Using multiple correspondence analysis to identify behaviour patterns associated with overweight and obesity in Vanuatu adults.

OBJECTIVE: The present study evaluates the use of multiple correspondence analysis (MCA), a type of exploratory factor analysis designed to reduce the dimensionality of large categorical data sets, in identifying behaviours associated with measures of overweight/obesity in Vanuatu, a rapidly modernizing Pacific Island country. DESIGN: Starting with seventy-three true/false questions regarding a variety of behaviours, MCA identified twelve most significantly associated with modernization status and transformed the aggregate binary responses of participants to these twelve questions into a linear scale. Using this scale, individuals were separated into three modernization groups (tertiles) among which measures of body fat were compared and OR for overweight/obesity were computed. SETTING: Vanuatu.ParticipantsNi-Vanuatu adults (n 810) aged 20-85 years. RESULTS: Among individuals in the tertile characterized by positive responses to most of or all the twelve modernization questions, weight and measures of body fat and the likelihood that measures of body fat were above the US 75th percentile were significantly greater compared with individuals in the tertiles characterized by mostly or partly negative responses. CONCLUSIONS: The study indicates that MCA can be used to identify individuals or groups at risk for overweight/obesity, based on answers to simply-put questions. MCA therefore may be useful in areas where obtaining detailed information about modernization status is constrained by time, money or manpower.

Ownership of consumer electronics is associated with measures of adiposity during health transition in Vanuatu.

OBJECTIVE: The Republic of Vanuatu, like many developing nations, is undergoing a rapid health transition. Our previous study identified several behavioral risk factors for the rising prevalence of obesity. Unexpectedly, daily time spent using television and radio was revealed as a protective factor for obesity in 2007. In this study, we sought to explore associations between ownership of consumer electronics (CE) and measures of adiposity in Vanuatu in 2011. METHODS: We surveyed 873 adults from five islands varying in level of economic development. Height, weight, and waist circumferences; triceps, subscapular, and suprailiac skinfolds; and percent body fat by bioelectrical impedance were measured. Ownership of eight types of CE, diet through 24-h dietary recall and leisure-time activity patterns were assessed using a questionnaire. RESULTS: Participants from more developed islands owned more types of CE, and revealed higher measures of adiposity on average as well as higher prevalence of obesity/central obesity. When controlling for demographic factors, and dietary and activity patterns, increased measures of adiposity and risk for obesity/central obesity were associated with ownership of cellphones, music players, televisions, video players, microwaves, and/or refrigerators. Positive correlations between CE ownership and measures of adiposity were mainly observed among men on the two most developed islands. CONCLUSIONS: The results of this study indicate a possible role of CE use in the rising prevalence of obesity and the shift to a sedentary lifestyle in Vanuatu and many other modernizing regions, where prevention efforts including education on healthy use of CE are imperative.

A prescription for sustaining community engagement in malaria elimination on Aneityum Island, Vanuatu: an application of Health Empowerment Theory.

BACKGROUND: Community engagement has contributed to disease control and elimination in many countries. Community engagement in malaria elimination (ME) on Aneityum Island has been sustained since its introduction in the early 1990s. Capacity developed within this population has led to a health empowered community response. Health Empowerment Theory (HET) can account for the innovative community actions and capacity development efforts taken to realize and sustain meaningful changes in well-being. This study used the HET framework to investigate participant perceptions of ME efforts on the island focusing on two HET elements, personal and social-contextual resources. The purpose of this study was to explore the role of empowerment as a critical element of community engagement. METHODS: Six focus group discussions, ten key informant interviews and 17 in-depth interviews were conducted in July 2012 on Aneityum. Both deductive and inductive approaches to qualitative content analysis were used to identify themes, which were condensed, coded and classified based on the HET elements above. RESULTS: Awareness and use of personal and social-contextual resources played an important role in ME efforts. Most participants shared their knowledge to prevent malaria reintroduction. Many participants reported their skills needed for behavioral maintenance, problem-solving or leadership. Participants who perceived a threat took preventive actions even in the dry season. Community leaders focused on second generation capacity development. A local health coalition provided ME services. Members of networks were sources of information and assistance. Face-to-face was the preferred method of communication. Barriers to engagement (e.g., financial difficulties, health literacy issues and underdeveloped infrastructure) were minimized through active collaboration and mutual assistance. CONCLUSIONS: In the community engagement continuum, health empowerment develops incrementally overtime as people gain their knowledge and skills, form coalitions and develop collaborative networks (social capital) to make decisions and take action for change. Community engagement, which facilitates local personal and social-contextual resource development, has potential for ME and multilevel empowerment through community-based capacity development processes. These self-empowered communities have written and will continue to write a 'prescription' for sustaining high levels of engagement.

