Knowledge and perceptions of human trafficking among community-based and faith-based organization members in South Los Angeles.

The objectives of this study were (1) to assess the knowledge and perceptions of human trafficking (HT) among leaders and staff from 11 community-based organizations (CBOs) and faith-based organizations (FBOs) in South Los Angeles, and (2) to identify gaps in knowledge of HT and inform community organizations regarding possible best practices in health promotion for addressing this emerging public health problem. A self-administered survey was conducted during the period from 4 December 2015 to 28 January 2016. Descriptive statistics were generated and a logistic regression model was constructed using SAS 9.3. A total of 277 CBO and FBO leaders and staff completed the survey. Participants demonstrated high levels of knowledge of HT but their knowledge was not comprehensive, as gaps exist in recognizing the context in which HT usually takes place; understanding the local laws that govern this activity; and ways to follow related policies/procedures when the problem is suspected. A majority (a) believed there were not enough services in Los Angeles County to help survivors of HT, (b) could not recognize the signs of HT, and (c) did not know what steps to take if they suspected this criminal activity. A statistically significant association was found between education and participants' knowledge of HT, and with their beliefs and attitudes toward this violation of human rights. Study findings suggest that, generally, CBO/FBO leaders and staff in South Los Angeles have good knowledge about HT. However, notable gaps in knowledge and misperceptions remain, suggesting opportunities for Public Health to further educate and intervene.

Community-based Flu Outreach Clinics in South Los Angeles: Client Satisfaction and Experiences.

OBJECTIVE: This study sought to better understand and improve influenza vaccination in low-income populations regardless of their health insurance/immigration status. It assessed client satisfaction and experiences with services provided at community-based "flu outreach" clinics in South Los Angeles. The clinics represent a community-public agency partnership-a model of vaccine delivery that was relatively novel to the region. DESIGN AND SAMPLE: During 2011-2012, a self-administered questionnaire was distributed to clients of the local health department's 39 flu outreach clinics in South Los Angeles. MEASURES: The study utilized a 10-item satisfaction scale and survey questions that gauged client history and experiences with present and prior vaccinations. RESULTS: Of 4,497 adults who were eligible, 3,860 completed the survey (participation rate = 86%). More than 90% were satisfied with their experiences at the clinics. Younger adults were significantly more likely than adults aged 65+ to report not having been vaccinated in the previous year (p < .05). No statistical differences were observed by gender or race/ethnicity. CONCLUSIONS: High satisfaction with flu outreach services in South Los Angeles suggests that this model for vaccine delivery could lead to meaningful client experience of care. Local health departments could capitalize on this model to improve preventive services delivery for the underserved.

Associations between ambient air pollution and Hypertensive Disorders of Pregnancy.

BACKGROUND: Exposure to ambient air pollution is linked to adverse pregnancy outcomes. Previous reports examining the relationship between ambient air pollution and Hypertensive Disorders of Pregnancy have been inconsistent. OBJECTIVES: We evaluated the effects of ambient air pollution on the odds of Hypertensive Disorder of Pregnancy and whether these associations varied by body mass index (BMI). METHODS: We conducted a retrospective, case-control study among 298 predominantly Hispanic women (136 clinically confirmed cases) who attended the Los Angeles County+University of Southern California Women's and Children's Hospital during 1996-2008. Trimester-specific carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), and particulate matter with aerodynamic diameter <10 µm and <2.5 µm (PM10, PM2.5) exposure were estimated based on 24-hour exposure level at residential address. Logistic regression models were fitted to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for two standard deviation increase in exposure levels. RESULTS: Exposures to CO and PM2.5 in the 1st trimester were significantly associated with Hypertensive Disorders of Pregnancy, and these associations were modified by BMI. In non-obese women (BMI <30), 1st trimester exposures to PM2.5 and CO were significantly associated with increased odds of Hypertensive Disorder of Pregnancy (ORs per 2-standard deviation increase in PM2.5 (7 µg/m(3)) and CO (1 ppm) exposures were 9.10 [95% CI: 3.33-24.6] and 4.96 [95% CI: 1.85-13.31], respectively). Additionally, there was a significantly positive association between exposure to O3 in the 2nd trimester and Hypertensive Disorder of Pregnancy (OR per 15 ppb=2.05; 95% CI: 1.22-3.46). CONCLUSION: Among non-obese women, 1st trimester exposure to PM2.5 and carbon monoxide are associated with increased odds of Hypertensive Disorder of Pregnancy.

