The spatial distribution of parental genomes has attracted much interest because intranuclear chromosome distribution can modulate the transcriptome of cells and influence the efficacy of meiotic homologue pairing. Pairing of parental chromosomes is imperative to sexual reproduction as it translates into homologue segregation and genome haploidization to counteract the genome doubling at fertilization. Differential FISH tagging of parental pericentromeric genome portions and specific painting of euchromatic chromosome arms in Mus musculus (MMU) × Mus spretus (MSP) hybrid spermatogenesis disclosed a phase of homotypic non-homologous pericentromere clustering that led to parental pericentric genome separation from the pre-leptoteneup to zygotene stages. Preferential clustering of MMU pericentromeres correlated with particular enrichment of epigenetic marks (H3K9me3), HP1-γ and structural maintenance of chromosomes SMC6 complex proteins at the MMU major satellite DNA repeats. In contrast to the separation of heterochromatic pericentric genome portions, the euchromatic arms of homeologous chromosomes showed considerable presynaptic pairing already during leptotene stage of all mice investigated. Pericentric genome separation was eventually disbanded by telomere clustering that concentrated both parental pericentric genome portions in a limited nuclear sector of the bouquet nucleus. Our data disclose the differential behavior of pericentromeric heterochromatin and the euchromatic portions of the parental genomes during homologue search. Homotypic pericentromere clustering early in prophase I may contribute to the exclusion of large repetitive DNA domains from homology search, while the telomere bouquet congregates and registers spatially separated portions of the genome to fuel synapsis initiation and high levels of homologue pairing, thus contributing to the fidelity of meiosis and reproduction.Electronic supplementary materialThe online version of this article (doi:10.1007/s00412-014-0479-4) contains supplementary material, which is available to authorized users.
The Vocational Preference Inventory (VPI), 1985 revision, is a self-administered, brief paper-pencil, personality-interest inventory developed to "yield a broad range of information about interests, interpersonal relationships, values, self-conceptions, coping behaviors, and identifications" (Holland, 1985, p. 1). The VPI is designed for use with individuals with normal intelligence ages 14 through adult. The test consists of a list of 160 occupations which people indicate they are interested in by marking "Yes" and are disinterested in by marking "No." The test takes approximately 15 to 30 min to complete and score, according to the manual. The author cautions that the VPI should be "interpreted only in combination with other psychosocial information such as age, sex, educational level, field of training, and current occupational status" (p. 1). Although originally developed as a brief personality test, the VPI is primarily used as a way of assessing vocational interests. The test is based on Holland's six dimension model of vocational personalities: Realistic, Investigative, Artistic, Social, Enterprising, and Conventional (RIASEC; Holland, 1966). The typology codes are compatible with use of Holland's The Occupations Finder (1996) and the Dictionary of Holland Occupational Codes (Gottfredson & Holland, 1996).
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