Impact of modernization on adult body composition on five islands of varying economic development in Vanuatu.

OBJECTIVE: The Republic of Vanuatu, similar to other South Pacific island nations, is undergoing a rapid health transition as a consequence of modernization. The pace of modernization is uneven across Vanuatu's 63 inhabited islands, resulting in differential impacts on overall body composition and prevalence of obesity among islands, and between men and women. In this study, we investigated (1) how modernization impacts body composition between adult male and female Melanesians living on four islands of varying economic development in Vanuatu, and (2) how body composition differs between adult Melanesians and Polynesians living on rural islands in Vanuatu. METHODS: Anthropometric measurements were taken on adult male and female Melanesians aged 18 years and older (n = 839) on the islands of Ambae (rural), Aneityum (rural with tourism), Nguna (rural with urban access), and Efate (urban) in Vanuatu, in addition to Polynesian adults on Futuna (rural). RESULTS: Mean measurements of body mass and fatness, and prevalence of obesity, were greatest on the most modernized islands in our sample, particularly among women. Additionally, differences between men and women became more pronounced on islands that were more modernized. Rural Polynesians on Futuna exhibited greater body mass, adiposity, and prevalence of obesity than rural Melanesians on Ambae. CONCLUSIONS: We conclude that Vanuatu is undergoing an uneven and rapid health transition resulting in increased prevalence of obesity, and that women are at greatest risk for developing obesity-related chronic diseases in urbanized areas in Vanuatu.

Plasmodium vivax and Plasmodium falciparum at the crossroads of exchange among islands in Vanuatu: implications for malaria elimination strategies.

Understanding the transmission and movement of Plasmodium parasites is crucial for malaria elimination and prevention of resurgence. Located at the limit of malaria transmission in the Pacific, Vanuatu is an ideal candidate for elimination programs due to low endemicity and the isolated nature of its island setting. We analyzed the variation in the merozoite surface protein 1 (msp1) and the circumsporozoite protein (csp) of P. falciparum and P. vivax populations to examine the patterns of gene flow and population structures among seven sites on five islands in Vanuatu. Genetic diversity was in general higher in P. vivax than P. falciparum from the same site. In P. vivax, high genetic diversity was likely maintained by greater extent of gene flow among sites and among islands. Consistent with the different patterns of gene flow, the proportion of genetic variance found among islands was substantially higher in P. falciparum (28.81-31.23%) than in P. vivax (-0.53-3.99%). Our data suggest that the current island-by-island malaria elimination strategy in Vanuatu, while adequate for P. falciparum elimination, might need to be complemented with more centrally integrated measures to control P. vivax movement across islands.

Determinants of the use of insecticide-treated bed nets on islands of pre- and post-malaria elimination: an application of the health belief model in Vanuatu.

BACKGROUND: Insecticide-treated nets (ITNs) are an integral piece of any malaria elimination strategy, but compliance remains a challenge and determinants of use vary by location and context. The Health Belief Model (HBM) is a tool to explore perceptions and beliefs about malaria and ITN use. Insights from the model can be used to increase coverage to control malaria transmission in island contexts. METHODS: A mixed methods study consisting of a questionnaire and interviews was carried out in July 2012 on two islands of Vanuatu: Ambae Island where malaria transmission continues to occur at low levels, and Aneityum Island, where an elimination programme initiated in 1991 has halted transmission for several years. RESULTS: For most HBM constructs, no significant difference was found in the findings between the two islands: the fear of malaria (99%), severity of malaria (55%), malaria-prevention benefits of ITN use (79%) and willingness to use ITNs (93%). ITN use the previous night on Aneityum (73%) was higher than that on Ambae (68%) though not statistically significant. Results from interviews and group discussions showed that participants on Ambae tended to believe that risk was low due to the perceived absence of malaria, while participants on Aneityum believed that they were still at risk despite the long absence of malaria. On both islands, seasonal variation in perceived risk, thermal discomfort, costs of replacing nets, a lack of money, a lack of nets, nets in poor condition and the inconvenience of hanging had negative influences, while free mass distribution with awareness campaigns and the malaria-prevention benefits had positive influences on ITN use. CONCLUSIONS: The results on Ambae highlight the challenges of motivating communities to engage in elimination efforts when transmission continues to occur, while the results from Aneityum suggest the possibility of continued compliance to malaria elimination efforts given the threat of resurgence. Where a high degree of community engagement is possible, malaria elimination programmes may prove successful.