Contrasting signatures of population growth for mitochondrial DNA and Y chromosomes among human populations in Africa.

A history of Pleistocene population expansion has been inferred from the frequency spectrum of polymorphism in the mitochondrial DNA (mtDNA) of many human populations. Similar patterns are not typically observed for autosomal and X-linked loci. One explanation for this discrepancy is a recent population bottleneck, with different rates of recovery for haploid and autosomal loci as a result of their different effective population sizes. This hypothesis predicts that mitochondrial and Y chromosomal DNA will show a similar skew in the frequency spectrum in populations that have experienced a recent increase in effective population size. We test this hypothesis by resequencing 6.6 kb of noncoding Y chromosomal DNA and 780 basepairs of the mtDNA cytochrome c oxidase subunit III (COIII) gene in 172 males from 5 African populations. Four tests of population expansion are employed for each locus in each population: Fu's Fs statistic, the R(2) statistic, coalescent simulations, and the mismatch distribution. Consistent with previous results, patterns of mtDNA polymorphism better fit a model of constant population size for food-gathering populations and a model of population expansion for food-producing populations. In contrast, none of the tests reveal evidence of Y chromosome growth for either food-gatherers or food-producers. The distinct mtDNA and Y chromosome polymorphism patterns most likely reflect sex-biased demographic processes in the recent history of African populations. We hypothesize that males experienced smaller effective population sizes and/or lower rates of migration during the Bantu expansion, which occurred over the last 5,000 years.

From social to genetic structures in central Asia.

Pastoral and farmer populations, who have coexisted in Central Asia since the fourth millennium B.C., present not only different lifestyles and means of subsistence but also various types of social organization. Pastoral populations are organized into so-called descent groups (tribes, clans, and lineages) and practice exogamous marriages (a man chooses a bride in a different lineage or clan). In Central Asia, these descent groups are patrilineal: The children are systematically affiliated with the descent groups of the father. By contrast, farmer populations are organized into families (extended or nuclear) and often establish endogamous marriages with cousins. This study aims at better understanding the impact of these differences in lifestyle and social organization on the shaping of genetic diversity. We show that pastoral populations exhibit a substantial loss of Y chromosome diversity in comparison to farmers but that no such a difference is observed at the mitochondrial-DNA level. Our analyses indicate that the dynamics of patrilineal descent groups, which implies different male and female sociodemographic histories, is responsible for these sexually-asymmetric genetic patterns. This molecular signature of the pastoral social organization disappears over a few centuries only after conversion to an agricultural way of life.

Deep haplotype divergence and long-range linkage disequilibrium at xp21.1 provide evidence that humans descend from a structured ancestral population.

Fossil evidence links human ancestry with populations that evolved from modern gracile morphology in Africa 130,000-160,000 years ago. Yet fossils alone do not provide clear answers to the question of whether the ancestors of all modern Homo sapiens comprised a single African population or an amalgamation of distinct archaic populations. DNA sequence data have consistently supported a single-origin model in which anatomically modern Africans expanded and completely replaced all other archaic hominin populations. Aided by a novel experimental design, we present the first genetic evidence that statistically rejects the null hypothesis that our species descends from a single, historically panmictic population. In a global sample of 42 X chromosomes, two African individuals carry a lineage of noncoding 17.5-kb sequence that has survived for >1 million years without any clear traces of ongoing recombination with other lineages at this locus. These patterns of deep haplotype divergence and long-range linkage disequilibrium are best explained by a prolonged period of ancestral population subdivision followed by relatively recent interbreeding. This inference supports human evolution models that incorporate admixture between divergent African branches of the genus Homo.

