PubMed · 5798738
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B Berelson, A F Guttmacher, B Viel. 1969. Population avalanche.. https://pubmed.ncbi.nlm.nih.gov/5798738/
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Schizophrenia is a complex psychiatric disorder, likely to be caused in part by multiple genes. In this study, linkage analyses were performed to identify chromosomal regions most likely to be associated with schizophrenia and psychosis in multiplex families of Mexican and Central American origin. Four hundred and fifty-nine individuals from 99 families, containing at least two siblings with hospital diagnoses of schizophrenia or schizoaffective disorder, were genotyped. Four hundred and four microsatellite markers were genotyped for all individuals and multipoint non-parametric linkage analyses were performed using broad (any psychosis) and narrow (schizophrenia and schizoaffective disorder) models. Under the broad model, three chromosomal regions (1pter-p36, 5q35, and 18p11) exhibited evidence of linkage with non-parametric lod (NPL) scores greater than 2.7 (equivalent to empirical P values of less than 0.001) with the peak multipoint NPL = 3.42 (empirical P value = 0.00003), meeting genomewide evidence for significant linkage in the 1pter-p36 region. Under the narrow model, the same three loci showed (non-significant) evidence of linkage. These linkage findings (1pter-p36, 18p11, and 5q35) highlight where genes for psychosis and schizophrenia are most likely to be found in persons of Mexican and Central American ancestry, and correspond to recent linkages of schizophrenia or psychosis in other populations which were formed in part from emigrants from the Spanish empire of the 15th and 16th centuries.
This study examines the population structure of Classic period (A.D. 250-900) Maya populations through analysis of odontometric variation of 827 skeletons from 12 archaeological sites in Mexico, Guatemala, Belize, and Honduras. The hypothesis that isolation by distance characterized Classic period Maya population structure is tested using Relethford and Blangero's (Hum Biol 62 (1990) 5-25) approach to R matrix analysis for quantitative traits. These results provide important biological data for understanding ancient Maya population history, particularly the effects of the competing Tikal and Calakmul hegemonies on patterns of lowland Maya site interaction. An overall F(ST) of 0.018 is found for the Maya area, indicating little among-group variation for the Classic Maya sites tested. Principal coordinates plots derived from the R matrix analysis show little regional patterning in the data, though the geographic outliers of Kaminaljuyu and a pooled Pacific Coast sample did not cluster with the lowland Maya sites. Mantel tests comparing the biological distance matrix to a geographic distance matrix found no association between genetic and geographic distance. In the Relethford-Blangero analysis, most sites possess negative or near-zero residuals, indicating minimal extraregional gene flow. The exceptions were Barton Ramie, Kaminaljuyu, and Seibal. A scaled R matrix analysis clarifies that genetic drift is a consideration for understanding Classic Maya population structure. All results indicate that isolation by distance does not describe Classic period Maya population structure.
The Latin American Cancer Research Coalition (LACRC) was funded by NCI as a Special Populations Network to 1) provide training to clinic staff in cancer control and foster development of Latino faculty training, 2) conduct a needs assessment with the community clinics, 3) enhance the ability of the clinics to promote healthy lifestyles, 4) collaborate on research projects to improve use of early detection, and 5) explore partnerships to increase access to culturally competent cancer care. The LACRC developed a model for cancer control focused on community-based clinics as the focal point for in-reach and community outreach targeted to Latinos to reduce cancer disparities. This framework was designed to link the community to local hospitals and academic centers, build capacity, and promote diffusion of innovations directly into delivery systems. Eight research projects submitted by junior investigator/clinic teams have been funded by NCI. These research projects range from recruiting for clinical trials to prevention to survivorship. The LACRC has trained 6 cancer control coordinators from partner sites and educated 59 undergraduate minority student interns in aspects of cancer control research. Central to LACRC's success to date has been the creation and maintenance of an infrastructure of trusting relationships, especially those developed between clinician/investigators and individuals within the greater Latino community. Community clinics can be effective agents for cancer control among Latinos. Latinos are likely to participate in research conducted by culturally representative teams of researchers using culturally appropriate recruiting strategies. Cancer 2006. (c) 2006 American Cancer Society.