Complex polymorphisms in the Plasmodium falciparum multidrug resistance protein 2 gene and its contribution to antimalarial response.

Plasmodium falciparum has the capacity to escape the actions of essentially all antimalarial drugs. ATP-binding cassette (ABC) transporter proteins are known to cause multidrug resistance in a large range of organisms, including the Apicomplexa parasites. P. falciparum genome analysis has revealed two genes coding for the multidrug resistance protein (MRP) type of ABC transporters: Pfmrp1, previously associated with decreased parasite drug susceptibility, and the poorly studied Pfmrp2. The role of Pfmrp2 polymorphisms in modulating sensitivity to antimalarial drugs has not been established. We herein report a comprehensive account of the Pfmrp2 genetic variability in 46 isolates from Thailand. A notably high frequency of 2.8 single nucleotide polymorphisms (SNPs)/kb was identified for this gene, including some novel SNPs. Additionally, we found that Pfmrp2 harbors a significant number of microindels, some previously not reported. We also investigated the potential association of the identified Pfmrp2 polymorphisms with altered in vitro susceptibility to several antimalarials used in artemisinin-based combination therapy and with parasite clearance time. Association analysis suggested Pfmrp2 polymorphisms modulate the parasite's in vitro response to quinoline antimalarials, including chloroquine, piperaquine, and mefloquine, and association with in vivo parasite clearance. In conclusion, our study reveals that the Pfmrp2 gene is the most diverse ABC transporter known in P. falciparum with a potential role in antimalarial drug resistance.

Characterization of ancient DNA supports long-term survival of Haloarchaea.

Bacteria and archaea isolated from crystals of halite 10(4) to 10(8) years old suggest long-term survival of halophilic microorganisms, but the results are controversial. Independent verification of the authenticity of reputed living prokaryotes in ancient salt is required because of the high potential for environmental and laboratory contamination. Low success rates of prokaryote cultivation from ancient halite, however, hamper direct replication experiments. In such cases, culture-independent approaches that use the polymerase chain reaction (PCR) and sequencing of 16S ribosomal DNA are a robust alternative. Here, we use amplification, cloning, and sequencing of 16S ribosomal DNA to investigate the authenticity of halophilic archaea cultured from subsurface halite, Death Valley, California, 22,000 to 34,000 years old. We recovered 16S ribosomal DNA sequences that are identical, or nearly so (>99%), to two strains, Natronomonas DV462A and Halorubrum DV427, which were previously isolated from the same halite interval. These results provide the best independent support to date for the long-term survival of halophilic archaea in ancient halite. PCR-based approaches are sensitive to small amounts of DNA and could allow investigation of even older halites, 10(6) to 10(8) years old, from which microbial cultures have been reported. Such studies of microbial life in ancient salt are particularly important as we search for microbial signatures in similar deposits on Mars and elsewhere in the Solar System.

Behavioral risk factors for obesity during health transition in Vanuatu, South Pacific.

