Search results for "CHROMOSOME"
showing 10 items of 1175 documents
The Sea Urchin sns5 Chromatin Insulator Improves the Likelihood of Lentiviral Vectors in Erythroid Milieu By Organizing an Independent Chromatin Doma…
2015
Abstract Retroviral vectors are currently the most suitable vehicles for therapeutic gene transfer in hematopoietic stem cells. However, these vectors are known to integrate rather randomly throughout the genome, suffering the so called chromosomal position effects (PE). Such a critical occurrence most probably depends upon the ability of heterochromatin to spread in the inserted vector sequences. Moreover, the use of transgenes imply genotoxicity effects, since the cis-regulatory sequences harbored by the vector can disturb the proper transcription of the resident genes neighboring the integration site, potentially leading to malignant transformation. Due to their enhancer blocker activity…
Aneuploidy and Ethanol Tolerance in
2018
Response to environmental stresses is a key factor for microbial organism growth. One of the major stresses for yeasts in fermentative environments is ethanol. Saccharomyces cerevisiae is the most tolerant species in its genus, but intraspecific ethanol-tolerance variation exists. Although, much effort has been done in the last years to discover evolutionary paths to improve ethanol tolerance, this phenotype is still hardly understood. Here, we selected five strains with different ethanol tolerances, and used comparative genomics to determine the main factors that can explain these phenotypic differences. Surprisingly, the main genomic feature, shared only by the highest ethanol-tolerant st…
Imprint switching on human chromosome 15 may involve alternative transcripts of the SNRPN gene
1996
Imprinting on human chromosome 15 is regulated by an imprinting centre, which has been mapped to a 100–kb region including exon 1 of SNRPN. From this region we have identified novel transcripts, which represent alternative transcripts of the SNRPN gene. The novel exons lack protein coding potential and are expressed from the paternal chromosome only. We have also identified intragenic deletions and a point mutation in patients who have Angelman or Prader–Willi syndrome due to a parental imprint switch failure. This suggests that imprint switching on human chromosome 15 may involve alternative SNRPN transcripts.
Development of a quadruplex PCR system for the genetic analysis of X-chromosomal STR loci
2003
Short tandem repeat systems on the X chromosome are the natural counterpart to the well-established Y-chromosomal STR loci. The X-linked systems are inherited as a single haplotype only in males, whereas in females, the X chromosomes recombine and exhibit the same characteristics as the autosomes. Nevertheless, X-linked systems may provide a useful tool in paternity cases with female offspring, in particular when the alleged father is not available for testing, or in forensic identification cases based on the comparison with firstor second-degree relatives. Only a small number of STR loci have been described on the X chromosome, and a number of these are not highly informative. Therefore, w…
Temporal changes of chromosomal polymorphism in natural populations of Drosophila subobscura
1984
The behaviour of the chromosomal polymorphism of D. subobscura was analyzed in relation to temporal changes, daily, seasonal and annual. Firstly, chromosome analyses were carried out over a year in a natural population. Samples were taken at monthly intervals in Tibidabo, a locality close to Barcelona. In all the months except January, the number of individuals captured was enough to carry out a chromosome analysis of that population. The A, E and O chromosomes showed a great uniformity in the frequencies of gene arrangement over the year. However, significant changes occur in the frequencies of J and U chromosomes. The J1 and U1+2+8 arrangements showed a similar tendency, with two maxima, …
Analysis of male recombination in third chromosomes of Drosophila melanogaster
1983
Data on male recombination in twenty third-chromosomal lines of Drosophila melanogaster are presented. Frequencies of female and male recombination have been calculated in seven intervals along the third chromosome. The influence on male recombination (M.R.) exercised by different factors such as population origin (cellar, vineyard), the presence of heterozygous inversions and recessive lethal chromosomes, is analyzed. The results obtained lead to the main conclusion that M.R. is not affected by the presence of heterozygous inversions which reduce female recombination in the same lines. In the light of this effect, the possible mechanism operating on male recombination is discussed. Lethal …
Colonization of America by Drosophila subobscura: association between Odh gene haplotypes, lethal genes and chromosomal arrangements.
2004
The colonization of America by Drosophila subobscura has been a unique exper iment in nature that has allowed us to explore the effects of evolution on a continental scale. To analyze this evolutionary event, nucleotide sequences of the Odh (Octanol dehydrogenase) gene were obtained for 43 lethal chromosomal lines from colonizing populations of North America and 5 from South America, in addition to 5 chromosomal lines from Europe with different viabilities and 2 from laboratory marker stocks. Since 10 different Odh haplotypes were found in America, the minimum number of colonizers would be 5 (or 3 mated females). Only one Odh haplotype was found in American O(5) inversions confirming that o…
Study of eight novel Y-chromosome STRs in a sample from Valencia (East of Spain): analysis of gene and haplotypes frequencies
2003
Because of the great interest in Y-chromosome polymorphisms not only in the forensic field but also in evolutionary studies, the number of described Y-chromosome markers has been increased considerably in the recent literature. During the last few years, new Y-chromosome polymorphisms have been described, including binary polymorphisms, microsatellites and minisatellites. In this study, eight recently described tetranucleotide microsatellites have been analysed: DYS434, DYS437, DYS439, Y-GATA A7.1, Y-GATA A7.2, Y-GATA A.10, Y-GATA C4 and Y-GATA H4. Gene and haplotype frequencies have been estimated in the Valencian population, to determine highly informative haplotypes, using these new Y-ST…
Localization of amplified CAD genes on rearranged chromosomes of Chinese hamster cells
2012
Chinese hamster cell lines carrying an amplified CAD region were selected from V79,B7 cells by their resistance to N-phosphonacetyl-L-aspartate (PALA). In one of the selected cell lines, SP PALA (inf1) (supR) L, an acrocentric chromosome with abnormally elongated q arms was identified as a marker for the PALA-resistant phenotype. The marker chromosome carried a homogeneously staining region close to a telomeric nucleolar organizer region. In the same region, localization of amplified CAD sequences was demonstrated by in situ hybridization. The marker chromosome was found to undergo extensive rearrangements. In particular, dicentric chromosomes, occurring with an unusually high incidence, we…
Microsporogenesis in three wild species of the genusAntirrhinumL. (A. litigiosumPau,A. pulverulenthumLazaro andA. subbaeticumGüemes, Sánchez and Mate…
2010
The diploid chromosome number (2n = 2x = 16) in three wild species A. litigiosum Pau, A. pul- verulenthum Lazaro and A. subbaeticum Guemes, Sanchez & Mateu, belonging to the genus Antirrhinum was cytologically observed. Genetic stability of the simultaneous meiotic division type was found in these natural growing snapdragons. The synchronicity at the initial meiotic stages and at tetrad and pollen creation was high and disappeared with the diakinesis initiation. Refl ecting the systematic position of the studied species into Antirrhinum, the performed investigation mani- fested similarity: in the presence of univalents and quadrivalent confi gurations parallel with bivalents at the early me…