Admixture Rates Research Articles

Diversity of Fusarium species isolated from UK forage maize and the population structure of F. graminearum from maize and wheat.

Pre-harvest contamination of forage maize by mycotoxin producing Fusarium species was investigated in the UK in 2011 and 2012. A total of 15 Fusarium species were identified from a collection of 1,761 Fusarium isolates recovered from maize stalks and kernels. This study characterized the diversity of Fusarium species present in forage maize in the UK. The predominant species detected were F. graminearum (32.9%) and F. culmorum (34.1%). Along with those species; F. avenacem, F. cerealis, F. equiseti, F. langsethiae, F. napiforme, F. oxysporum, F. poae, F. proliferatum, F. scripi, F. solani, F. subglutinans, F. tricinctum and, F. verticillioides were occasionally isolated. The trichothecene genotypes for F. graminearum were determined to be 84.9% deoxynivalenol (DON) and 15.0% nivalenol (NIV) while F. culmorum isolates were determined to have 24.9% DON and 75.1% NIV genotypes. A Bayesian model-based clustering method with nine variable number of tandem repeat markers was used to evaluate the population genetic structure of 277 F. graminearum isolates from the maize and wheat in the UK. There were three genetic clusters detected which were DON in maize, NIV in maize and DON in wheat. There were high admixture probabilities for 14.1% of the isolates in the populations. In conclusion, increased maize production in the UK and the high admixture rates in a significant portion of F. graminearum populations in maize and wheat will contribute to a new pathogen population which will further complicate breeding strategies for tolerance or resistance to this pathogen in both crops.

Evolution of circoviruses in lorikeets lags behind its hosts

The presence of endogenous viral elements in host genomes hints towards much older host–virus relationships than predicted by exogenous phylogenies, with highly mutable single-stranded DNA (ssDNA) viruses and RNA viruses often occupying entangled multispecies ecological niches. The difficulty lies in unravelling the long-term evolutionary history of vertebrate virus–host relationships and determining the age of a potentially ancient tree based only fresh shoots at the tips. Resolving such lineages, and the sometimes great discrepancy amongst evolutionary timescales, is problematic, especially when purifying selection or recombination can significantly alter the accuracy of phylogenetic reconstruction methods. Pathogens which occupy entangled multispecies ecological niches add a further layer of complexity but we show that multi-host scenarios may also provide opportunities to identify allopatric or sympatric paleobiological signals that can unlock longer term phylogenies. We identified host-based, cryptic, sympatric differentiation in beak and feather disease virus in the Psittaciformes tribe Loriini along with endogenous circovirus motifs in Kea (Nestor notabilis) and Gondwanan vicariance estimates to infer the evolutionary timescale of the circoviruses. This demonstrated a chronology of psittacine circovirus speciation aligned to conservative Zealandic divergences for relic circovirus motifs in Kea and a 10million year divergence coinciding with the Papuan central range orogeny that triggered the radiation of Loriini and segregation of an antecedent viral clade in Australian lorikeets. Estimates of circovirus speciation in birds highlighted a Gondwanan dominant group in Neoaves with passerine, columbid and larid circoviruses deeply separated from those in waterfowl, consistent with a Triassic divergence of Galloanserae. The circovirus tree had a deep ancestry in invertebrates with a Palaeozoic expansion in fish and mammals. We show that longer term evolutionary relationships in viruses which have a high rate of mutation and admixture can be disentangled, highlighting that contemporary virus host-switching can be explained by deep intra-lineage host phylogeny.

Diverse rates of gene flow and long-distance migration in two moose Alces alces subpopulations in Europe

We assessed migration rates and gene flow amongst 16 local demes and six larger groups of moose identified by a previous microsatellite study across the entire European range of the species. The most important barrier to gene flow, the Baltic Sea along with the mountainous region in northern Fennoscandia, separates two genetically distinct moose subpopulations—the Scandinavian and the continental subpopulations—that originate from different glacial refugia. Our results showed that moose effectively migrated over long distances, but statistically significant gene flow was shorter in the Scandinavian (300–400 km) compared to the continental subpopulation (400–500 km). The admixture rates in local demes were markedly lower in the Scandinavian, than in the continental part of the moose range. Weaker gene flow amongst local demes in Scandinavia resulted from the major barrier of the Scandinavian Mountains. In the generally panmixed continental subpopulation of moose, two demes—one in NE Poland and another in the Kirov Oblast, Russia showed slightly hampered gene exchange with neighbouring demes, whereas one deme, in Arkhangelsk region, NE part of European Russia, appeared to have very high gene flow into other demes. Different evolutionary and demographic histories, population densities and land topography (large rivers) could have contributed to the low level barriers to gene flow in the continental subpopulation of moose.