UNLABELLED: The South Pacific archipelago of Vanuatu, like many developing countries, is currently experiencing a shift in disease burdens from infectious to chronic diseases with economic development. A rapid increase in obesity prevalence represents one component of this "health transition." OBJECTIVE: To identify behaviors associated with measures of obesity in Vanuatu. DESIGN AND METHODS: Five hundred and thirty four adults from three islands varying in level of economic development were surveyed. Height, weight, waist, and hip circumferences; triceps, subscapular and suprailiac skinfolds; and percent body fat (%BF) by bioelectrical impedance were measured. Diet through 24-h dietary recall and physical activity patterns using a survey were assessed. We analyzed prevalence of obesity and central obesity based on multiple indicators (body mass index, %BF, waist circumference, and waist-to-height ratio), and analyzed differences among islands and associations with behavioral patterns. RESULTS: Obesity prevalence was lowest among rural and highest among suburban participants. Prevalence of central obesity was particularly high among women (up to 73.9%), even in rural areas (ranging from 14.7 to 41.2% depending on the measure used). Heavier reliance on animal protein and incorporation of Western foods in the diet-specifically, tinned fish and instant noodles-was significantly associated with increased obesity risk. CONCLUSIONS: Even in rural areas where diets and lifestyles remain largely traditional, modest incorporation of Western foods in the diet can contribute to increased risk of obesity. Early prevention efforts are thus particularly important during health transition. Where public health resources are limited, education about dietary change could be the best target for prevention.

The origins and genetic distinctiveness of the Chamorros of the Marianas Islands: an mtDNA perspective.

BACKGROUND: Archaeological and linguistic evidence suggests the Marianas Islands were settled around 3,600 years before present (ybp) from Island Southeast Asia (ISEA). Around 1,000 ybp latte stone pillars and the first evidence of rice cultivation appear in the Marianas. Both traditions are absent in the rest of prehistoric Oceania. OBJECTIVE: To examine the genetic origins and postsettlement gene flow of Chamorros of the Marianas Islands. METHODS: To infer the origins of the Chamorros we analyzed ∼360 base pairs of the hypervariable-region 1 (HVS1) of mitochondrial DNA from 105 Chamorros from Guam, Rota, and Saipan, and the complete mitochondrial genome of 32 Guamanian Chamorros, and compared them to lineages from ISEA and neighboring Pacific archipelagoes from the database. RESULTS: Results reveal that 92% of Chamorros belong to haplogroup E, also found in ISEA but rare in Oceania. The two most numerous E lineages were identical to lineages currently found in Indonesia, while the remaining E lineages differed by only one or two mutations and all were unique to the Marianas. Seven percent of the lineages belonged to a single Chamorro-specific lineage within haplogroup B4, common to ISEA as well as Micronesia and Polynesia. CONCLUSIONS: These patterns suggest a small founding population had reached and settled the Marianas from ISEA by 4,000 ybp, and developed unique mutations in isolation. A second migration from ISEA may have arrived around 1,000 ybp, introducing the latte pillars, rice agriculture and the homogeneous minority B4 lineage.

Diversity of Plasmodium falciparum chloroquine resistance transporter (pfcrt) exon 2 haplotypes in the Pacific from 1959 to 1979.

Nearly one million deaths are attributed to malaria every year. Recent reports of multi-drug treatment failure of falciparum malaria underscore the need to understand the molecular basis of drug resistance. Multiple mutations in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) are involved in chloroquine resistance, but the evolution of complex haplotypes is not yet well understood. Using over 4,500 archival human serum specimens collected from 19 Pacific populations between 1959 and 1979, the period including and just prior to the appearance of chloroquine treatment failure in the Pacific, we PCR-amplified and sequenced a portion of the pfcrt exon 2 from 771 P. falciparum-infected individuals to explore the spatial and temporal variation in falciparum malaria prevalence and the evolution of chloroquine resistance. In the Pacific, the prevalence of P. falciparum varied considerably across ecological zones. On the island of New Guinea, the decreases in prevalence of P. falciparum in coastal, high-transmission areas over time were contrasted by the increase in prevalence during the same period in the highlands, where transmission was intermittent. We found 78 unique pfcrt haplotypes consisting of 34 amino acid substitutions and 28 synonymous mutations. More importantly, two pfcrt mutations (N75D and K76T) implicated in chloroquine resistance were present in parasites from New Hebrides (now Vanuatu) eight years before the first report of treatment failure. Our results also revealed unexpectedly high levels of genetic diversity in pfcrt exon 2 prior to the historical chloroquine resistance selective sweep, particularly in areas where disease burden was relatively low. In the Pacific, parasite genetic isolation, as well as host acquired immune status and genetic resistance to malaria, were important contributors to the evolution of chloroquine resistance in P. falciparum.

