Chronotype and PERIOD3 Variable Number Tandem Repeat Polymorphism in Individual Sports Athletes

A link between diurnal preference and a variable number tandem-repeat (VNTR) polymorphism in the PERIOD3 gene (PER3) has been demonstrated: the longer PER3⁵ and shorter PER3⁴ alleles with preferences for mornings and evenings, respectively. As many competitive events in South Africa for individual athletes are scheduled for the early mornings, we hypothesized that this might favor those athletes with a preference for morning activities. Self-selected white, male cyclists (CYC, n = 125), runners (RUN, n = 120) and Ironman triathletes (IM, n = 287) of European descent were compared with a control population of active, non-competitive individuals (CON, n = 96). The chronotypes of all CYC, RUN and CON participants and a sub-sample of the IM group (n = 49) were assessed using the Horne–Östberg Morningness–Eveningness Questionnaire, and the PER3 VNTR genotype for each participant was determined. The athlete groups contained more morning-type individuals than the CON group (CYC: 72%, n = 90; RUN: 67%, n = 80; IM: 59%, n = 29; CON: 41%, n = 39; p < .001). The prevalence of the PER3⁵ allele was greater in the athlete groups (CYC: 61%, n = 152; RUN: 58%, n = 132; IM: 56%, n = 324; CON: 38%, n = 76; p < .001), and more athletes were genotyped as PER3^5/5 than CON individuals (CYC: 41%, n = 51; RUN: 23%, n = 26; IM: 28%, n = 81, CON: 9%, n = 8; p < .001). A strong relationship between chronotype and PER3 VNTR genotype was observed (p < .001). Finally, the time of day at which the athletes preferred to train was related to their chronotype (p < .001). This is the first study of its kind in a South African sporting population, and the results have not yet been replicated. These data suggest that white males of European descent participating in individual endurance sports in South Africa are more likely to be morning types. Furthermore, the PER3 VNTR may be one of the factors contributing to this observation. (Author correspondence: laura.roden@uct.ac.za)     

Association Study of a Variable-Number Tandem Repeat Polymorphism in the Clock Gene PERIOD3 and Chronotype in Norwegian University Students

Circadian rhythms are endogenously generated cycles involving physiological parameters, such as core body temperature, hormone levels, blood pressure, sleep, and metabolism, with a period length of around 24?h. The circadian clock in mammals is regulated by a set of clock genes that are functionally linked together, and polymorphisms in clock genes could be associated with differences in circadian rhythms. A variable-number tandem repeat (VNTR) in the human clock gene PERIOD3 (PER3) has been suggested to correlate with a morning (lark) versus evening (owl) chronotype as well as with the circadian rhythm sleep disorder “delayed sleep phase disorder” (DSPD). The authors examined 432 healthy Norwegian university students in search of further support for an association between the PER3 polymorphism and diurnal preference. The Horne-Östberg Morningness-Eveningness Questionnaire (MEQ) and Preferences Scale (PS) were used to evaluate subjective chronotype. DNA samples were genotyped with respect to the 4-repeat and 5-repeat alleles of the VNTR PER3 polymorphism, and the genotype distribution was 192 (4-4), 191 (4-5), and 49 (5-5). The authors estimated that the power to detect an association of the 4-allele with preference for morningness or eveningness was 75%. The authors found no association between the PER3 clock gene and chronotype, indicating that the proposed role of PER3 needs further clarification. (Author correspondence: teresa.osland@med.uib.no)     

South African populations of Littorina rudis

Littorina rudis was collected from stands of Spartina capensis in saltmarsh habitats within Langebaan and knysna lagoon, Cape Province. It was absent from rocky sores and from saltmarshes east of Knysna. The shell, radular and penial morphology are described. L. rudis from both localities bore tessellated colour patterns similar to those of British saltmarsh ecotypes. The Knysna population contained individuals with a unique amber background colour. The shells from Knysna and Langebaan were very thin in accordance with the sheltered habitats. The number of embryos carried in the brood puch was similar in both countries. Sexual maturity was attained at about 4 mm shell length; the male and female modal sizes were 4.9 mm and 5.1 mm respectively at Langebaan. No. published records were found for L. rudis in South West Africa. Some possible origins of the South African L. rudis populations are discussed.     

