The Sydney Declaration - An unique opportunity for Africa.

The Sydney Declaration (SD) has the inherent virtue of shifting the focus from the tools used in forensic science to the fundamental characteristics of appropriate forensic practice analysis of a situation and all related trace data for the purpose of resolving a case. Though several differences might be observed between countries regarding the technologies used, the fundamental principle of forensic logical reasoning are universally applicable to all contexts and environments and not only restricted to sophisticated, well-resourced, established forensic science laboratories based in countries that offer adequate resources, strong networks and legal frameworks. In Africa, several countries lack resources to train practitioners and to develop forensic science institutes, laboratories and other relevant institutions. The SD can serve as departure point to attain appropriate forensic science outcomes. Upholding its sound guidance can help forensic science practitioners remain faithful to their science, acknowledge their limits, give expert opinions based solely on facts and scientific analysis and interpretation, whilst also enhancing communication with their stakeholders. As forensic science develops in Africa, the SD presents a timely opportunity for us to proceed with a common understanding and a solid foundation through which our field can grow.

Ethical and practical issues to consider in the governance of genomic and human research data and data sharing in South Africa: a meeting report.

Genomic research and biobanking has undergone exponential growth in Africa and at the heart of this research is the sharing of biospecimens and associated clinical data amongst researchers in Africa and across the world. While this move towards open science is progressing, there has been a strengthening internationally of data protection regulations that seek to safeguard the rights of data subjects while promoting the movement of data for the benefit of research. In line with this global shift, many jurisdictions in Africa are introducing data protection regulations, but there has been limited consideration of the regulation of data sharing for genomic research and biobanking in Africa. South Africa (SA) is one country that has sought to regulate the international sharing of data and has enacted the Protection of Personal Information Act (POPIA) 2013 that will change the governance and regulation of data in SA, including health research data, once it is in force. To identify and discuss challenges and opportunities in the governance of data sharing for genomic and health research data in SA, a two-day meeting was convened in February 2019 in Cape Town, SA with over 30 participants with expertise in law, ethics, genomics and biobanking science, drawn from academia, industry, and government. This report sets out some of the key challenges identified during the workshop and the opportunities and limitations of the current regulatory framework in SA.

Characterization of the genetic variation present in CYP3A4 in three South African populations.

The CYP3A4 enzyme is the most abundant human cytochrome P450 (CYP) and is regarded as the most important enzyme involved in drug metabolism. Inter-individual and inter-population variability in gene expression and enzyme activity are thought to be influenced, in part, by genetic variation. Although Southern African individuals have been shown to exhibit the highest levels of genetic diversity, they have been under-represented in pharmacogenetic research to date. Therefore, the aim of this study was to identify genetic variation within CYP3A4 in three South African population groups comprising of 29 Khoisan, 65 Xhosa and 65 Mixed Ancestry (MA) individuals. To identify known and novel CYP3A4 variants, 15 individuals were randomly selected from each of the population groups for bi-directional Sanger sequencing of ~600 bp of the 5'-upstream region and all thirteen exons including flanking intronic regions. Genetic variants detected were genotyped in the rest of the cohort. In total, 24 SNPs were detected, including CYP3A4(*)12, CYP3A4(*)15, and the reportedly functional CYP3A4(*)1B promoter polymorphism, as well as two novel non-synonymous variants. These putatively functional variants, p.R162W and p.Q200H, were present in two of the three populations and all three populations, respectively, and in silico analysis predicted that the former would damage the protein product. Furthermore, the three populations were shown to exhibit distinct genetic profiles. These results confirm that South African populations show unique patterns of variation in the genes encoding xenobiotic metabolizing enzymes. This research suggests that population-specific genetic profiles for CYP3A4 and other drug metabolizing genes would be essential to make full use of pharmacogenetics in Southern Africa. Further investigation is needed to determine if the identified genetic variants influence CYP3A4 metabolism phenotype in these populations.

Compound heterozygosity in a South African patient with facioscapulohumeral muscular dystrophy.

Facioscapulohumeral muscular dystrophy (FSHD) is characterised by weakness and atrophy of the facial and shoulder girdle muscles. The FSHD phenotype segregates as an autosomal dominant trait and is caused by a deletion of an integral number of 3.3 kilobase pair (kb) repeat units on chromosome 4q35. Haplotype and Southern blot analyses of chromosome 4 resulted in the detection of two BlnI resistant deletion fragments, of 24 kb and 34 kb respectively, in a single individual from a South African FSHD family. The patient had moderate facial weakness and marked winging and high-riding of the scapulae with prominent pectoral and proximal arm muscle atrophy and weakness. Quadriceps and anterior tibial muscles were weak and the patient had bilateral foot drop. Although none of his children were symptomatic yet and only two showed very mild clinical signs, one had inherited the 24 kb deletion fragment, while the other two had the 34 kb deletion fragment. Molecular analysis conclusively identified the first compound heterozygous case in the South African FSHD population. However, in accordance with other studies of compound heterozygotes and clinical findings, no direct correlation between the clinical severity of this patient and the number of deletion fragments was observed.

Protective effect against type 2 diabetes mellitus identified within the ACDC gene in a black South African diabetic cohort.

