Molecular cytogenetics (FISH, GISH) of Coccinia grandis: A ca. 3 myr-old species of Cucurbitaceae with the largest Y/autosome divergence in flowering plants

The independent evolution of heteromorphic sex chromosomes in 19 species from 4 families of flowering plants permits studying X/Y divergence after the initial recombination suppression. Here, we document autosome/Y divergence in the tropical Cucurbitaceae Coccinia grandis, which is ca. 3 myr old. Karyotyping and C-value measurements show that the C. grandis Y chromosome has twice the size of any of the other chromosomes, with a male/female C-value difference of 0.094 pg or 10% of the total genome. FISH staining revealed 5S and 45S rDNA sites on autosomes but not on the Y chromosome, making it unlikely that rDNA contributed to the elongation of the Y chromosome; recent end-to-end fusion also seems unlikely given the lack of interstitial telomeric signals. GISH with different concentrations of female blocking DNA detected a possible pseudo-autosomal region on the Y chromosome, and C-banding suggests that the entire Y chromosome in C. grandis is heterochromatic. During meiosis, there is an end-to-end connection between the X and the Y chromosome, but the X does not otherwise differ from the remaining chromosomes. These findings and a review of plants with heteromorphic sex chromosomes reveal no relationship between species age and degree of sex chromosome dimorphism. Its relatively small genome size (0.943 pg/2C in males), large Y chromosome, and phylogenetic proximity to the fully sequenced Cucumis sativus make C. grandis a promising model to study sex chromosome evolution. Copyright © 2012 S. Karger AG, Base

Personality and repeated suicide attempts in dependent adolescents and young adults.

This study compared personality characteristics of subjects with dependence disorders who had previously made a suicide attempt. The population, recruited in France, Belgium, and Switzerland, was composed of 570 subjects (225 females, 345 males, mean age = 27.3, SD = 8.5). The subjects' psychological dimensions were investigated by means of several self-report questionnaires including: BDI-13 (Beck), Sensation-Seeking Scale (Zuckerman), Toronto Alexithymia Scale (Taylor), Interpersonal Dependency Inventory (Hirschfeld), MMPI-2, and some additional scales. For most dimensions, repeat attempters, both past and recent, but more specifically the recent repeaters, had a more severe psychological profile compared to the other suicide attempters

L'Auto-vélo : automobilisme, cyclisme, athlétisme, yachting, aérostation, escrime, hippisme / dir. Henri Desgranges

27 septembre 19431943/09/27 (A44,N15536)