(21) karyotype. Array-comparative genomic hybridization using the Afflymetrix 100K DNA oligoarray set showed an interstitial deletion 21q22.3 of approximately 219?kb. Conventional karyotype of both parents was normal, and it was not possible to perform the molecular studies. In this report we raise the hypothesis that the deleted genes located at 21q22.3 could account to the phenotype. (C) 2012 Wiley Periodicals, Inc.

Osteosarcoma arising from osteochondroma of the tibia: case report and cytogenetic findings

Osteochondroma is a cartilage capped benign tumor developing mainly at the juxta-epiphyseal region of long bones. The rate of malignant transformation, mainly into chondrosarcoma, is estimated to be less than 1-3%. Transformation into osteosarcoma is very rare and has been reported only thirteen times. There is little information on treatment and outcome. We report the case of a secondary osteosarcoma arising in the left tibia of a 23-year-old male, 10 years after the initial diagnosis of osteochondroma and after two partial resections. Malignant transformation occurred at the stalk and not at the cartilage cap, as would normally be expected. Chromosome banding analysis revealed the karyotype: 46,XY, t(3;13)(q21;q34) [2]/46,XY [18]. Records from additional cases will help determine the parameters that define these rare secondary bone lesions.

Saethre-Chotzen phenotype with learning disability and hyper IgE phenotype in a patient due to complex chromosomal rearrangement involving chromosomes 3 and 7

The authors describe on a Brazilian girl with coronal synostosis, facial asymmetry, ptosis, brachydactyly, significant learning difficulties, recurrent scalp infections with marked hair loss, and elevated serum immunoglobulin E. Standard lymphocyte karyotype showed a small additional segment in 7p21[46,XX,add(7)(p21)]. Deletion of the TWIST1 gene, detected by Multiplex Ligation Probe-dependent Amplification (MPLA) and array-CGH, was consistent with phenotype of SaethreChotzen syndrome. Array CGH also showed deletion of four other genes at 7p21.1 (SNX13, PRPS1L1, HD9C9, and FERD3L) and the deletion of six genes (CACNA2D2, C3orf18, HEMK1, CISH, MAPKAPK3, and DOCK3) at 3p21.31. Our case reinforces FERD3L as candidate gene for intellectual disability and suggested that genes located in 3p21.3 can be related to hyper IgE phenotype. (C) 2012 Wiley Periodicals, Inc.

Is Drosera meristocaulis a pygmy sundew? Evidence of a long-distance dispersal between Western Australia and northern South America

South America and Oceania possess numerous floristic similarities, often confirmed by morphological and molecular data. The carnivorous Drosera meristocaulis (Droseraceae), endemic to the Neblina highlands of northern South America, was known to share morphological characters with the pygmy sundews of Drosera sect. Bryastrum, which are endemic to Australia and New Zealand. The inclusion of D. meristocaulis in a molecular phylogenetic analysis may clarify its systematic position and offer an opportunity to investigate character evolution in Droseraceae and phylogeographic patterns between South America and Oceania. was included in a molecular phylogenetic analysis of Droseraceae, using nuclear internal transcribed spacer (ITS) and plastid rbcL and rps16 sequence data. Pollen of D. meristocaulis was studied using light microscopy and scanning electron microscopy techniques, and the karyotype was inferred from root tip meristem. The phylogenetic inferences (maximum parsimony, maximum likelihood and Bayesian approaches) substantiate with high statistical support the inclusion of sect. Meristocaulis and its single species, D. meristocaulis, within the Australian Drosera clade, sister to a group comprising species of sect. Bryastrum. A chromosome number of 2n approx. 3236 supports the phylogenetic position within the Australian clade. The undivided styles, conspicuous large setuous stipules, a cryptocotylar (hypogaeous) germination pattern and pollen tetrads with aperture of intermediate type 78 are key morphological traits shared between D. meristocaulis and pygmy sundews of sect. Bryastrum from Australia and New Zealand. The multidisciplinary approach adopted in this study (using morphological, palynological, cytotaxonomic and molecular phylogenetic data) enabled us to elucidate the relationships of the thus far unplaced taxon D. meristocaulis. Long-distance dispersal between southwestern Oceania and northern South America is the most likely scenario to explain the phylogeographic pattern revealed.