Evidence for archaic Asian ancestry on the human X chromosome.

The human RRM2P4 pseudogene has a pattern of nucleotide polymorphism that is unlike any locus published to date. A gene tree constructed from a 2.4-kb fragment of the RRM2P4 locus sequenced in a sample of 41 worldwide humans clearly roots in East Asia and has a most-recent common ancestor approximately 2 Myr before present. The presence of this basal lineage exclusively in Asia results in higher nucleotide diversity among non-Africans than among Africans. A global survey of a single-nucleotide polymorphism that is diagnostic for the basal, Asian lineage in 570 individuals shows that it occurs at frequencies up to 53% in south China, whereas only one of 177 surveyed Africans carries this archaic lineage. We suggest that this ancient lineage is a remnant of introgressive hybridization between expanding anatomically modern humans emerging from Africa and archaic populations in Eurasia.

Global patterns of human mitochondrial DNA and Y-chromosome structure are not influenced by higher migration rates of females versus males.

Global-scale patterns of human population structure may be influenced by the rate of migration among populations that is nearly eight times higher for females than for males. This difference is attributed mainly to the widespread practice of patrilocality, in which women move into their mates' residences after marriage. Here we directly test this hypothesis by comparing global patterns of DNA sequence variation on the Y chromosome and mitochondrial DNA (mtDNA) in the same panel of 389 individuals from ten populations (four from Africa and two each from Europe, Asia and Oceania). We introduce a new strategy to assay Y-chromosome variation that identifies a high density of single-nucleotide polymorphisms, allows complete sequencing of all individuals rather than relying on predetermined markers and provides direct sequence comparisons with mtDNA. We found the overall proportion of between-group variation (Phi(ST)) to be 0.334 for the Y chromosome and 0.382 for mtDNA. Genetic differentiation between populations was similar for the Y chromosome and mtDNA at all geographic scales that we tested. Although patrilocality may be important at the local scale, patterns of genetic structure on the continental and global scales are not shaped by the higher rate of migration among females than among males.

Heterogeneous patterns of variation among multiple human x-linked Loci: the possible role of diversity-reducing selection in non-africans.

Studies of human DNA sequence polymorphism reveal a range of diversity patterns throughout the genome. This variation among loci may be due to natural selection, demographic influences, and/or different sampling strategies. Here we build on a continuing study of noncoding regions on the X chromosome in a panel of 41 globally sampled humans representing African and non-African populations by examining patterns of DNA sequence variation at four loci (APXL, AMELX, TNFSF5, and RRM2P4) and comparing these patterns with those previously reported at six loci in the same panel of 41 individuals. We also include comparisons with patterns of noncoding variation seen at five additional X-linked loci that were sequenced in similar global panels. We find that, while almost all loci show a reduction in non-African diversity, the magnitude of the reduction varies substantially across loci. The large observed variance in non-African levels of diversity results in the rejection of a neutral model of molecular evolution with a multi-locus HKA test under both a constant size and a bottleneck model. In non-Africans, some loci harbor an excess of rare mutations over neutral equilibrium predictions, while other loci show no such deviation in the distribution of mutation frequencies. We also observe a positive relationship between recombination rate and frequency spectra in our non-African, but not in our African, sample. These results indicate that a simple out-of-Africa bottleneck model is not sufficient to explain the observed patterns of sequence variation and that diversity-reducing selection acting at a subset of loci and/or a more complex neutral model must be invoked.

Genetic evidence for unequal effective population sizes of human females and males.