Patterns of childhood and adolescent overweight and obesity during health transition in Vanuatu.

OBJECTIVE: Rapid economic development and subsequent changes in lifestyle and disease burdens ('health transition') is associated with increasing prevalence of obesity among both adults and children. However, because of continued infectious diseases and undernutrition during the early stages of transition, monitoring childhood obesity has not been prioritized in many countries and the scope of the problem is unknown. Therefore we sought to characterize patterns of childhood overweight and obesity in an early transitional area, the South Pacific archipelago of Vanuatu. DESIGN: We completed an anthropometric survey among children from three islands with varying levels of economic development, from rural areas (where adult obesity prevalence is low) to urban areas (where adult obesity prevalence is high). SETTING: The islands of Ambae (rural), Aneityum (rural with tourism) and Efate (urban). SUBJECTS: Boys and girls (n 513) aged 6-17 years. RESULTS: Height-, weight- and BMI-for-age did not vary among islands, and prevalence of overweight/obesity based on BMI was low. However, girls from Aneityum - a rural island where the tourism industry increased rapidly after malaria eradication - had increased central adiposity compared with girls from the other islands. This is contrary to adult patterns, which indicate higher obesity prevalence in urban areas. Multiple factors might contribute, including stunting, biological responses after malaria control, sleeping patterns, diet and physical activity levels. CONCLUSIONS: Measures of central adiposity highlight an emerging obesity risk among girls in Vanuatu. The data highlight the synergistic relationship among infectious diseases, undernutrition and obesity during the early stages of health transition.

Ancient microbes from halite fluid inclusions: optimized surface sterilization and DNA extraction.

Fluid inclusions in evaporite minerals (halite, gypsum, etc.) potentially preserve genetic records of microbial diversity and changing environmental conditions of Earth's hydrosphere for nearly one billion years. Here we describe a robust protocol for surface sterilization and retrieval of DNA from fluid inclusions in halite that, unlike previously published methods, guarantees removal of potentially contaminating surface-bound DNA. The protocol involves microscopic visualization of cell structures, deliberate surface contamination followed by surface sterilization with acid and bleach washes, and DNA extraction using Amicon centrifugal filters. Methods were verified on halite crystals of four different ages from Saline Valley, California (modern, 36 ka, 64 ka, and 150 ka), with retrieval of algal and archaeal DNA, and characterization of the algal community using ITS1 sequences. The protocol we developed opens up new avenues for study of ancient microbial ecosystems in fluid inclusions, understanding microbial evolution across geological time, and investigating the antiquity of life on earth and other parts of the solar system.

Behavioral changes associated with economic development in the South Pacific: health transition in Vanuatu.

UNLABELLED: Health patterns are changing in developing countries; as diet and activity patterns change with economic development, chronic disease prevalence increases, which is a characteristic of health transition. The islands of Vanuatu (South Pacific) have varying rates of economic development and provide a natural experimental model of health transition. OBJECTIVES: To characterize behavioral changes associated with modernization. METHODS: We surveyed 425 children and 559 adults on three islands varying in degree of economic development. We assessed diet (24-h dietary recall), physical activity (mode of transport, work activities, and recreation), substance use, and other behavioral patterns. RESULTS: Spending patterns and access to Western foods followed modernization gradients in our sample, whereas occupational patterns and ownership of technological goods were poor markers of modernization. With increasing economic development, participants consumed more animal proteins and simple carbohydrates. Physical activity levels were high; most participants were active in gardening, and sports were popular, especially in urban areas. However, urban participants spent more time in sedentary recreation. Men's use of alcohol and tobacco increased with economic development, but we observed marked differences in substance use patterns between two rural islands-one with and one without tourism. CONCLUSIONS: Economic development in Vanuatu is accompanied by nutrition transition and increased sedentary recreation, although physical activity levels remain high. Differences in substance use patterns between rural islands with and without tourism indicate a need for more research in rural areas. These findings might inform research in other communities in the early stages of health transition.

Characterizing genetic diversity of contemporary pacific chickens using mitochondrial DNA analyses.