Infantile Encephaloneuromyopathy and Defective Mitochondrial Translation Are Due to a Homozygous RMND1 Mutation

Defects of mitochondrial protein synthesis are clinically and genetically heterogeneous. We previously described a male infant who was born to consanguineous parents and who presented with severe congenital encephalopathy, peripheral neuropathy, myopathy, and lactic acidosis associated with deficiencies of multiple mitochondrial respiratory-chain enzymes and defective mitochondrial translation. In this work, we have characterized four additional affected family members, performed homozygosity mapping, and identified a homozygous splicing mutation in the splice donor site of exon 2 (c.504+1G>A) of RMND1 (required for meiotic nuclear division-1) in the affected individuals. Fibroblasts from affected individuals expressed two aberrant transcripts and had decreased wild-type mRNA and deficiencies of mitochondrial respiratory-chain enzymes. The RMND1 mutation caused haploinsufficiency that was rescued by overexpression of the wild-type transcript in mutant fibroblasts; this overexpression increased the levels and activities of mitochondrial respiratory-chain proteins. Knockdown of RMND1 via shRNA recapitulated the biochemical defect of the mutant fibroblasts, further supporting a loss-of-function pathomechanism in this disease. RMND1 belongs to the sif2 family, an evolutionary conserved group of proteins that share the DUF155 domain, have unknown function, and have never been associated with human disease. We documented that the protein localizes to mitochondria in mammalian and yeast cells. Further studies are necessary for understanding the function of this protein in mitochondrial protein translation.

Análise dos resultados maternos e fetais dos procedimentos invasivos genéticos fetais: um estudo exploratório em Hospital Universitário

OBJETIVO: Caracterizar as indicações das gestantes que procuraram o serviço de Medicina Fetal do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo para realização de procedimentos invasivos diagnósticos e avaliar os resultados dos cariótipos fetais e de suas gestações. MÉTODOS: Estudo observacional retrospectivo das gestantes que realizaram biópsia de vilo corial (BVC), amniocentese e cordocentese no período de fevereiro de 2005 a dezembro de 2009. Não foram incluídos outros procedimentos diagnósticos ou procedimentos terapêuticos. O resultado da gestação foi obtido através de consulta de prontuário eletrônico e/ou físico e/ou contato telefônico. RESULTADOS: Foram realizados 713 procedimentos (113 BVC, 340 amniocenteses e 260 cordocenteses). A principal indicação para a realização dos procedimentos invasivos foi a presença de alterações estruturais nos fetos, seguido por valores aumentados da translucência nucal e pela idade materna avançada. O cariótipo fetal esteve alterado em 186 casos (26,1%). A trissomia do cromossomo 18 foi a aneuploidia mais comum, seguida pela trissomia do 21, a monossomia do X e a trissomia do cromossomo 13. Ocorreram 4,9% de abortamento, 25,7% de natimortos e 13% de neomortos. Oito gestantes optaram pela interrupção judicial, e 99% das gestantes cujos fetos não apresentavam malformação e que apresentavam cariótipo fetal normal tiveram nativivos.

A new dic(7;12)(p12.21;p12.2) and i(12)(q10) during the lymphoid blast crisis of patient with Ph plus chronic myeloid leukemia

Chronic myelogenous leukemia (CML) is a common myeloproliferative disease that is characterized by the clonal expansion of marrow stem cells, and is associated with the Philadelphia chromosome. As the disease progresses, additional chromosome abnormalities may arise. The prognostic impact of secondary chromosomal abnormalities in CML is complex, heterogeneous, and sometimes related to previous treatment. Here, we describe a CML patient in lymphoid blast crisis associated with a new chromosomal abnormality identified, dic(7;12)(p12.21;p12.2) and i(12)(q10) using classical cytogenetics and spectral karyotype analysis. To the best of our knowledge, this is the first report of t(7;12)(p11.1;q11.1) and i(12)(q10) in a CML patient with lymphoid evolution.

Segmental dataset and whole body expression data do not support the hypothesis that non-random movement is an intrinsic property of Drosophila retrogenes