Abstract B08: Highlighting the maturation of the MSI/NCI P20 South Carolina Cancer Disparities Research Center Partnership

Abstract The South Carolina Cancer Disparities Research Center (SC CaDRe), funded by the NIH/NCI Center to Reduce Cancer Health Disparities (CRCHD) in 2011, is a formal collaboration between the Medical University of South Carolina (MUSC) and South Carolina State University (SCSU, an historically black university). The SC CaDRe focuses on biological mechanisms of disparity in hormone-related cancers (breast and prostate cancer). The Sea Island population plays a prominent role in the three SC CaDRe research projects. The Sea Islanders are an African American ethnic group indigenous to the coastal southeast, with low rates of European American genetic admixture; as such they are ideal for inclusion in biomedical research. Each SC CaDRe research project includes Multiple PIs from MUSC and SCSU. The first research project is titled Biological Implications of DNA Glycation in Prostate Cancer Disparities; the second is titled MicroRNA Mediated Negative Regulation of Caveolin 1 as a Biological Mechanism Driving Breast Cancer Disparities; and the third is titled Feasibility Study of Breast Cancer Candidate Genes in Three Population Groups in South Carolina. The design and results of each project will be presented. The P20 SC CaDRe has led to two funded NIH R21 grants, an R01 grant, an R25E grant, and a DOD research training grant. Three undergraduate students from SCSU and four graduate students from MUSC have participated in SC CaDRe cancer research training, resulting in peer-reviewed publications and presentations at national scientific meetings. As a next step, the SC CaDRe investigators plan to submit an NIH/NCI CRCHD U54 grant application in 2016. Citation Format: Marvella E. Ford, Dennis K. Watson, James Stukes, Mahtabuddin Ahmed, David P. Turner, Ashley Evans Knowell, Victoria J. Findlay, Anita L. Harrison, Kendrea D. Knight, Heidi Varner, Kimberly Cannady, Judith D. Salley. Highlighting the maturation of the MSI/NCI P20 South Carolina Cancer Disparities Research Center Partnership. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr B08.

An optimized group mating design and determination of the admixture rate in Nile tilapia families

The Nile tilapia is the most productive and internationally traded food fish in the world. Many Nile tilapia families are needed to develop breeding programs for this species. The aim of this study was to develop Nile tilapia families using the Oreochromis species unique breeding characteristics (male territory establisher and female mouth brooders) and determine the mixing rate within each family. Both male and female fish were cultured in one pond in the reproductive season and the female mouths were checked every 5–8 days. When embryos were present, they were removed and cultivated independently as a family. As a result, 45 families were developed from the 60 female fish sampled. The embryo survival rate in aerated water varied from 85.5 to 100.0%. Seven polymorphic microsatellite loci were selected from a set of 31 for paternity identification. The CPE (combined paternity exclusion probability) of two microsatellite loci was higher than 0.93 and the CPE for the seven loci used in this study was as high as 0.9999. There were no unrelated individuals in five of the seven families analyzed and only one mixed individual in F29 and F30. The overall admixture rate was very low (2.2%). In this study, we developed an optimized group mating system. Furthermore, we verified that for group mating systems there were no mixed individuals in most families and the admixture rate of some families was very low according to the paternity analysis.

Postcopulatory sexual selection favors fertilization success of restocking hybrid quails over native Common quails (Coturnix coturnix)

Postcopulatory sexual selection plays an important role in the reproductive success of males in many species. Differences in fertilization success could affect rates of admixture and genetic introgression between divergent lineages. We investigated sperm precedence in matings in captivity involving Common quails (Coturnix coturnix) and farm quails of hybrid origin (C. coturnix × domestic Japanese quail, C. japonica), the last used in restocking practices to increase hunting bags. These inter-specific matings in natural conditions are claimed to represent an important threat to the conservation of native Common quail populations. Results showed that fertilization success of each male depended on (1) the time it spent with the female, (2) the presence of sperm from a previous male in the female oviduct, (3) the time that the previous partner had been copulating with the female, and, most importantly, (4) the genetic origin of the male (wild or farm). Farm hybrid males showed higher fertilization success than wild Common males, and they required less time with the female to fertilize the same proportion of eggs. The presence of sperm from another male in the female oviduct reduced the percentage of fertilized eggs by a male. However, this reduction was higher for wild males when the precedent mate was a farm male. In summary, the sperm of farm hybrid males may outcompete the sperm of native males and this could be favoring the introgression of domestic Japanese alleles into the Common quail population, thus constituting a severe conservation threat to wild Common quail populations.