BACKGROUND: Mitochondrial DNA (mtDNA) hypervariable region (HVR) sequences of prehistoric Polynesian chicken samples reflect dispersal of two haplogroups--D and E--by the settlers of the Pacific. The distribution of these chicken haplogroups has been used as an indicator of human movement. Recent analyses suggested similarities between prehistoric Pacific and South American chicken samples, perhaps reflecting prehistoric Polynesian introduction of the chicken into South America. These analyses have been heavily debated. The current distribution of the D and E lineages among contemporary chicken populations in the Western Pacific is unclear, but might ultimately help to inform debates about the movements of humans that carried them. OBJECTIVES: We sought to characterize contemporary mtDNA diversity among chickens in two of the earliest settled archipelagos of Remote Oceania, the Marianas and Vanuatu. METHODS: We generated HVR sequences for 43 chickens from four islands in Vanuatu, and for 5 chickens from Guam in the Marianas. RESULTS: Forty samples from Vanuatu and three from Guam were assigned to haplogroup D, supporting this as a Pacific chicken haplogroup that persists in the Western Pacific. Two haplogroup E lineages were observed in Guam and two in Vanuatu. Of the E lineages in Vanuatu, one was identical to prehistoric Vanuatu and Polynesian samples and the other differed by one polymorphism. Contrary to our expectations, we observed few globally distributed domesticate lineages not associated with Pacific chicken dispersal. This might suggest less European introgression of chickens into Vanuatu than expected. If so, the E lineages might represent lineages maintained from ancient Pacific chicken introductions. The Vanuatu sample might thus provide an opportunity to distinguish between maintained ancestral Pacific chicken lineages and replacement by global domesticates through genomic analyses, which could resolve questions of contemporary haplogroup E chicken relationships and inform interpretations of debated sequences from archaeological samples.

Associations between dopamine D4 receptor gene variation with both infidelity and sexual promiscuity.

BACKGROUND: Human sexual behavior is highly variable both within and between populations. While sex-related characteristics and sexual behavior are central to evolutionary theory (sexual selection), little is known about the genetic bases of individual variation in sexual behavior. The variable number tandem repeats (VNTR) polymorphism in exon III of the human dopamine D4 receptor gene (DRD4) has been correlated with an array of behavioral phenotypes and may be predicatively responsible for variation in motivating some sexual behaviors, particularly promiscuity and infidelity. METHODOLOGY/PRINCIPAL FINDINGS: We administered an anonymous survey on personal history of sexual behavior and intimate relationships to 181 young adults. We also collected buccal wash samples and genotyped the DRD4 VNTR. Here we show that individuals with at least one 7-repeat allele (7R+) report a greater categorical rate of promiscuous sexual behavior (i.e., having ever had a "one-night stand") and report a more than 50% increase in instances of sexual infidelity. CONCLUSIONS/SIGNIFICANCE: DRD4 VNTR genotype varies considerably within and among populations and has been subject to relatively recent, local selective pressures. Individual differences in sexual behavior are likely partially mediated by individual genetic variation in genes coding for motivation and reward in the brain. Conceptualizing these findings in terms of r/K selection theory suggests a mechanism for selective pressure for and against the 7R+ genotype that may explain the considerable global allelic variation for this polymorphism.

Relationships between body size and percent body fat among Melanesians in Vanuatu.

Obesity is a global epidemic, and measures to define it must be appropriate for diverse populations for accurate assessment of worldwide risk. Obesity refers to excess body fatness, but is more commonly defined by body mass index (BMI). Body composition varies among populations: Asians have higher percent body fat (%BF), and Pacific Islanders lower %BF at a given BMI compared to Europeans. Many researchers thus propose higher BMI cut-off points for obesity among Pacific Islanders and lower cut-offs for Asians. Because of the great genetic diversity in the Asia-Pacific region, more studies analyzing associations between BMI and %BF among diverse populations remain necessary. We measured height; weight; tricep, subscapular, and suprailiac skinfolds; waist and hip circumference; and %BF by bioelectrical impedance among 546 adult Melanesians from Vanuatu in the South Pacific. We analyzed relationships among anthropometric measurements and compared them to measurements from other populations in the Asia-Pacific region. BMI was a relatively good predictor of %BF among our sample. Based on regression analyses, the BMI value associated with obesity defined by %BF (>25% for men, >35% for women) at age 40 was 27.9 for men and 27.8 for women. This indicates a need for a more nuanced definition of obesity than provided by the common BMI cut-off value of 30. Rather than using population-specific cut-offs for Pacific Islanders, we suggest the World Health Organization's public health action cut-off points (23, 27.5, 32.5, 37.5), which enhance the precision of assessments of population-wide obesity burdens while still allowing for international comparison.

