African Origins The modern human originated in Africa and subsequently spread across the globe. However, the genetic relationships among the diverse populations on the African continent have been unclear. Tishkoff et al. (p. 1035; see the cover, published online 30 April) provide a detailed genetic analysis of most major groups of African populations. The findings suggest that Africans represent 14 ancestral populations. Populations tend to be of mixed ancestry which documents historical migrations. The data mainly support but sometimes challenge proposed relationships between groups of self-identified ethnicity previously hypothesized on the basis of linguistic studies. The authors also examined populations of African Americans and individuals of mixed ancestry from Cape Town, documenting the variation and origins of admixture within these groups.

Quantifying patterns of population structure in Africans and African Americans illuminates the history of human populations and is critical for undertaking medical genomic studies on a global scale. To obtain a fine-scale genome-wide perspective of ancestry, we analyze Affymetrix GeneChip 500K genotype data from African Americans ( n = 365) and individuals with ancestry from West Africa ( n = 203 from 12 populations) and Europe ( n = 400 from 42 countries). We find that population structure within the West African sample reflects primarily language and secondarily geographical distance, echoing the Bantu expansion. Among African Americans, analysis of genomic admixture by a principal component-based approach indicates that the median proportion of European ancestry is 18.5% (25th–75th percentiles: 11.6–27.7%), with very large variation among individuals. In the African-American sample as a whole, few autosomal regions showed exceptionally high or low mean African ancestry, but the X chromosome showed elevated levels of African ancestry, consistent with a sex-biased pattern of gene flow with an excess of European male and African female ancestry. We also find that genomic profiles of individual African Americans afford personalized ancestry reconstructions differentiating ancient vs. recent European and African ancestry. Finally, patterns of genetic similarity among inferred African segments of African-American genomes and genomes of contemporary African populations included in this study suggest African ancestry is most similar to non-Bantu Niger-Kordofanian-speaking populations, consistent with historical documents of the African Diaspora and trans-Atlantic slave trade.

BackgroundThe Regional Committee for Africa of the World Health Organization (WHO) in 2001 expressed concern that some health-related studies undertaken in the Region were not subjected to any form of ethics review. In 2003, the study reported in this paper was conducted to determine which Member country did not have a national research ethics committee (REC) with a view to guiding the WHO Regional Office in developing practical strategies for supporting those countries.MethodsThis is a descriptive study. The questionnaire was prepared and sent by diplomatic pouch to all the 46 Member States in the WHO African Region, through the WHO country representatives, for facilitation and follow up. The data were entered in Excel spreadsheet and subsequently exported to STATA for analysis. A Chi-Squared test (χ2) for independence was undertaken to test the relationship between presence/absence of Research Ethics Committee (REC) and selected individual socioeconomic and health variables.ResultsThe main findings were as follows: the response rate was 61% (28/46); 64% (18/28) confirmed the existence of RECs; 36% (10/28) of the respondent countries did not have a REC (although 80% of them reported that they had in place an ad hoc ethical review mechanism); 85% (22/26) of the countries that responded to this question indicated that ethical approval of research proposals was, in principle, required; and although 59% of the countries that had a REC expected it to meet every month, only 44% of them reported that the REC actually met on a monthly basis. In the Chi-Squared test, only the average population in the group of countries with a REC was statistically different (at 5% level of significance) from that of the group of countries without a REC.ConclusionIn the current era of globalized biomedical research, good ethics stewardship demands that every country, irrespective of its level of economic development, should have in place a functional research ethics review system in order to protect the dignity, integrity and safety of its citizens who participate in research.

This report describes the purification and characterization from rat brain of triakontatetraneuropeptide (TTN, DBI 17-50), a major biologically active processing product of diazepam binding inhibitor (DBI). Brain TTN was purified by immunoaffinity chromatography with polyclonal octadecaneuropeptide, DBI 33-50) antibodies coupled to CNBr-Sepharose 4B followed by two reverse-phase HPLC steps. The amino acid sequence of the purified peptide is: Thr-Gln-Pro-Thr-Asp-Glu-Glu-Met-Leu-Phe-Ile-Tyr-Ser-His-Phe-Lys-Gln-Ala-Thr-Val - Gly-Asp-Val-Asn-Thr-Asp-Arg-Pro-Gly-Leu-Leu-Asp-Leu-Lys. Synthetic TTN injected intracerebroventricularly into rats induces a proconflict activity (IC50 0.8 nmol/rat) that is prevented by the specific "peripheral" benzodiazepine (BZ) receptor antagonist isoquinoline carboxamide, PK 11195, but not by the "central" BZ receptor antagonist imidazobenzodiazepine, flumazenil. TTN displaces [3H]Ro 5-4864 from synaptic membranes of olfactory bulb with a Ki of approximately 5 microM. TTN also enhances picrotoxinin inhibition of gamma-aminobutyric acid (GABA)-stimulated [3H]flunitrazepam binding. These data suggest that TTN, a natural DBI processing product acting at "Ro 5-4864 preferring" BZ binding site subtypes, might function as a putative neuromodulator of specific GABAA receptor-mediated effects.

Background: The World Health Organization (WHO) Regional Committee for Africa, in 1998, passed a resolution (AFR/RC48/R4) which urged its Member States in the Region to develop national research policies and strategies and to build national health research capacities, particularly through resource allocation, training of senior officials, strengthening of research institutions and establishment of coordination mechanisms.