South African Museums and the Creation of a New National Identity

Museums are important sites of national cultural production, collective memory making, and the construction of national narratives. Contemporary South Africa is a particularly interesting place to study these processes. With the demise of apartheid, South Africa faces the difficult challenge of creating a new national identity that incorporates an examination of past oppression yet leaves the way open for building a national identity that incorporates all its diverse groups. The museums reviewed below, the Robben Island Prison Museum, the District Six Museum in Capetown, and the Kwa Muhle local history museum in Durban all make important contributions to this process.     

The biology of Dendropoma corallinaceum and Serpulorbis natalensis, two South African vermetid gastropods

D. corallinacewn forms sheet-like colonies at Mean Low Water (MLW) on exposed rocky shores: S. natalensis forms loose aggregations under stones below MLW in more sheltered situations. Both species released young from July— December. D. corallinaceun has single embryos in capsules brooded free in the mantle cavity; S. natalensis has 20–40 embryos per capsule, the latter being attached to the roof of the shell and hanging through a dorsal slit in the mantle. The morphology of the crawling young is similar in both species, resembling adult errant prosobranchs. D. corallinaceum has a stouter, more streamlined protoconch than S. natalensis correlated with the more turbulent water of its habitat. The crawling young secrete a sticky mucous trail for adhesion to the substratum. They are strongly photopositive until settlement. D. corallinaceum can settle within 24 hours but may delay settlement to 4–5 days if suitable substrata are absent. Metamorphosis is complete 2 days after settlement. D. corallinaceum prefer to settle on Lithothamnion which is easily eroded by the radula to provide a groove for rapid, firm attachments to the substratum. Both species feed from mucous nets, S. natalensis having a slower feeding rhythm commensurate with its larger size. Contiguous pairs of S. natalensis have synchronised feeding rhythms, probably to reduce mutual net robbing. Particles are also filtered out of suspension; many particles are rejected in the pseudofaeces but some are ingested. D. corallinaceum and S. natalensis have many similar ecologically equivalent species throughout the warm temperate and tropical seas of the world.     

On the genetic interrelationships of South African Negroes

This study addresses the comparative genetic interrelationships between South African Negro groups. For this the genetic distances between seven ethnically defined Negro subsamples (total of 998 individuals) based on 24 genetic loci/polymorphisms are calculated by applying standard distance formulae. These computations offer an opportunity to evaluate the different polymorphisms in terms of their effects on the genetic distances. The genetic interrelationships thus computed are illustrated by way of dendrograms and are discussed in terms of their comparative significance. It follows from the findings that the Ndebele, Northern Sotho (Pedi), and Tswana form a closely related subcluster and that the Zulu and Swazi as well as the Venda and Shangana-Tsonga form two additional, more distant, subclusters. These results are discussed and tentatively interpreted against the background of the reported Khoisan admixture of the populations concerned as well as their ethnological history. The data are also compared to those derived from metric and dermatoglyphic studies. It is concluded that whereas there is some agreement between these categories of variation (genetic, metric, and dermatoglyphic) as far as the comparative evaluation of South African Negro groups is concerned, there also are discrepancies. These conclusions need to be explained in terms of evolutionary mechanisms (such as historic origins, hybridization, natural selection, and genetic drift) in order to obtain a more consistent and comprehensive comparative picture of the physical anthropology of southern African populations.     