Genetic variation and racial admixture in the Miskito of the southern Mosquito Shore, Nicaragua

Se estudió la variación electroforétíca de II loei que codifican para enzimas eritrocítícas, globinas y proteínas séricas en una muestra de 59 indígenas misquitos originarios de la región sur de la Mosquitia de Nicaragua. Siete loci, ALB, 03-, f-y o-globinas, LDHA, LDHB y TPI fueron monomórficos, mientras que API, CP, HP y TF fueron polimórficos. Esto se traduce en una proporción de,..loci polimórficos (P) de 0.364 y una heterocigosis media (H) de 0.077. Ambos valores se encuentran dentro del ámbito de variación mostrado por diez grupos indígenas de estirpe chibchense de Costa Rica y Panamá evaluados para los mismos loei [(P) = 0.364-182, (H) = 0.104-0.052). El análisis permitió una estimación de los porcentages mínimo (m) = 0.0), medio (mm = 7.34) y máximo (m, = 21.9) de mezcla racial con negros. A manera de comparación, esta mezcla se calculó también a partir de los resultados de A. Matson y su grupo, quienes estudiaron, en 1960, la variación genética, usando primordialmente grupos sanguíneos, en una muestra de misquitos de la región fronteriza entre Nicaragua y Honduras. Los resultados (m) = 6.05), (mm = I 1.0) Y (m, = 18.1) no fueron diferentes estadístícrunente, para los valores medios, bajo la suposición de que los alelos no-indígenas siguen la distribución de Poisson (P=0.42). Además, la disponibilidad de una fecha en la que se supone se inició la mezcla de los mísquitos con negros, en 1641, permitió el cálculo de la tasa de mezcla por generación. Dada una duración generacional de 27 años, su valor máximo se encuentra entre el 1.68 y el 1.91 %. Estos resultados indican que el acervo genético de los mísquitos aun conserva características propias de los grupos amerindios.

Abstract P1-09-20: Evaluating alcohol and tobacco use in an ethnically diverse sample of breast cancer patients: Implications for survivorship

Abstract Background/Objective: Data suggest that modifiable risk factors such as alcohol and tobacco use may increase the risk of breast cancer (BC) recurrence and reduce survival. According to 2012 data from the Centers for Disease Control (CDC) and Prevention Behavioral Risk Factor Surveillance System (BRFSS), 4.8% of women in South Carolina (SC) are heavy drinkers (>1 drink/day) with 9.6% having ≥4 drinks at least once in the past month (US state medians are 5.2% and 11.4%); 19.1% are current smokers (US state median 17.4%). Female BC mortality in SC is almost 50% higher in African Americans (AAs) than in European Americans (EAs; 27.5/100,000 and 19.1%, respectively). In SC, there is an AA subpopulation, the Sea Islanders, who carry the lowest AA rate of European genetic admixture. Given the substantial racial survival disparity we examined the patterns of alcohol and tobacco use in an on-going, ethnically diverse statewide study of women with recently diagnosed breast cancer. Methods: Participants were identified within 18 months post-diagnosis through the SC Central Cancer Registry (SCCCR). Women who opted into the study were interviewed via telephone, self-reporting data including race/ethnicity, educational status, alcohol consumption and tobacco use during the past 30 days. Published CDC guidelines were used to categorize alcohol and tobacco use. Results: During the first 24 months of recruitment, 172 women ages 38 to 90 years have opted into our study; 139 were interviewed (43 EAs and 96 AAs) and results analyzed. AAs were slightly younger (p=0.066) and tended to have less education (statistically not significant: p=0.114) Alcohol: The minority of participants self-identified consuming alcohol (29.0%). Heavy use was infrequent: two (1.4%) reported consuming on average >1 drink/day,and six (4.4%) consumed ≥4 drinks on any day. Alcohol consumption was less prevalent among AAs than EAs (p=0.025). Among those who consumed alcohol, usage did not differ between AAs and EAs. Tobacco: Smoking (daily or occasional) was reported by 7.5% of participants (AA vs EA: p=1.00). Alcohol and/or Tobacco: Use of alcohol and/or tobacco was 1.7 times as prevalent among EAs compared to AAs (47.6% vs 28.7%; p=0.032). Conclusions: Compared to self-reported state data few participants reported heavy alcohol consumption or current tobacco use, particularly AAs, but 34.6% of participants do use alcohol or tobacco. While these findings suggest that alcohol and tobacco may not contribute to the racial disparities in breast cancer mortality observed in SC, it is nonetheless imperative to reduce these modifiable risk factors and improve breast cancer outcomes for all breast cancer survivors, regardless of race and ethnicity. Table 1 African American (AA) N=96European American (EA) N=43p-valueAge (years): mean (±st dev*)58.8 (±11.6)62.9 (±13.2)0.066Education: more than high school51 (53.1%)29 (67.4%)0.114Alcohol in past 30 daysYes (vs No)22 (23.2%)18 (41.9%)0.025Among those who drink:Heavy: average >1 drink/day1 (4.6%)1 (5.6%)1.000Current tobacco useYes (vs No)7 (7.6%)3 (7.1%)1.000Among smokers: Daily use:4 (57.1%)3 (100%)0.475Alcohol and/or Tobacco27 (28.7%)20 (47.6%)0.032Both Alcohol and Tobacco2 (2.2%)1 (2.4%)1.000*standard deviation Citation Format: Vivian J Bea, Joan E Cunningham, Dana R Burshell, Marvella E Ford. Evaluating alcohol and tobacco use in an ethnically diverse sample of breast cancer patients: Implications for survivorship [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-09-20.

