Tetraploidy can constitute a metastable intermediate between normal diploidy and oncogenic aneuploidy. Here, we show that the absence of p53 is not only permissive for the survival but also for multipolar asymmetric divisions of tetraploid cells, which lead to the generation of aneuploid cells with a near-to-diploid chromosome content. Multipolar mitoses (which reduce the tetraploid genome to a...

All somatic mammalian cells carry two copies of chromosomes (diploidy), whereas organisms with a single copy of their genome, such as yeast, provide a basis for recessive genetics. Here we report the generation of haploid mouse ESC lines from parthenogenetic embryos. These cells carry 20 chromosomes, express stem cell markers, and develop into all germ layers in vitro and in vivo. We also devel...

Conversion of diploidy to haploidy is a method that allows the generation of stable murine/human hybrid cell lines carrying selected human chromosomes in only a single copy. In this setting, it is possible to detect genetic mutations with greater sensitivity and reliability than in diploid cells. Using this method, we were able to identify mutations in the human mismatch repair (MMR) gene hMSH2...

Hyperdiploidy (>50 chromosomes, or a DNA index >1.16) confers a favorable prognosis in B-lineage acute lymphoblastic leukemia of childhood. Children with B-lineage acute lymphoblastic leukemia whose lymphoblasts at diagnosis accumulate high levels of methotrexate (MTX) and MTX polyglutamates (MTXPGs) in vitro experience a better eventfree survival than those whose lymphoblasts do not (Blood 76:...

Understanding the prevalence of sexual reproduction in eukaryotes is a hard problem. At least two aspects still defy a fully satisfactory explanation, the functional significance of genetic recombination and the great variation among taxa in the relative lengths of the haploid and diploid phases in the sexual cycle. We have performed an experimental study to explore the specific advantages of h...

Interspecific androgenetic rosy barb (Puntius conchonius) was generated using its cadaveric (-20 degrees C) or fresh sperm to activate nuclear genome inactivated oocytes of gray tiger barb (Puntius tetrazona). UV irradiation was used to inactivate nuclear genome of tiger barb oocytes. Thermal shock restored diploidy of rosy barb in the oocytes of tiger barb. Survival of androgenotes was 14% or ...

Drosophila melanogaster possesses a single gene, Dm myb, that is closely related to the vertebrate family of Myb genes, which encode transcription factors involved in regulatory decisions affecting cell proliferation, differentiation and apoptosis. In proliferating cells, the Dm myb gene product, DMyb, promotes both S-phase and M-phase, and acts to preserve diploidy by suppressing endoreduplica...

The Metamorphosis of Drug Research: DR. THEODORE Special Articles: G.KLUMPP......... nF..............................................................I.................... Chi panzeeHandedness: DR. GLEN FI Change from Self-Incompatibility to Self-CompatiAspects of Modern Psychology: DR. CHARLES S. bility Accompanying Change from Diploidy to MYERS . .. ................... ... .. . ...... .102 Tet...

Finding a compatible mating partner is an essential step in the life cycle of most sexually reproducing organisms. Fungi have two or more mating types, and only cells of different mating type combine to produce diploid cells. In mushrooms, this is taken to extremes, with the occurrence of many thousands of mating types. But, having gone to such extraordinary lengths to ensure that almost any tw...

The trade-off between growth rate and yield can limit population productivity. Here we tested for this life-history trade-off in replicate haploid and diploid populations of Saccharomyces cerevisiae propagated in glucose-limited medium in batch cultures for 5000 generations. The yield of single clones isolated from the haploid lineages, measured as both optical and population density at the end...