Y chromosome short arm-Sxr recombination in XSxr/Y males causes deletion of Rbm and XY female sex reversal.

We earlier described three lines of sex-reversed XY female mice deleted for sequences believed close to the testes-determining gene (Sry) on the Y chromosome short arm (Yp). The original sex-reversed females appeared among the offspring of XY males that carried the Yp duplication Sxr on their X chromosome. Earlier cytogenetic observations had suggested that the deletions resulted from asymmetrical meiotic recombination between the Y and the homologous Sxr region, but no direct evidence for this hypothesis was available. We have now analyzed the offspring of XSxr/Y males carrying an evolutionarily divergent Mus musculus domesticus Y chromosome, which permits detection and characterization of such recombination events. This analysis has enabled the derivation of a recombination map of Yp and Sxr, also demonstrating the orientation of Yp with respect to the Y centromere. The mapping data have established that Rbm, the murine homologue of a gene family cloned from the human Y chromosome, lies between Sry and the centromere. Analysis of two additional XY female lines shows that asymmetrical Yp-Sxr recombination leading to XY female sex reversal results in deletion of Rbm sequences. The deletions bring Sry closer to Y centromere, consistent with the hypothesis that position-effect inactivation of Sry is the basis for the sex reversal.

Functional haplodiploidy: a mechanism for the spread of insecticide resistance in an important international insect pest.

The coffee berry borer, Hypothenemus hampei, is the most important insect pest of coffee worldwide and has an unusual life history that ensures a high degree of inbreeding. Individual females lay a predominantly female brood within individual coffee berries and because males are flightless there is almost entirely full sib mating. We investigated the genetics associated with this interesting life history after the important discovery of resistance to the cyclodiene type insecticide endosulfan. Both the inheritance of the resistance phenotype and the resistance-associated point mutation in the gamma-aminobutyric acid receptor gene Rdl were examined. Consistent with haplodiploidy, males failed to express and transmit paternally derived resistance alleles. Furthermore, while cytological examination revealed that males are diploid, one set of chromosomes was condensed, and probably nonfunctional, in the somatic cells of all males examined. Moreover, although two sets of chromosomes were present in primary spermatocytes, the chromosomes failed to pair before the single meiotic division, and only one set was packaged in sperm. Thus, the coffee berry borer is "functionally" haplodiploid. Its genetics and life history may therefore represent an interesting intermediate step in the evolution of true haplodiploidy. The influence of this breeding system on the spread of insecticide resistance is discussed.

Oxidative DNA damage and senescence of human diploid fibroblast cells.

Human diploid fibroblast cells cease growth in culture after a finite number of population doublings. To address the cause of growth cessation in senescent IMR-90 human fibroblast cells, we determined the level of oxidative DNA damage by using 8-oxoguanine excised from DNA and 8-oxo-2'-deoxyguanosine in DNA as markers. Senescent cells excise from DNA four times more 8-oxoguanine per day than do early-passage young cells. The steady-state level of 8-oxo-2'-deoxyguanosine in DNA is approximately 35% higher in senescent cells than in young cells. Measurement of protein carbonyls shows that senescent cells did not appear to have elevated protein oxidation. To reduce the level of oxidative damage, we cultured cells under a more physiological O2 concentration (3%) and compared the replicative life span to the cells cultured at the O2 concentration of air (20%). We found that cells grown under 3% O2 achieved 50% more population doublings during their lifetime. Such an extension of life span resulted from the delayed onset of senescence and elevation of growth rate and saturation density of cells at all passages. The spin-trapping agent alpha-phenyl-t-butyl nitrone (PBN), which can act as an antioxidant, also effectively delayed senescence and rejuvenated near senescent cells. The effect is dose-dependent and is most pronounced for cells at the stage just before entry into senescence. Our data support the hypothesis that oxidative DNA damage contributes to replicative cessation in human diploid fibroblast cells.

High incidence of XXY and XYY males among the offspring of female chimeras from embryonic stem cells.

Injecting male embryonic stem cells into the blastocoel of female embryos occasionally produces female chimeras capable of transmitting the embryonic stem cell genome. In our experiments several embryonic stem cell-derived male offspring from female chimeras were observed to be infertile. Karyotypic analysis of these infertile animals revealed aneuploidy. We examined the karyotypes of an additional 14 offspring not selected for infertility (3 females and 11 males) that had received the embryonic stem cell genome from 5 transmitting female chimeras. The 3 females and 5 of the males had normal karyotypes. Six of the males exhibited nonmosaic aneuploidy, which included four XXY karyotypes, one XYY karyotype, and an X,i(Y) karyotype. The high incidence of XXY and XYY males supports previous evidence for aberrant pairing and segregation of X and Y chromosomes when they are present in oocytes.

Building Resilience in Young Black Males: Determining the Factors that Lead to Success for Black Men in America

It is no secret that Black men have struggled over the years to obtain the same level of high earning financial success as their White counterparts. Black men face an incredible challenge with regard to educational obtainment, career success, and physical health. Black men are often revered as the most dangerous, least educated, and more unhealthy than any other race or gender. This must change. This researcher investigated the lives of eight successful Black men with the hope of determining how they were able to attain their success. The findings of this research suggest that there are several factors that are key contributors in becoming a successful Black man in America. With a greater understanding of how Black men have managed to gain success, despite the obstacles they have faced, it is hopeful that this research will help other Black men reach the level of success that is often desired and seldom realized.

Fuerza de acción : males transitorios de los países latinoamericanos y modo de subsanarlos /

Mode of access: Internet.

Nuestros males universitarios; la universidad en la cultura, la sociedad y la moral.

Mode of access: Internet.

Prevalence and timing of oral sex with opposite-sex partners among females and males aged 15-24 years : United States, 2007-2010 /

Mode of access: Internet.

Libro intitulado Coloquios de la verdad, trata de las causas e inconvinientes que impiden la doctrina e conversión de los indios de los reinos del Pirú, y de los daños, e males, e agravios que padecen.

Includes bibliographical references.

The two roses, a farce in two acts for three males and two females.

Mode of access: Internet.

Educación política para establecer la libertad de los pueblos, ó sea los males y los remedios sobre la organización administrativa-social con un apéndice resúmen histórico de los borbones y de Pio IX /

Indice.

Los males y los remedios para las naciones civilizadas ó sea educacion política para establecer la libertad de los pueblos, basadas en las doctrinas y publicaciones de Mazzini, Victor Hugo, J. de la Portier, Garibaldi, Castelar, Cavour, Luis Blanch, Pí y Margall, Bismark, Figueras, Garrido, Ruiz Pons, Calvo Asensio, etc., etc. /

Indice.