Genetic variants determining survival and fertility in an adverse African environment: a population-based large-scale candidate gene association study.

Human survival probability and fertility decline strongly with age. These life history traits have been shaped by evolution. However, research has failed to uncover a consistent genetic determination of variation in survival and fertility.

Ancestral stories of Ghanaian Bimoba reflect millennia-old genetic lineages.

Oral history and oral genealogies are mechanisms of collective memory and a main cultural heritage of many populations without a writing system. In the effort to analytically address the correspondence between genetic data and historical genealogies, anthropologists hypothesised that genealogies evolve through time, ultimately containing three parts: literal--where the most recent ancestry is truthfully represented; intended--ancestry is inferred and reflects political relations among groups; and mythical--that does not represent current social reality. While numerous studies discuss oral genealogies, to our knowledge no genetic studies have been able to investigate to what extent genetic relatedness corresponds to the literal and intended parts of oral genealogies.

Indian Ocean crossroads: human genetic origin and population structure in the Maldives.

The Maldives are an 850 km-long string of atolls located centrally in the northern Indian Ocean basin. Because of this geographic situation, the present-day Maldivian population has potential for uncovering genetic signatures of historic migration events in the region. We therefore studied autosomal DNA-, mitochondrial DNA-, and Y-chromosomal DNA markers in a representative sample of 141 unrelated Maldivians, with 119 from six major settlements.

The influence of clan structure on the genetic variation in a single Ghanaian village.

Socioeconomic and cultural factors are thought to have an important role in influencing human population genetic structure. To explain such population structure differences, most studies analyse genetic differences among widely dispersed human populations. In contrast, we have studied the genetic structure of an ethnic group occupying a single village in north-eastern Ghana.

Mosaic segmental uniparental isodisomy and progressive clonal selection: a common mechanism of late onset β-thalassemia major.

Genomic DNA of 3 patients, born as healthy carriers and developing a late-onset severe transfusion-dependent beta-thalassemia major was studied by high-density genome wide SNP array analysis. A mosaic loss of heterozygosity for almost the entire 11p was found, not attributable to deletions but involving mosaicism for segmental paternal isodisomy of 11p. Mitotic recombination leading to mosaic segmental uniparental isodisomy on chromosome 11p in multiple tissues has been described as a molecular disease mechanism for a subset of sporadic Beckwith-Wiedemann syndrome cases.

Changed gene expression for candidate ageing genes in long-lived Bicyclus anynana butterflies.

Candidate genes for the regulation of lifespan have emerged from studies that use mutants and genetically manipulated model organisms. However, it is rarely addressed whether these genes contribute to lifespan variation in populations of these species that capture natural standing genetic variation. Here, we explore expression variation in three candidate ageing genes, Indy, sod2, and catalase, in Bicyclus anynana, a butterfly with well understood ecology.

Evaluating self-declared ancestry of U.S. Americans with autosomal, Y-chromosomal and mitochondrial DNA.

The current U.S. population represents an amalgam of individuals originating mainly from four continental regions (Africa, Europe, Asia and America).

A sensitive method to extract DNA from biological traces present on ammunition for the purpose of genetic profiling.

Exploring technological limits is a common practice in forensic DNA research. Reliable genetic profiling based on only a few cells isolated from trace material retrieved from a crime scene is nowadays more and more the rule rather than the exception. On many crime scenes, cartridges, bullets, and casings (jointly abbreviated as CBCs) are regularly found, and even after firing, these potentially carry trace amounts of biological material.

Potential constraints on evolution: sexual dimorphism and the problem of protandry in the butterfly Bicyclus anynana.

The earlier mean adult emergence between males and females, protandry, has been well studied mathematically and in comparative studies. However, quantitative and evolutionary genetic research on protandry is scarce. The butterfly, Bicyclus anynana exhibits protandry and here we selected for each of the different combinations of male and female development time in this species, thus including direct selection on protandry (i.

Increased life span in a polyphenic butterfly artificially selected for starvation resistance.

Starvation resistance is closely associated with fitness in natural populations of many organisms. It often co-varies with longevity and is a relevant target for understanding the evolution of aging. We selected for increased starvation resistance in the seasonally polyphenic butterfly Bicyclus anynana in a warm, wet-seasonal environment over 17 generations.

Developmental plasticity and acclimation both contribute to adaptive responses to alternating seasons of plenty and of stress in Bicyclus butterflies.

Plasticity is a crucial component of the life cycle of invertebrates that live as active adults throughout wet and dry seasons in the tropics. Such plasticity is seen in the numerous species of Bicyclus butterflies in Africa which exhibit seasonal polyphenism with sequential generations of adults with one or other of two alternative phenotypes. These differ not only in wing pattern but in many other traits.

Consequences of artificial selection on pre-adult development for adult lifespan under benign conditions in the butterfly Bicyclus anynana.

The genetic architecture underlying the regulation of lifespan is shaped by evolutionary history, thus, including selection in past environments. In particular, the developmental environment is important, because selection pressure for survival is highest during development. From this life-history point of view, the ageing phenotype is the outcome of these factors, and links between the developmental and adult life stage are expected.