Association of apolipoprotein E polymorphism with plasma lipids and Alzheimer's disease in a Southern Brazilian population

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Genetic signatures of parental contribution in black and white populations in Brazil

Two hundred and three individuals classified as white were tested for 11 single nucleotide polymorphisms plus two insertion/deletions in their Y-chromosomes. A subset of these individuals (n = 172) was also screened for sequences in the first hypervariable segment of their mitochondrial DNA (mtDNA). In addition, complementary studies were done for 11 of the 13 markers indicated above in 54 of 107 black subjects previously investigated in this southern Brazilian population. The prevalence of Y-chromosome haplogroups among whites was similar to that found in the Azores (Portugal) or Spain, but not to that of other European countries. About half of the European or African mtDNA haplogroups of these individuals were related to their places of origin, but not their Amerindian counterparts. Persons classified in these two categories of skin color and related morphological traits showed distinct genomic ancestries through the country. These findings emphasize the need to consider in Brazil, despite some general trends, a notable heterogeneity in the pattern of admixture dynamics within and between populations/groups

Anatomical aspects of the embryo and initial development of Oenocarpus minor Mart: a palm tree from the Amazon

The anatomy of the embryo and the initial germination phase of O. minor seeds are examined here. Ripe fruits were collected from five individuals, the pulp removed, and the seeds sown in beds with sandy substrate in a greenhouse with 50% shade. Germination follow-up was made by collecting different stages of development. The anatomical study done according to usual techniques of light microscopy. The embryo is capitate and occupies a central position in the basal region of the seed. The embryogenic axis is located in the proximal region in a position that is oblique to the cotyledon axis. The cotyledon is formed by parenchymatous, procambial and protodermic tissue. The vascular bundles lie along the peripheral zone of the distal region to the embryogenicaxis. After 14 days, the primary rootemerges; after 21 days, the first cotyledon sheath and after 35 days, the second cotyledon sheath, and the seedling emerges above the substrate. Germination is of the ligule adjacent type.Neste trabalho foi feita a anatomia do embrião e a fase inicial da germinação da semente de O. minor. Frutos maduros de cinco indivíduos foram despolpados e as sementes obtidas foram semeadas em canteiros contendo substrato areia em casa de vegetação com sombreamento a 50%. O acompanhamento da germinação foi feito através de coletas das diferentes fases do desenvolvimento. O estudo anatômico foi realizado conforme técnicas usuais de microscopia de luz. O embrião é capitado. O eixo embrionário localiza-se na região proximal em posição oblíqua ao eixo cotiledonar. O cotilédone é formado por tecido parenquimático, procambial e protodérmico. Os feixes vasculares ocorrem ao longo da zona periférica da região distal até ao eixo embrionário. Aos 14 dias é emitida a raiz primária. Aos 21 dias forma-se a primeira bainha cotiledonar e aos 35 dias a segunda bainha cotiledonar ocorrendo à emergência da plântula acima do substrato. A germinação é do tipo adjacente ligular