Search results for "Hybridization"

Sequences homologous to the hobo transposable element in E strains of Drosophila melanogaster.

2001

Hobo is one of the three Drosophila melanogaster transposable elements, together with the P and I elements, that seem to have recently invaded the genome of this species. Surveys of the presence of hobo in strains from different geographical and temporal origins have shown that recently collected strains contain complete and deleted elements with high sequence similarity (H strains), but old strains lack hobo elements (E strains). Besides the canonical hobo sequences, both H and E strains show other poorly known hobo-related sequences. In the present work, we analyze the presence, cytogenetic location, and structure of some of these sequences in E strains of D. melanogaster. By in situ hybr…

Copy-number fluctuation by unequal crossing-over in the chicken avidin gene family.

2001

The chicken avidin gene (AVD) forms a closely clustered gene family together with several avidin-related genes (AVRs). In this study, we used fluorescence in situ hybridization on extended DNA fibers (fiber-FISH) to show that the number of the AVD and AVR genes differs between individuals. Furthermore, the gene copy-number showed wide somatic variation in white blood cells of the individuals. The molecular mechanism underlying the fluctuation is most probably unequal crossing-over and/or unequal sister chromatid exchange, as judged by the Gaussian distribution of the gene counts. By definition, an increase in gene number on one locus should be accompanied by a decrease on the other locus in…

Evaluation of different genetic procedures for the generation of artificial hybrids in Saccharomyces genus for winemaking

2012

Several methods based on recombinant DNA techniques have been proposed for yeast strain improvement; however, the most relevant oenological traits depend on a multitude of loci, making these techniques difficult to apply. In this way, hybridization techniques involving two complete genomes became interesting. Natural hybrid strains between different Saccharomyces species have been detected in diverse fermented beverages including wine, cider and beer. These hybrids seem to be better adapted to fluctuating situations typically observed in fermentations due to the acquisition of particular physiological properties of both parental strains. In this work we evaluated the usefulness of three dif…

Distribution of gypsy sequences in Drosophila species of the obscura subgroup.

2004

Eight Drosophila species of the obscura subgroup were screened for sequences homologous to the gypsy retrotransposon of D. melanogaster. Molecular characterization of gypsy sequences was first approached through digesting genomic DNAs from these obscura species with appropriate restriction enzymes and subjecting them to Southern blot analysis. The results of this analysis indicate that gypsy-homologous sequences are well conserved among species of the obscura subgroup. With the exception of D. guanche, all other species bear a 7 kb Xho I fragment that represents the complete element in D. melanogaster. Lower molecular weight fragments that could be deleted elements, are shared by different …

Cytogenetic characterization ofBrachidontes pharaonis(Fisher P., 1870): Karyotype, banding and fluorescentin situhybridization (fish) (Mollusca: Biva…

2000

Abstract The mussel Brachidontes pharaonis (Fisher P., 1870) (Bivalvia: Mytilidae) has a diploid chromosomal set of 28 made up of 14 pairs of which eight are mono-armed (ST) and six bi-armed (M+SM). Fourteen bivalents occur in spermatocytes both at pachytene and metaphase-I. The use of combined silver and CMA3 staining reveals that nucleolus organizer regions (NORs) are located terminally on the long arm of a small subtelocentric chromosome pair (pair 14) and are compartmentalized in GC base pairs. A Paracentrotus lividus (Echinodermata) 4.3 kilobase (kb) rDNA probe (prR14) consisting of sequences from the 3′ end of 18S rDNA to the 3′ end of 26S rDNA was used to map the rDNA loci of B. phar…

Assignment of enolase processed pseudogene (ENO1P) to human chromosome 1 bands 1q41→q42

1996

PCR-Typing of the Human HLA-DQα Locus: Population Genetics and Application in Forensic Casework

1991

Multi- and single-locus probes recognizing highly polymorphic DNA sequences throughout the genome ([1–3]; C. Rittner, this volume) have become powerful tools for paternity testing and forensic stain analysis. In forensic casework, however, DNA probe technology can often not be applied, since genomic DNA extracted from stain material exposed to conditions of high temperatures and humidity is degraded. Also, the amount of DNA to be typed may not be sufficient to use DNA probe technology, e.g. if extracted from minute blood or sperm stains, from single hairs or from cell smears on microscope slides.

Molecular biology approaches utilized in preimplantation genetics: real-time PCR, microarrays, next-generation sequencing, karyomapping, and others

2020

Abstract Over the past few decades the development of new molecular technologies has revolutionized diagnosis in the reproductive medicine field, with the evaluation of the two main factors involved in a successful pregnancy: the embryo and the endometrium. The detection of genetically abnormal embryos, as well as the identification of an optimum endometrium using transcriptomics have become a priority in assisted reproductive treatments to increase pregnancy rates. This chapter provides an overview of the molecular techniques currently employed in assisted reproduction for embryo evaluation such as preimplantation genetic testing karyotyping, fluorescence in situ hybridization, polymerase …

Exploring Evolution in Ceboidea (Platyrrhini, Primates) by Williams-Beuren Probe (HSA 7q11.23) Chromosome Mapping

2007

The ancestral platyrrhine karyotype was characterised by a syntenic association of human 5 and a small segment of human 7 orthologues. This large syntenic association has undergone numerous rearrangements in various phylogenetic lines. We used a locus-specific molecular cytogenetic approach to study the chromosomal evolution of the human 7q11.23 orthologous sequences (William-Beuren syndrome, WS) in various Ceboidea (Platyrrhini) species. The fluorescent in situ hybridisation of the WS probe revealed a two-way pattern of chromosomal organisation that suggests various evolutionary scenarios. The first pattern (seen in Callimico and Saimiri ) includes a fairly simple disruption of the 7/5 syn…

Cytogenetics in the sacoglossan Oxynoe olivacea (Mollusca: Opisthobranchia): karyotype, chromosome banding and fluorescent in situ hybridization

2000

Developing embryos and sexually mature follicles of the male portion of ovotestis proved to be a suitable material as a source of cleaving cells for advanced cytological investigations on the sacoglossan species Oxynoe olivacea Rafinesque, 1819 (Mollusca: Opisthobranchia). O. olivacea has a diploid chromosomal number of 30 made up of 15 pairs of which six are metacentric/submetacentric (M/SM), four subtelocentric (ST) and five on the borderline between SM and ST. Correspondingly, 15 bivalents occur in spermatocytes at Metaphase I. Constitutive heterochromatin is scarce and restricted to small C-bands seen in five pachytene bivalents. The use of combined silver staining and fluorescent in si…