Type 2 diabetes mellitus (T2D) is currently one of the fastest growing noncommunicable diseases in the world. It is induced by the pathogenic interaction between insulin resistance and secretion. This group of clinically heterogeneous disorders currently affects approximately 4% of the general population, but it is rapidly increasing, especially in developing regions such as sub-Saharan Africa. During this investigation, a diabetic (n = 227) and control cohort (n = 226) of adult black South African individuals were screened for the reported single nucleotide polymorphisms, termed C-11377G and G-11391A, within the promoter of the adiponectin (ACDC) gene. Genotyping was achieved via a real-time polymerase chain reaction method. It was determined that the variant allele at G-11391A as well as the 12 haplotype was significantly associated with a protective factor with regard to T2D susceptibility. The low frequency of this variant within the cohorts investigated indicated a minor role in decreasing disease susceptibility. It may not be a significant disease risk factor in itself, but may assist in elucidating the mechanism of disease susceptibility. When compared to various non-African populations, it becomes apparent that the investigated single nucleotide polymorphisms have differential effects depending on the population investigated. This investigation therefore underscores the genetic heterogeneity at T2D susceptibility loci within the black South African population.

Metallothionein isoform 2A expression is inducible and protects against ROS-mediated cell death in rotenone-treated HeLa cells.

The role of MT (metallothionein) gene expression was investigated in rotenone-treated HeLa cells to induce a deficiency of NADH:ubiquinone oxidoreductase (complex I). Complex I deficiency leads to a diversity of cellular consequences, including production of ROS (reactive oxygen species) and apoptosis. HeLa cells were titrated with rotenone, resulting in dose-dependent decrease in complex I activity and elevated ROS production at activities lower than 33%. Expression of MT2A (MT isoform 2A), but not MT1A or MT1B RNA, was significantly inducible by rotenone (up to 7-fold), t-BHP (t-butyl hydroperoxide; 5-fold) and CdCl2 (50-fold), but not ZnCl2. Myxothiazol treatment did not elevate either ROS or MT2A levels, which supports a ROS-related mechanism for rotenone-induced MT2A expression. To evaluate the role of MT2A expression, MT2A and MT1B were overexpressed in HeLa cells and treated with rotenone. Compared with control and MT1B-overexpressing cells, ROS production was significantly lower and cell viability higher in MT2A-overexpressing HeLa cells when ROS production was enhanced by treatment with t-BHP. Mitochondrial membrane potential was noticeably less reduced in both MT-overexpressing cell lines. MT2A overexpression in rotenone-treated cells also significantly reduced or delayed apoptosis induction, as measured by caspase 3/7 activity and cytosolic nucleosome enrichment. We conclude that MT2A offers significant protection against the main death-causing consequences of rotenone-induced complex I deficiency in HeLa cells. Our results are in support of the protective role against oxidative stress ascribed to MTs and provide evidence that MT2A expression may be a beneficial downstream adaptive response in complex I-deficient cells.

Natural selection shaped regional mtDNA variation in humans.

Human mtDNA shows striking regional variation, traditionally attributed to genetic drift. However, it is not easy to account for the fact that only two mtDNA lineages (M and N) left Africa to colonize Eurasia and that lineages A, C, D, and G show a 5-fold enrichment from central Asia to Siberia. As an alternative to drift, natural selection might have enriched for certain mtDNA lineages as people migrated north into colder climates. To test this hypothesis we analyzed 104 complete mtDNA sequences from all global regions and lineages. African mtDNA variation did not significantly deviate from the standard neutral model, but European, Asian, and Siberian plus Native American variations did. Analysis of amino acid substitution mutations (nonsynonymous, Ka) versus neutral mutations (synonymous, Ks) (kaks) for all 13 mtDNA protein-coding genes revealed that the ATP6 gene had the highest amino acid sequence variation of any human mtDNA gene, even though ATP6 is one of the more conserved mtDNA proteins. Comparison of the kaks ratios for each mtDNA gene from the tropical, temperate, and arctic zones revealed that ATP6 was highly variable in the mtDNAs from the arctic zone, cytochrome b was particularly variable in the temperate zone, and cytochrome oxidase I was notably more variable in the tropics. Moreover, multiple amino acid changes found in ATP6, cytochrome b, and cytochrome oxidase I appeared to be functionally significant. From these analyses we conclude that selection may have played a role in shaping human regional mtDNA variation and that one of the selective influences was climate.

A back migration from Asia to sub-Saharan Africa is supported by high-resolution analysis of human Y-chromosome haplotypes.

The variation of 77 biallelic sites located in the nonrecombining portion of the Y chromosome was examined in 608 male subjects from 22 African populations. This survey revealed a total of 37 binary haplotypes, which were combined with microsatellite polymorphism data to evaluate internal diversities and to estimate coalescence ages of the binary haplotypes. The majority of binary haplotypes showed a nonuniform distribution across the continent. Analysis of molecular variance detected a high level of interpopulation diversity (PhiST=0.342), which appears to be partially related to the geography (PhiCT=0.230). In sub-Saharan Africa, the recent spread of a set of haplotypes partially erased pre-existing diversity, but a high level of population (PhiST=0.332) and geographic (PhiCT=0.179) structuring persists. Correspondence analysis shows that three main clusters of populations can be identified: northern, eastern, and sub-Saharan Africans. Among the latter, the Khoisan, the Pygmies, and the northern Cameroonians are clearly distinct from a tight cluster formed by the Niger-Congo-speaking populations from western, central western, and southern Africa. Phylogeographic analyses suggest that a large component of the present Khoisan gene pool is eastern African in origin and that Asia was the source of a back migration to sub-Saharan Africa. Haplogroup IX Y chromosomes appear to have been involved in such a migration, the traces of which can now be observed mostly in northern Cameroon.