Search results for "CHROMOSOME"

Patterns of puffing activity and chromosomal polymorphism in Drosophila subobscura : 3. Puffing activity depression by inbreeding.

1984

The effect of inbreeding on the puffing patterns of polytene chromosomes of Drosophila subobscura was analysed. Puffing activity was studied in two strains of D. subobscura: one which had been subject to inbreeding for 288 generations, and in the hybrids from a cross between them. A strong overall decrease in puffing activity was found in the inbred line. In general, hybrids behaved in a similar way to the inbred line or showed activity intermediate between the two lines. The fertility and viability of the two homozygous lines and of the hybrids were also determined. These parameters of fitness are very low in the inbred line. Hybrids displayed intermediate behaviour.

Chromosome 8p as a potential hub for developmental neuropsychiatric disorders: implications for schizophrenia, autism and cancer.

2009

Defects in genetic and developmental processes are thought to contribute susceptibility to autism and schizophrenia. Presumably, owing to etiological complexity identifying susceptibility genes and abnormalities in the development has been difficult. However, the importance of genes within chromosomal 8p region for neuropsychiatric disorders and cancer is well established. There are 484 annotated genes located on 8p; many are most likely oncogenes and tumor-suppressor genes. Molecular genetics and developmental studies have identified 21 genes in this region (ADRA1A, ARHGEF10, CHRNA2, CHRNA6, CHRNB3, DKK4, DPYSL2, EGR3, FGF17, FGF20, FGFR1, FZD3, LDL, NAT2, NEF3, NRG1, PCM1, PLAT, PPP3CC, S…

Chromosomal studies of five tropical scorpaeniform fishes (Teleostei, Scorpaenidae)

2003

Abstract The karyotypes of five species of Scorpaenidae (genera Scorpenopsis, Dendrochirus and Pterois) from the Indian Ocean were analysed using various banding methods and in situ hybridisation with a ribosomal probe. All the species investigated are characterised by a diploid set of 48 chromosomes (mainly acrocentric and/or subtelocentric) and by a NOR location on the small arm of a medium‐sized pair. All the chromosomes stained uniformly with DAPI, whereas C‐banding evidenced a small amount of hete‐rochromatin. Despite the marked morphological differences among these species, the low degree of diversification of the chromosome sets with respect to the ancestral set of teleosts (2n = 48 …

Artificial chromosome libraries of Streptomyces coelicolor A3(2) and Planobispora rosea

2003

Using an Escherichia coli-Streptomyces shuttle vector derived from a bacterial artificial chromosome (BAC), we developed methodologies for the construction of BAC libraries of filamentous actinomycetes. Libraries of Streptomyces coelicolor, the model actinomycete, and Planobispora rosea, a genetically intractable strain, were constructed. Both libraries have an average insert size of 60 kb, with maximal insert larger than 150 kb. The S. coelicolor library was evaluated by selected hybridisations to DraI fragments and by end sequencing of a few clones. Hybridisation of the P. rosea library to selected probes indicates a good representation of the P. rosea genome and that the library can be u…

Polymorphism and chromosomal localization of the porcine signal transducer and activator of transcription 5B gene (STAT5B).

2006

Signal transducers and activators of transcription (STATs) are a family of transcription factors. STAT5A and 5B are two highly related proteins encoded by two distinct genes. Transgenic knockout mice studies have indicated the importance of STAT5 proteins for the regulation of both lactation and growth performance. Moreover, different studies determine the role of STAT5 proteins in the modulation of adipocyte function. In this study, we sequenced one fragment of STAT5B gene from animals of six breeds (Duroc, Iberian, Landrace, Large White, Pie´train and Meishan) to identify genetic variants. A G/A single nucleotide polymorphism in intron 14 creates a polymorphic PstI restriction site and wa…

Assignment of signal transducer and activator of transcription 5A (STAT5A) to porcine chromosome 12p13→p11 by radiation hybrid panel mapping

2005

Intragenomic recombination between homologous regions of genes II and IV promotes formation of bacteriophage f1 miniphages.

1987

Mechanism for polarized recombination in Streptomyces.

1968

Recombination between pairs of mutations in a cluster of seven cistrons controlling histidine biosynthesis is highly polarized. The polarity is opposite at the opposite ends of the region. In experiments involving three his mutations it has been shown that recombination is the result of the transfer, from one parent to the other, of a segment going from the distal selected his+ allele to the end of the region. The rate of transfer is inversely proportional to the distance of the transferred his+ allele from the end of the region, at its side. A model of the process of recombination is discussed.

Plasmids in the aphid endosymbiont Buchnera aphidicola with the smallest genomes. A puzzling evolutionary story

2006

Buchnera aphidicola, the primary endosymbiont of aphids, has undergone important genomic and biochemical changes as an adaptation to intracellular life. The most important structural changes include a drastic genome reduction and the amplification of genes encoding key enzymes for the biosynthesis of amino acids by their translocation to plasmids. Molecular characterization through different aphid subfamilies has revealed that the genes involved in leucine and tryptophan biosynthesis show a variable fate, since they can be located on plasmids or on the chromosome in different lineages. This versatility contrasts with the genomic stasis found in three distantly related B. aphidicola strains …

Genetics of hepatocellular carcinoma.

2007

The completely assembled human genome has made it possible for modern medicine to step into an era rich in genetic information and high-throughput genomic analysis. These novel and readily available genetic resources and analytical tools may be the key to unravel the molecular basis of hepatocellular carcinoma (HCC). Moreover, since an efficient treatment for this disease is lacking, further understanding of the genetic background of HCC will be crucial in order to develop new therapies aimed at selected targets. We report on the current status and recent developments in HCC genetics. Special emphasis is given to the genetics and regulation of major signalling pathways involved in HCC such …