The time to the most recent common ancestor (TMRCA) of the human mitochondria (mtDNA) is estimated to be older than that of the nonrecombining portion of the Y chromosome (NRY). Surveys of variation in globally distributed humans typically result in mtDNA TMRCA values just under 200 thousand years ago (kya), whereas those for the NRY range between 46 and 110 kya. A favored hypothesis for this finding is that natural selection has acted on the NRY, leading to a recent selective sweep. An alternate hypothesis is that sex-biased demographic processes are responsible. Here, we re-examine the disparity between NRY and mtDNA TMRCAs using data collected from individual human populations--a sampling strategy that minimizes the confounding influence of population subdivision in global data sets. We survey variation at 782 bp of the mitochondrial cytochrome c oxidase subunit 3 gene as well as at 26.5 kb of noncoding DNA from the NRY in a sample of 25 Khoisan, 24 Mongolians, and 24 Papua New Guineans. Data from both loci in all populations are best described by a model of constant population size, with the exception of Mongolian mtDNA, which appears to be experiencing rapid population growth. Taking these demographic models into account, we estimate the TMRCAs for each locus in each population. A pattern that is remarkably consistent across all three populations is an approximately twofold deeper coalescence for mtDNA than for the NRY. The oldest TMRCAs are observed for the Khoisan (73.6 kya for the NRY and 176.5 kya for mtDNA), whereas those in the non-African populations are consistently lower (averaging 47.7 kya for the NRY and 92.8 kya for mtDNA). Our data do not suggest that differential natural selection is the cause of this difference in TMRCAs. Rather, these results are most consistent with a higher female effective population size.

Nucleotide variation at Msn and Alas2, two genes flanking the centromere of the X chromosome in humans.

The centromeric region of the X chromosome in humans experiences low rates of recombination over a considerable physical distance. In such a region, the effects of selection may extend to linked sites that are far away. To investigate the effects of this recombinational environment on patterns of nucleotide variability, we sequenced 4581 bp at Msn and 4697 bp at Alas2, two genes situated on either side of the X chromosome centromere, in a worldwide sample of 41 men, as well as in one common chimpanzee and one orangutan. To investigate patterns of linkage disequilibrium (LD) across the centromere, we also genotyped several informative sites from each gene in 120 men from sub-Saharan Africa. By studying X-linked loci in males, we were able to recover haplotypes and study long-range patterns of LD directly. Overall patterns of variability were remarkably similar at these two loci. Both loci exhibited (i) very low levels of nucleotide diversity (among the lowest seen in the human genome); (ii) a strong skew in the distribution of allele frequencies, with an excess of both very-low and very-high-frequency derived alleles in non-African populations; (iii) much less variation in the non-African than in the African samples; (iv) very high levels of population differentiation; and (v) complete LD among all sites within loci. We also observed significant LD between Msn and Alas2 in Africa, despite the fact that they are separated by approximately 10 Mb. These observations are difficult to reconcile with a simple demographic model but may be consistent with positive and/or purifying selection acting on loci within this large region of low recombination.

Contrasting patterns of Y chromosome variation in Ashkenazi Jewish and host non-Jewish European populations.

The molecular basis of more than 25 genetic diseases has been described in Ashkenazi Jewish populations. Most of these diseases are characterized by one or two major founder mutations that are present in the Ashkenazi population at elevated frequencies. One explanation for this preponderance of recessive diseases is accentuated genetic drift resulting from a series of dispersals to and within Europe, endogamy, and/or recent rapid population growth. However, a clear picture of the manner in which neutral genetic variation has been affected by such a demographic history has not yet emerged. We have examined a set of 32 binary markers (single nucleotide polymorphisms; SNPs) and 10 microsatellites on the non-recombining portion of the Y chromosome (NRY) to investigate the ways in which patterns of variation differ between Ashkenazi Jewish and their non-Jewish host populations in Europe. This set of SNPs defines a total of 20 NRY haplogroups in these populations, at least four of which are likely to have been part of the ancestral Ashkenazi gene pool in the Near East, and at least three of which may have introgressed to some degree into Ashkenazi populations after their dispersal to Europe. It is striking that whereas Ashkenazi populations are genetically more diverse at both the SNP and STR level compared with their European non-Jewish counterparts, they have greatly reduced within-haplogroup STR variability, especially in those founder haplogroups that migrated from the Near East. This contrasting pattern of diversity in Ashkenazi populations is evidence for a reduction in male effective population size, possibly resulting from a series of founder events and high rates of endogamy within Europe. This reduced effective population size may explain the high incidence of founder disease mutations despite overall high levels of NRY diversity.