Taxonomic patterns of bleaching within a South African coral assemblage

In 1998, the Indian Ocean coral reefs suffered a severe and extensive mass bleaching event. The thermal tolerances of corals were exceeded and their photosynthetic symbionts (zooxanthellae) lost. Mortalities of up to 90% were recorded on the reefs of Seychelles, Maldives, Kenya and Tanzania. South African coral reefs were among the few that largely escaped the 1998 mass bleaching event, but may be threatened in the future if global warming increases. This study assessed the extent of coral bleaching and partial recovery at Sodwana Bay, South Africa during 2000 and 2001. Bleaching levels in this study varied over the course of a year, which suggested that seasonally varying parameters such as sea temperature were the most likely cause of bleaching. Bleaching levels were highest at the shallowest site. However, these bleaching levels were very low in comparison with those of reefs elsewhere in the Indian Ocean. The greater volume of water over the relatively deeper reefs of Sodwana Bay may have protected the reefs from severe bleaching. Field measurements on the three reefs indicated that, although the reefs at Sodwana Bay are still healthy, bleaching increased from <1% in 1998 to 5–10% in 2002. Bleaching occurred in 26 coral genera. The Alcyonacea were highly susceptible to bleaching, especially Sarcophyton sp. Among the hard corals, Montipora spp. were the species most susceptible to bleaching. The sensitivity of these genera to early and slight increases in temperature suggests that they can forewarn of a possible greater bleaching event. In contrast, the coral genera Turbinaria and Stylophora were most resistant to bleaching.     

Orphanhood and fertility in young adults: Evidence from South Africa

I study the relation between orphanhood and fertility patterns in young adults using a longitudinal survey from the city of Cape Town, South Africa. The data set combines two survey waves with a year-by-year life history calendar that records key outcomes (e.g., schooling, work, fertility). It also provides information on so-called ‘parental investments’ (time and material support), family background, and literacy and numeracy test scores. I find that orphans exhibit significantly higher rates of teenage pregnancy. In particular, teenage motherhood is 19% points more likely among (female) orphans. These results suggest that orphanhood may leave a long-lasting ‘imprint’ in terms of premature fertility, especially in teenage females.     

Desire Work: Producing Heterosexuality in South African Pentecostal Gay Men

Gay men in Cape Town, South Africa joined a Pentecostal ministry in an attempt to produce what they understood as ‘natural’ heterosexual attraction. In this article, I explore how these gay men try to form new selves through what I call ‘desire work’, or physical and emotional micropractices and discipline. Desire is not ‘natural’, but it is produced through a multitude of engagements with cultural norms, public life, political economies, and social forces. New selves are built through concerted bodily changes and comportment [Mahmood, Saba. 2005. Politics of Piety: The Islamic Revival and the Feminist Subject. Princeton, NJ: Princeton University Press], and although gay Pentecostal men shared this process, their success was limited. I understand desire work as a response to a larger context in which many Pentecostals are disaffected with the post-apartheid government and withdraw from politics as a result. Their fears of the uncertainties of democracy pushed them to engage in optimistic fantasies of heterosexual lives, which were not often realised [Berlant, Lauren Gail. 2011. Cruel Optimism. Durham, NC: Duke University Press].     

Sustainable dive ecotourism on a South African coral reef

SCUBA ecotourism provides economic support for local human communities and for conservation. Such support should be sustainable and as ecologically non-destructive as possible to its coral reef foundation. In recent years, the major increase in SCUBA activity has become a significant consideration at some locations. Among these are the South African coral reefs at Sodwana Bay, which receive 80 000 dives per year. Between May 1998 and January 1999, assessments using line-intercept and belt transects showed that 5.9% of hard corals and 4.0% of soft corals were damaged from various causes, while only 0.02% of the hard corals were dead. Of the 222 diver contacts observed, only 1.63% produced instant and visually-clear damage, with no measurable decline in overall coral reef health. Direct observations on 89 recreational divers showed that photographers made damaging contacts on nine out of ten dives, while novice divers made one such contact per six dives, moderately experienced divers about once every 14 dives, and very experienced divers about once every 123 dives. Increased time lapsed since the last dive increased diver damage by novices. We calculated that the 80 000 dives were equivalent to 1 m² of reef receiving 2.3 diver contacts per year. Acropora austera was by far the most significantly damaged coral, with one out of four branches broken per year. But as this species accounted for only 0.2% of reef benthos cover, this impact was not representative of overall reef health. This heavy species-specific impact makes A. austera a good bio-monitor.     

