Demographic History of Indigenous Populations in Mesoamerica Based on mtDNA Sequence Data

The genetic characterization of Native American groups provides insights into their history and demographic events. We sequenced the mitochondrial D-loop region (control region) of 520 samples from eight Mexican indigenous groups. In addition to an analysis of the genetic diversity, structure and genetic relationship between 28 Native American populations, we applied Bayesian skyline methodology for a deeper insight into the history of Mesoamerica. AMOVA tests applying cultural, linguistic and geographic criteria were performed. MDS plots showed a central cluster of Oaxaca and Maya populations, whereas those from the North and West were located on the periphery. Demographic reconstruction indicates higher values of the effective number of breeding females (Nef) in Central Mesoamerica during the Preclassic period, whereas this pattern moves toward the Classic period for groups in the North and West. Conversely, Nef minimum values are distributed either in the Lithic period (i.e. founder effects) or in recent periods (i.e. population declines). The Mesomerican regions showed differences in population fluctuation as indicated by the maximum Inter-Generational Rate (IGRmax): i) Center-South from the lithic period until the Preclassic; ii) West from the beginning of the Preclassic period until early Classic; iii) North characterized by a wide range of temporal variation from the Lithic to the Preclassic. Our findings are consistent with the genetic variations observed between central, South and Southeast Mesoamerica and the North-West region that are related to differences in genetic drift, structure, and temporal survival strategies (agriculture versus hunter-gathering, respectively). Interestingly, although the European contact had a major negative demographic impact, we detect a previous decline in Mesoamerica that had begun a few hundred years before

Diagnosis and follow-up of keratoacanthoma-like lesions: Clinical-histologic study of 43 cases

Background. Keratoacanthorna (KA) is easily confused with squamous cell carcinoma (SCC) on a clinical or a histopathologic basis. However, KA undergoes spontaneous regression, whereas SCC does not. Objective: Our objective was to study the histopathologic features associated with clinical regression in KA-like lesions to support the therapeutic option. Methods: Forty-three biopsies of KA-like lesions were taken at patient admission. One month later, surgical excision was performed in 18 growing lesions. Regressing lesions were left untreated. Classic histopathologic features and diagnosis were blindly recorded in both biopsies and surgical specimens. Results: On a clinical and a histologic basis, 32 lesions were assessed as KA and 11 as SCC. Features that indicated malignancy were observed in both groups, but the probability of SCC was 31 times higher in tumors with five or more of such features. Several of the histologically atypical lesions were found to regress. Conclusion: SCCs and KAs have more pathologic similarities than differences, especially in the proliferative phase. The combination of the most useful features did not allow the nosologic diagnosis in difficult cases but helped. Differential diagnosis was easier to determine after the 1-month follow up. Complete surgical excision should be indicated in nonregressing and growing lesions.12416317

Dialelo entre linhagens de uma população de pepino do tipo 'Caipira' Diallel among lines of a 'Caipira' type cucumber population

Este trabalho foi realizado para avaliar as capacidades geral e específica de combinação de seis linhagens de pepino 'Caipira', hibridizadas em um esquema dialélico, totalizando 15 híbridos experimentais (H-1 a H-15) possíveis (sem recíprocos). O delineamento foi em blocos ao acaso, com 23 tratamentos (6 linhagens, 15 híbridos experimentais e dois híbridos comerciais: 'Guarani' e 'Safira'), quatro repetições e 5 plantas por parcela. Foram avaliadas as seguintes características: número e massa total de frutos por planta, número e massa de frutos comerciais por planta e taxa de frutos comerciais. O híbrido 'H-5' foi o que apresentou as maiores heteroses para produção de frutos (45 a 51%), com produção comercial (em número de frutos por planta) superior a cinco linhagens e ao híbrido comercial 'Safira'. Tanto os efeitos aditivos como os não aditivos foram significativos para as características de produção de frutos (número e massa por planta), resultando em elevadas capacidades específicas de combinação para a maioria das combinações entre as linhagens. Das 75 estimativas de heterose obtidas, apenas três foram negativas.<br>The objective of this work was to evaluate general and specific combining ability of six 'Caipira' cucumber lines, hybridized in a diallel cross, totalizing 15 experimental hybrids (H-1 to H-15), without reciprocals. The experimental design was randomized blocks with 23 treatments (6 lines, 15 experimental hybrids and two commercial hybrids: 'Safira' and 'Guarani'), four replicates and 5 plants per plot. The following characteristics were evaluated: total fruit number and weight per plant, commercial fruit number and weight per plant and rate of commercial fruits. Hybrid H-5 showed the highest heterosis for fruit yield (45 to 51%), and had commercial yield (fruit number per plant) superior to five lines and to 'Safira' hybrid. Additive and non additive effects were significant for fruit yield (number and weight) per plant, resulting in high specific combining ability for most of lines combinations. From the 75 heterosis estimates, only three were negative

Capacidade combinatória e heterose de linhagens de pepino do grupo japonês para caracteres de produção.

O objetivo do trabalho foi estimar o efeito da capacidade geral (CGC) e específica (CEC) de combinação e a heterose de linhagens e populações de pepino japonês, empregando-se um topcross. Foram obtidos 16 híbridos experimentais a partir de duas populações testadoras (geração F2 de Yoshinari, TY, e de Natsusuzumi, TN) e oito linhagens S5 obtidas a partir do híbrido comercial Hokuho. Também foi avaliado o híbrido F1 Hokuho, totalizando 27 tratamentos. O delineamento experimental utilizado foi em blocos casualizados, com quatro repetições e cada parcela foi constituída de quatro plantas. Foram avaliadas as massas totais e comerciais, número de frutos total e comercial, porcentagem de frutos comerciais e massa média de frutos comerciais. A população de Yoshinari (TY) apresentou, em média, melhor capacidade de se combinar com as linhagens de Hokuho. A linhagem L7 apresentou os maiores valores positivos da estimativa da CGC para a maioria das características avaliadas. Os híbridos H1Y e H1N, que apresentavam a linhagem L1 como parental, foram os que apresentaram maiores valores para a estimativa da CEC com as populações testadoras para a maioria das características avaliadas, enquanto os que tinham a linhagem L5 como parental (H5Y e H5N) apresentaram os menores valores. A população F2 proveniente do híbrido Yoshinari apresentou, em geral, maior potencial de originar linhagens superiores para cruzamentos com linhagens de Hokuho, a fim de se obter híbridos com maior potencial produtivo. A heterose foi positiva para a grande maioria das características avaliadas.Made available in DSpace on 2011-04-09T16:08:19Z (GMT). No. of bitstreams: 1 2010JulianaPepino.pdf: 78466 bytes, checksum: 4df72bbdc05660b8463a899a03ea8f2b (MD5) Previous issue date: 2011-03-23201