Phylogenetic Distribution of Intron Positions in Alpha-Amylase Genes of Bilateria Suggests Numerous Gains and Losses

Most eukaryotes have at least some genes interrupted by introns. While it is well accepted that introns were already present at moderate density in the last eukaryote common ancestor, the conspicuous diversity of intron density among genomes suggests a complex evolutionary history, with marked differences between phyla. The question of the rates of intron gains and loss in the course of evolution and factors influencing them remains controversial. We have investigated a single gene family, alpha-amylase, in 55 species covering a variety of animal phyla. Comparison of intron positions across phyla suggests a complex history, with a likely ancestral intronless gene undergoing frequent intron loss and gain, leading to extant intron/exon structures that are highly variable, even among species from the same phylum. Because introns are known to play no regulatory role in this gene and there is no alternative splicing, the structural differences may be interpreted more easily: intron positions, sizes, losses or gains may be more likely related to factors linked to splicing mechanisms and requirements, and to recognition of introns and exons, or to more extrinsic factors, such as life cycle and population size. We have shown that intron losses outnumbered gains in recent periods, but that “resets” of intron positions occurred at the origin of several phyla, including vertebrates. Rates of gain and loss appear to be positively correlated. No phase preference was found. We also found evidence for parallel gains and for intron sliding. Presence of introns at given positions was correlated to a strong protosplice consensus sequence AG/G, which was much weaker in the absence of intron. In contrast, recent intron insertions were not associated with a specific sequence. In animal Amy genes, population size and generation time seem to have played only minor roles in shaping gene structures

Elderly widows' experience of sexuality and their perceptions regarding the family's opinion

O objetivo deste trabalho foi descrever a vivência da sexualidade por mulheres idosas viúvas, frequentadoras de um Centro de Convivência do Idoso, e verificar a percepção quanto à opinião dos seus familiares. Tratou-se de uma pesquisa qualitativa e exploratório-descritiva. Os dados foram coletados por meio de entrevistas semiestruturadas e submetidos à análise de conteúdo temática. Emergiram desta as categorias: 1) a vivência da sexualidade sofreu algumas modificações após o estado de viuvez garantindo submissão às normas e regras sociais para o comportamento feminino; 2) as idosas assumem ter optado pela vida sem um novo companheiro; 3) a família apoia o convívio social, mas não existe declaração de apoio para novos relacionamentos amorosos; e 4) houve ressignificação das questões de gênero no tocante às mudanças relativas ao papel social da mulher, depois da viuvez. Concluímos, portanto, que essas mulheres não vivem, de forma plena e livre, sua sexualidade, pois se submetem às normas sociais.The aim of this study was to describe the experience of sexuality of elderly widows attending an Elderly Community Centre and to verify their perceptions regarding their relatives' opinion. This was a qualitative and descriptive-exploratory research. Data were collected through semi-structured interviews and submitted to a thematic content analysis. The following categories emerged: 1) the experience of sexuality was modified after the women became widows, so that the female behavior complies with social norms and rules; 2) the elderly widows assume they have opted for life without a new partner; 3) the family supports social interaction, but there is no statement of support for new loving relationships; and 4) gender issues were redefined in relation to changes in the social role of women after widowhood. We conclude, therefore, that these women do not experience, neither fully nor freely, their sexuality, because they submit to the social norms

Bolivianos em São Paulo: entre o sonho e a realidade

ESTE ARTIGO tem como objetivo analisar o processo de inserção dos imigrantes bolivianos em São Paulo, focando as dificuldades enfrentadas por eles em suas trajetórias na cidade, bem como as estratégias de mobilidade econômica e de reconhecimento social, as quais vão sendo construídas num contexto adverso, marcado tanto pela indocumentação quanto pela discriminação racial e social.<br>THIS PAPER aims to analyze the settlement of Bolivian immigrants in São Paulo, focusing on the difficulties they face in their trajectories in the city, as well as on their strategies for economic mobility and social recognition, which are developed in an adverse environment characterized by lack of proper documentation and by racial and social discrimination