Biomass and production estimates of a fish community in a small South African estuary

The fish community of the small (17·5 ha) intermittently open East Kleinemonde estuary was sampled between 1994 and 1997 to estimate population size, standing stock, growth and productivity. The estuarine-spawning species were numerically more abundant ( n c . 750 000) but due to their small size contributed only 11·7% to the total biomass. The total annual productivity of all fishes in the estuary ( n c . 890 000), with a standing stock of 28·44 g m ⁻², was calculated at 55·89 g m⁻² year⁻¹. The small sparid Rhabdosargus holubi with a production estimate of 41·35 g m⁻² year⁻¹ accounted for <74% of the total fish production in this estuary.     

Fire and the chemistry of a South African mountain stream

The effects of a late-summer prescribed burn on the chemistry of a second-order mountain stream in the south-western Cape, South Africa, were investigated. Nitrate concentrations in stream water were significantly higher during the winter of the post-burn year. Increased concentrations of chloride, bicarbonate, polyphenols and potassium and decreased sodium concentrations were also recorded. Concentrations of ammonium, phosphate, calcium, magnesium, total dissolved solids and hydrogen ions were not significantly affected by the burn. Ionic export from the catchment was generally greater in the post-burn year. Apart from nitrate, however, values probably lie within the natural range of year-to-year variation. It is predicted that enhanced losses of nitrate will decrease progressively with the recovery of the vegetation and the re-establishment of soil/plant nutrient cycles. Atmospheric losses of nutrients in smoke were unquantified, but may be of more significance to site productivity than losses through surface runoff, which, in the case of nitrogen, appear to be compensated by precipitation inputs.     

Ecological and life-history correlates of cooperative breeding in South African birds

Our analyses of the incidence of cooperative breeding among South African birds differ from previous studies performed elsewhere in two respects. First, we distinguish between obligate (i.e. regular) and facultative (i.e. opportunistic) cooperative breeding species (OCS and FCS). Second, we have restricted our analyses to 217 South African bird species considered to be sufficiently well-studied in terms of their basic biology and life-history characteristics. This was done in order to control for the well-known bias against the often poorly-studied avifaunas of extreme environments such as rainforests and deserts. The results of our analysis do not accord fully with those of Australian birds by Ford et al. (1988). Cooperative breeding in South Africa is associated with seasonal environments, whereas in Australia the opposite is the case. Analyses of ecological factors that promote cooperative breeding among South African birds suggest that the evolutionary pathway to obligate and facultative breeding may be fundamentally different. First, OCS live mainly in savanna habitats that have predictable seasonal peaks in food availability, yet where the baseline level of food availability during the nonbreeding season is sufficient to support permanent residence by groups. Small to medium-sized birds of the African savannas are particularly vulnerable to avian predators, and foraging and roosting in permanent groups may enhance their survival. We propose that the benefits of obligate cooperative breeding are derived chiefly from survival of individuals away from the nest (i.e. during the nonbreeding season). Secondly, FCS live largely in unpredictable, seasonal steppe habitats. Under these conditions it may be impossible for birds to maintain permanent group territories, and variation in the tendency to breed cooperatively may depend largely on the opportunistic assessment of environmental conditions. We therefore suggest that birds (i.e. FCS) will opt to breed cooperatively only when conditions are unfavourable for independent breeding, and that the benefits thus accrued are chiefly related to reproduction.     