Background: Several studies in Drosophila have shown excessive movement of retrogenes from the X chromosome to autosomes, and that these genes are frequently expressed in the testis. This phenomenon has led to several hypotheses invoking natural selection as the process driving male-biased genes to the autosomes. Metta and Schlotterer (BMC Evol Biol 2010, 10:114) analyzed a set of retrogenes where the parental gene has been subsequently lost. They assumed that this class of retrogenes replaced the ancestral functions of the parental gene, and reported that these retrogenes, although mostly originating from movement out of the X chromosome, showed female-biased or unbiased expression. These observations led the authors to suggest that selective forces (such as meiotic sex chromosome inactivation and sexual antagonism) were not responsible for the observed pattern of retrogene movement out of the X chromosome. Results: We reanalyzed the dataset published by Metta and Schlotterer and found several issues that led us to a different conclusion. In particular, Metta and Schlotterer used a dataset combined with expression data in which significant sex-biased expression is not detectable. First, the authors used a segmental dataset where the genes selected for analysis were less testis-biased in expression than those that were excluded from the study. Second, sex-biased expression was defined by comparing male and female whole-body data and not the expression of these genes in gonadal tissues. This approach significantly reduces the probability of detecting sex-biased expressed genes, which explains why the vast majority of the genes analyzed (parental and retrogenes) were equally expressed in both males and females. Third, the female-biased expression observed by Metta and Schltterer is mostly found for parental genes located on the X chromosome, which is known to be enriched with genes with female-biased expression. Fourth, using additional gonad expression data, we found that autosomal genes analyzed by Metta and Schlotterer are less up regulated in ovaries and have higher chance to be expressed in meiotic cells of spermatogenesis when compared to X-linked genes. Conclusions: The criteria used to select retrogenes and the sex-biased expression data based on whole adult flies generated a segmental dataset of female-biased and unbiased expressed genes that was unable to detect the higher propensity of autosomal retrogenes to be expressed in males. Thus, there is no support for the authors' view that the movement of new retrogenes, which originated from X-linked parental genes, was not driven by selection. Therefore, selection-based genetic models remain the most parsimonious explanations for the observed chromosomal distribution of retrogenes.

Análise invasiva e não invasiva do fuso meiótico de oócitos humanos obtidos de ciclos estimulados: dados preliminares

OBJETIVOS: Avaliar a concordância entre as técnicas de microscopia de polarização e microscopia confocal na avaliação do fuso meiótico de oócitos humanos maturados in vivo. MÉTODOS: Estudo prospectivo que avaliou oócitos com o primeiro corpúsculo polar extruído obtidos de mulheres inférteis submetidas à estimulação ovariana para realização de injeção intracitoplasmática de espermatozoide. Os oócitos com o primeiro corpúsculo polar extruído foram avaliados por meio da microscopia de polarização e, imediatamente após, foram fixados e corados para avaliação dos microtúbulos e cromatina pela microscopia confocal de alto desempenho. Foram comparadas as técnicas de microscopia de polarização e confocal, de acordo com a visualização ou não do fuso meiótico pela microscopia de polarização e a presença ou não de anomalias meióticas à análise pela microscopia confocal. Foram calculados os intervalos de confiança, o índice de Kappa e a concordância entre as metodologias, considerando a análise da microscopia de imunofluorescência como padrão-ouro para avaliação de normalidade do fuso e distribuição cromossômica oocitária. RESULTADOS: Observou-se que 72,7% dos oócitos em metáfase II com fuso celular não visível à polarização apresentaram anormalidades meióticas à análise confocal e que 55,6% dos oócitos em metáfase II com fuso celular visível à polarização apresentaram-se como oócitos anormais à análise confocal. Somente 44,4% dos oócitos com fuso celular visível à polarização apresentaram-se como normais à análise confocal. A concordância entre os métodos foi de 51,1% (Kappa: 0,11; IC95% -0,0958 - 0,319). CONCLUSÕES: A baixa concordância entre a microscopia de polarização e a confocal na avaliação do fuso meiótico oocitário sugere que a visualização do fuso meiótico de oócitos humanos em metáfase II pela microscopia de polarização tem limitado o valor preditivo de normalidade meiótica oocitária.

Photobiological effect of low-level laser irradiation in bovine embryo production system

The objectives of this study were to evaluate the effect of low-level laser irradiation (LLLI) on bovine oocyte and granulosa cells metabolism during in vitro maturation (IVM) and further embryo development. Cumulus-oocytes complexes (COCs) were subjected (experimental group) or not (control group) to irradiation with LLLI in a 633-nm wavelength and 1 J/cm2 fluency. The COCs were evaluated after 30 min, 8, 16, and 24 h of IVM. Cumulus cells were evaluated for cell cycle status, mitochondrial activity, and viability (flow cytometry). Oocytes were assessed for meiotic progression status (nuclear staining), cell cycle genes content [real-time polymerase chain reaction (PCR)], and signal transduction status (western blot). The COCs were also in vitro fertilized, and the cleavage and blastocyst rates were assessed. Comparisons among groups were statistically performed with 5% significance level. For cumulus cells, a significant increase in mitochondrial membrane potential and the number of cells progressing through the cycle could be observed. Significant increases on cyclin B and cyclin-dependent kinase (CDK4) levels were also observed. Concerning the oocytes, a significantly higher amount of total mitogen-activated protein kinase was found after 8 h of irradiation, followed by a decrease in all cell cycle genes transcripts, exception made for the CDK4. However, no differences were observed in meiotic progression or embryo production. In conclusion, LLLI is an efficient tool to modulate the granulosa cells and oocyte metabolism