Assortative human pair-bonding for partner ancestry and allelic variation of the dopamine receptor D4 (DRD4) gene.

The 7 repeat (7R) allele of the dopamine receptor D4 gene has been associated with attention deficit hyperactivity disorder and risk taking. On the cross-population scale, 7R allele frequencies have been shown to be higher in populations with more of a history of long-term migrations. It has also been shown that the 7R allele is associated with individuals having multiple ancestries. Here, we conduct a replication of this latter finding with two independent samples. Measures of subjects' ancestry are used to examine past reproductive bonds. The individuals' history of interracial/ancestral dating and their feelings about this are also assessed. Tentative support for an association between multiple ancestries and the 7R allele was found. These results are dependent upon the method of questioning subjects about their ancestries, with only finer-scale measures of ancestry being associated with 7R. Interracial dating and feelings about interracial pairing were not related to the presence of the 7R allele. This study provides continued support for a role for the 7R allele in migration and/or mate choice patterns. However, replications and extensions of this study are needed and the way ancestry/race is assessed must be carefully considered.

Testosterone exposure, dopaminergic reward, and sensation-seeking in young men.

To test the relationship between androgen exposure, dopaminergic reward and sensation-seeking, we compared variation in salivary testosterone (T), 2D:4D digit ratio, facial masculinity, Zuckerman's sensation-seeking scale (SSS) and the D4 dopamine receptor (DRD4) genes from 98 young men, between the ages of 18 and 23 years. In univariate analyses, both salivary T and facial masculinity were significantly correlated with the SSS boredom susceptibility subscale, while the presence of the 7-repeat allele (7R+) in the dopamine receptor D4 gene was associated with the SSS thrill and adventure-seeking and overall sensation-seeking. Neither left nor right 2D:4D digit ratio was associated with any sensation-seeking scale. In multivariate models, salivary T and facial masculinity were significant predictors of SSS boredom susceptibility, while 7R+ was a significant predictor of SSS thrill and adventure-seeking. For overall SSS, both 7R+ and salivary T were significant predictors. There was no significant interaction of 7R+ and androgen exposure for SSS or any of the SSS subscales. These results add to earlier reports of an association between T and sensation-seeking. In addition, our results also indicate that genetic variation in DRD4 is independently associated with SSS sensation-seeking.

Origins of the Moken Sea Gypsies inferred from mitochondrial hypervariable region and whole genome sequences.

The origins of the Moken 'Sea Gypsies,' a group of traditionally boat-dwelling nomadic foragers, remain speculative despite previous examinations from linguistic, sociocultural and genetic perspectives. We explored Moken origin(s) and affinities by comparing whole mitochondrial genome and hypervariable segment I sequences from 12 Moken individuals, sampled from four islands of the Mergui Archipelago, to other mainland Asian, Island Southeast Asian (ISEA) and Oceanic populations. These analyses revealed a major (11/12) and a minor (1/12) haplotype in the population, indicating low mitochondrial diversity likely resulting from historically low population sizes, isolation and consequent genetic drift. Phylogenetic analyses revealed close relationships between the major lineage (MKN1) and ISEA, mainland Asian and aboriginal Malay populations, and of the minor lineage (MKN2) to populations from ISEA. MKN1 belongs to a recently defined subclade of the ancient yet localized M21 haplogroup. MKN2 is not closely related to any previously sampled lineages, but has been tentatively assigned to the basal M46 haplogroup that possibly originated among the original inhabitants of ISEA. Our analyses suggest that MKN1 originated within coastal mainland SEA and dispersed into ISEA and rapidly into the Mergui Archipelago within the past few thousand years as a result of climate change induced population pressure.