Recent changes in coral assemblages of a South African coral reef, with recommendations for long-term monitoring

Two-mile reef, Sodwana, South Africa is an unusual coral reef, being situated on a submerged fossilized sand dune and being very southerly (27°54). It is a popular Scuba diving venue receiving about 100000 dives year^–1. The line-intercept transect method, as recommended by the global coral reef monitoring network (GCRMN), was used to determine soft coral, hard coral and other benthos percentage cover. Physical coral damage, disease and bleaching were also recorded. Results were compared with those of B. Riegl (1993 – unpublished PhD thesis) 5 to 7 years earlier. The reef appears to be ecologically and highly dynamic. In the interim, there has been an increase in living benthos cover of 22.3% but also an increase in coral bleaching from 0% in 1993 to 1% in 1998. Physical damage, despite the large number of dives on the reef was minimal (1.52%), although it appears as if coral diseases may be increasing. The 20-m transects recommended by GCRMN are too long for this highly rugose reef with its distinct ridges and gullies. It is recommended that benthos cover, coral damage, bleaching and disease should be monitored annually using 40 5-m transects on the reef ridges and 40 5-m transects on the reef slopes.     

Ichthyofaunal assemblages in estuaries: A South African case study

This review places the life-history styles of fishes associated with South African estuaries in a global context and presents a classification system incorporating all the major life-history categories for estuary-associated fish species around the world. In addition, it documents the early life histories of the major fish groups in South African estuaries, with particular emphasis on the differing modes of estuarine utilization by marine, estuarine and freshwater taxa.This review details factors influencing the ichthyofaunal community structure in South African estuaries. The availability of fish for recruitment into an estuary depends primarily upon the distributional range of euryhaline marine and estuarine species, with tropical and temperate taxa showing marked abundance trends. Within a particular biogeographic region, however, estuarine type and prevailing salinity regime have a major influence on the detailed ichthyofaunal structure that develops. There is an increasing preponderance of marine fish taxa when moving from a freshwater-dominated towards a seawater-dominated type of system, and a decline in species diversity between subtropical estuaries in the north-east and cool temperate systems in the south-west. Similar declines in fish species diversity between tropical and temperate estuaries in other parts of the world are highlighted.Fish assemblages in estuaries adjust constantly in response to changing seasons, salinities, turbidities, etc. Despite persistent fluctuations in both the biotic and abiotic environment, the basic ichthyofaunal structure appears to have an underlying stability and to be predictable in terms of the response of individual species to specific conditions. This stability seems to be governed by factors such as the dominance of eurytopic taxa within estuarine assemblages and the robust nature of food webs within these systems. The predictability arises from factors such as the seasonality associated with estuarine spawning cycles and juvenile fish recruitment patterns. These patterns, together with a well-documented resilience to a wide range of physico-chemical and biotic perturbations, appear to be an underlying feature of fish assemblages in estuaries around the world.In contrast to marine fish species, estuary-associated taxa have received little conservation attention. Apart from the designation of protected areas, the main direct means of conserving estuary-associated fish stocks include habitat conservation and controls over fishing methods, effort, efficiency and seasonality. Of these, the conservation of fish habitats, the most important, because healthy aquatic environments invariably support healthy fish populations. The use of estuarine sanctuaries for fish conservation is briefly reviewed, as well as the legislation governing the USA National Estuarine Research Reserve System (NERRS) and the Australian Marine and Estuarine Protected Area (MEPA) system. It is concluded that South Africa requires an expansion of the existing Estuarine Protected Area (EPA) network, as well as the upgrading of selected 'estuarine reserves' where fishing is permitted, into 'estuarine sanctuaries' where no exploitation of biological resources is allowed.     

