RESUMO
The genus Psammolestes within the subfamily Triatominae and tribe Rhodniini comprises the species Psammolestes arthuri, Psammolestes coreodes, and Psammolestes tertius, all potential vectors of Chagas disease. A feature of Psammolestes is their close association with birds, which makes them an interesting model for evolutionary studies. We analyzed cytogenetically Psammolestes spp., with the aim of contributing to the genetic and evolutionary knowledge of these vectors. All species of the Psammolestes showed the same chromosomal characteristics: chromocenter formed only by sex chromosomes X and Y, karyotype 2n = 22 and constitutive heterochromatin, and AT base pairs restricted to the sex chromosome Y. These results corroborate the monophyly of the genus and lead to the hypothesis that during the derivation of P. tertius, P. coreodes, and P. arthuri from their common ancestor, there was no reorganization in the number or structure of chromosomes.
Assuntos
Doença de Chagas/transmissão , Cromossomos de Insetos/química , Especiação Genética , Insetos Vetores/genética , Filogenia , Triatominae/genética , Animais , Pareamento de Bases , Aves/parasitologia , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Cromossomos de Insetos/ultraestrutura , Heterocromatina/química , Heterocromatina/ultraestrutura , Humanos , Insetos Vetores/classificação , Insetos Vetores/parasitologia , Cariótipo , América Latina/epidemiologia , Triatominae/classificação , Triatominae/parasitologia , Trypanosoma cruzi/patogenicidade , Cromossomo X/química , Cromossomo X/ultraestrutura , Cromossomo Y/química , Cromossomo Y/ultraestruturaRESUMO
To further explore Y-STR INRA189 polymorphisms in the yak, and to determine the genetic differences among yak breeds, genotyping analysis of INRA189 in 102 male yak individuals from three yak breeds in Qinghai Province of China was performed. Genotyping revealed the presence of four alleles, with sizes of 149, 155, 157, and 159 bp, respectively. Of these, the 157-bp allele, which was found with the highest frequency in the three yak breeds, was the dominant allele. Interestingly, the 149-bp allele was only detected in the Gaoyuan breed, and the 159-bp allele was only found in the Huanhu and Datong breeds. Only the 157- and 155-bp alleles were found in all three yak breeds. Taking the three yak breeds as a single population, the frequency of these four alleles was 0.0294, 0.0686, 0.8628, and 0.0392, respectively. The average polymorphism information content in the three yak breeds was 0.2379, indicating that the INRA189 was a low polymorphic Y-STR marker in yak.
Assuntos
Bovinos/genética , Cromossomos de Mamíferos/química , Marcadores Genéticos , Genoma , Polimorfismo Genético , Cromossomo Y/química , Alelos , Animais , Cruzamento , Bovinos/classificação , Feminino , Frequência do Gene , Loci Gênicos , Genótipo , Técnicas de Genotipagem , Masculino , FilogeniaRESUMO
Sperm dimensions and the question of whether X and Y chromosome-bearing sperm differ in size or shape has been of great interest, especially for the development of alternative methods to sort or classify sperm cells. The aim of the present study was to evaluate possible differences in the shape and size of the sperm head between X and Y chromosome-bearing sperm by atomic force microscopy (AFM). One ejaculate per bull (nâ=â4) was used. Each ejaculate was separated into four fractions: non-sexed (NS), sexed for X-sperm (SX), sexed for Y-sperm (SY) and a pooling of SX and SY samples (SXY). Using AFM, 400 sperm heads per group were measured. Twenty three structural features were assessed including one-, two- and three-dimensional parameters and shape descriptors. These measurements determine the micro- to nanoscale features of X- and Y-bearing chromosomes in sperm cells. No differences were observed for any individual variables between SX and SY groups. Next, a simultaneous evaluation of all features using statistical discriminant analysis was performed to determine if it was possible to distinguish to which group belong each individual cells. This analysis clearly showed, a distinct separation of NS, SXY, SX and SY groups. The recognition of this structural possibility to distinguish between X and Y sperm cell might improve the understanding of sperm cells biology. These results indicated that the associations of several structural measurements of the sperm cell head are promising candidates for development of a new method of sperm sexing.
Assuntos
Forma Celular/fisiologia , Tamanho Celular , Microscopia de Força Atômica/veterinária , Análise para Determinação do Sexo/métodos , Cabeça do Espermatozoide/ultraestrutura , Cromossomo X/química , Cromossomo Y/química , Animais , Bovinos , Separação Celular/métodos , Separação Celular/veterinária , Análise Discriminante , Modelos Lineares , Masculino , Microscopia de Força Atômica/métodos , Cabeça do Espermatozoide/químicaRESUMO
The identification of new bovine male-specific DNA sequences is of great interest because the bovine Y chromosome remains poorly characterized in terms of physical and genetic maps. Since taurine and zebu Y chromosomes are structurally different, the identification of Y-specific sequences present in both sub-species is particularly important: these sequences are of evolutionary significance and can be broadly used for embryo sexing. In this work, we initially used the random amplified polymorphic DNA (RAPD) technique to search for male-specific sequences present as monomorphic markers in genomic DNA from zebu and taurine bulls. A male-specific RAPD band was found to be present and highly conserved in both sub-species, as demonstrated by Southern blotting, fluorescent in situ hybridization (FISH) and DNA sequencing. In a previous work, a pair of primers derived from this marker was successfully used in taurine and zebu embryo sexing.
Assuntos
Bovinos/genética , Cromossomo Y/química , Animais , Sequência de Bases , Bison , Feminino , Marcadores Genéticos , Hibridização in Situ Fluorescente , Masculino , Técnica de Amplificação ao Acaso de DNA Polimórfico , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
The Y-chromatin is visualized in human interphase nuclei, corresponding to the distal portion of the Y-chromosome, which shows marked fluorescence after staining with quinacrine. This report describes the results of sex determination on blood smears fixed in methanol and blood stains left at room temperature for 13 weeks (1st report), and for 10 months (2nd report). Blind trials showed that a reliable sex determination of blood stains on glass left for at least six months is possible. The application of this method in forensic practice is discussed.