Biochemical polymorphisms in South African freshwater fish. Isoenzyme patterns in fish of the families Cyprinidae and Salmonidae

Isoenzyme patterns were studied in local populations of the carp ( Cyprinus carpio ) and the bream ( Sarotherodon mossambicus ) of the Cyprinid family. and in the trout ( Sabno giardneri ) of the family Salmonidae. Homogenates of heart muscle extracts were used in the identification of PGI. NADP-IDH. PGM and 6-PGD.
Polymorphisms found and gene frequencies obtained are discussed separately for each enzyme and species or population.
In the bream, variation was found only at the PGI locus. In the carp only the PGM locus was polymorphic whereas both PGM and IDH showed variation in the trout. The variation at the PGM locus in the trout cannot support the three locus model suggested elsewhere and clearly indicates a single locus for the mo-nomeric enzyme.
The large variety of NADP-IDH types in trout not only illucidates the complexity of this locus but confirms a disomic mode of inheritance. Genetic differences in the trout populations could be related to possible advantages for management purposes.     

Hydrochemical response during storm events in a South African mountain catchment: the influence of antecedent conditions

The influence of different antecedent conditions on hydrochemical response during storm events was investigated in a small, south-western Cape mountain catchment. Winter and summer storms (four in total) were sampled both before and after the catchment was deliberately burnt. During winter storms, discharge responded rapidly to rainfall, and direct runoff represented the major component of streamflow. Marked lags were observed between rainfall and discharge peaks during the summer storms, and streamflow was dominated by delayed interflow. Chloride, PO_inf4^sup3–-P and NO_inf3^sup–-N exhibited variable response to discharge according to seasonal variations in soil-moisture levels, whereas the response of HCO_inf3^sup–, H⁺ and NH_inf4^sup+-N was not influenced by season. The movement of ions appears to be affected more by geochemical processes operating within the soil than by plant-uptake dynamics, as the prescribed burn appeared to have little effect on relationships between ionic concentration and discharge. The findings of the study highlight the complexity of relationships between solute concentration and discharge.     

Physical growth in a transitional economy: the aftermath of South African apartheid

The economic transition in developing countries is not always the result of the change from a centrally-planned to a free-market economy, but may be found within an already existing free-market economy as a result of profound political change, as in South Africa. The release of Nelson Mandela in February 1990 heralded an end both to the political system of apartheid and to the concomitant social, political, and economic disenfranchisement of 30 million non-White people in South Africa. The first freely elected non-White government came to power in 1994 and initiated a number of social and economic reforms aimed at alleviating the worst consequences of apartheid. This paper examines the effect of post-apartheid economic and social transition on the growth and development of urban children. Over 4000 children born in Soweto and Johannesburg were enrolled in the Birth to Ten (BTT) birth-cohort study in 1990. Whilst these children were born with lower birth weights than in developed countries, they did grow strongly in infancy, particularly in weight, to reflect normal reference values for body mass index (BMI) by 1 year of age. While post-apartheid social and economic changes were expected to take some time to affect child growth and development, the rate of change has been slower than expected. Data from the BTT study demonstrate that the growth of White children continues to be superior to that of their non-White peers and differences that existed at birth and during infancy have not diminished during childhood and early adolescence. Whatever factors are changed at the national or community levels during economic (and social) transition in South Africa appear not yet to have resulted in improved child physical growth.     

Dental development in South African australopithecines. Part I: Problems of pattern and chronology

It is well known that humans take about twice as long as apes to mature. The traditional view that such delayed maturation was already present in australopithecines has been called into question during the past several years. We have approached this problem by looking at patterns of dental development in gracile and robust australopithecines from South Africa and comparing them to patterns found in extant humans and apes. We have employed both 2 and 3 dimensional computed tomography in our research. The dental growth patterns in these two australopithecine morphs differ, particularly in M1/I1 development. The robust australopithecines are more humanlike and the gracile australopithecines more apelike in this feature (“humanlike” and “apelike” are not used in any taxonomic sense). Pattern and chronology of dental development must be considered separately. Several major problem areas for future research are identified, most of which revolve around the issue of intra- versus interspecific variation.