Amerindian admixture estimation based on serological and molecular methods

Amerindian admixture is an important parameter to consider in epidemiological studies in American countries, to make a proper selection of cases and controls. To compare Amerindian admixture estimates obtained using ABO*A and ABO*O blood group alleles and ancestral identity markers (AIMs) in the mixed Chilean population. Amerindian admixture rates were determined in 720 Chilean volunteers residing in Arica and born in the 15 regions of the country, using ABO*O and ABO*A alleles and 40 AIMs selected from more than 500,000 single nucleotide polymorphisms (SNPs). Mean admixture estimates obtained using ABO*O and ABO*A alleles and AIMs were 35, 47% and 48% respectively. There was concordance in estimates, with the exception of the admixture based on ABO*O allele and AIMs. In Chile, Amerindian admixture estimates obtained using ABO*A could be used as an alternative to AIMs in justified cases provided the sample size is reasonably large.

팽창재를 사용한 고성능 습식 숏크리트의 초기팽창 특성

본 논문에서는 고성능 습식 숏크리트의 균열발생을 억제하기 위하여 팽창재를 사용하였으며, 동시에 내구성 증진을 위해 광물성 혼화재료인 실리카퓸, 플라이애시, 고로슬래그 미분말, 메타카올린을 사용하여 숏크리트의 특성을 평가하였다. 실험은 팽창재를 시멘트량 대비 0%, 3%, 7%, 11% 및 15%를 혼입한 5가지 변수로 설정하여 팽창재가 보통 포틀랜트시멘트 콘크리트에 미치는 영향을 분석하였다. 그리고 동일한 작업성을 기준으로 광물성 혼화재료의 적정 혼입량으로 알려진 실리카퓸 10%, 플라이애시 20%, 고로슬래그 미분말 40%, 메타카올린 10%를 각각 혼합하여 무혼입 기준변수를 포함한 광물성 혼화재료에 대한 5가지 변수를 설정하여 실험을 진행하였다. 이에 대한 결론은 다음과 같다. 팽창재가 혼입되지 않은 포졸란재료 혼합 숏크리트에서는 초기 10시간 이전에 모든 팽창이 이루어지고 이후에는 미세한 수축이 발생되는 것을 확인하였다. 따라서 팽창재의 사용으로 초기 팽창률을 높여서 수화반응으로 발생되는 수축을 억제하였고, 장기적으로는 건조수축을 감소시켜 균열 발생을 방지하는 효과가 있음을 알 수 있었다. 포졸란재료를 혼합한 숏크리트에서는 팽창재를 11% 혼입했을 경우, 팽창 후 수축하지 않고 팽창을 유지하는 것으로 확인되었으며, 초기거동을 고려하여 팽창재를 과다하게 사용하면 내구성에 악영향을 미치므로 7~11% 가량 첨가하는 것이 초기에 발생되는 수화열로 인한 미세 균열을 예방할 수 있을 것으로 판단된다. In this dissertation, expansion admixture was used to suppress the cracking of high performance wet shotcrete. At the same time, characteristics of shotcrete were evaluated to using the silica-fume, fly ash, blast-furnace slag. The effect of expansion admixture (0, 3, 7, 11 and 15%) on the high-performance shotcrete was analyzed. Also, the effect of silica fume(10%), fly ash(20%), blast furnace slag(40%), meta-kaolin(10%) were analyzed. The incorporation rate of the mineral admixture were selected based on the previous studies. The results are as follows: All expansion occurred before initial 10 hours in the shotcrete mixture with pozzolan material without expansion agent. The shotcrete mixture with 11% expansive admixture showed a reduction in shrinkage, and this would lead to prevention of crack in concrete due to a reduction in long term shrinkage. The optimal content of expansive additive would range between 7.0% and 11.0% when considering expansion and contraction and heat of hydration.

부순모래를 사용한 습식 숏크리트의 광물성 혼화재료 혼입에 따른 내구성 평가

The purpose of this dissertation was to investigate the effect of mineral admixtures, such as fly ash, blast furnace slag powder, meta kaolin and silica fume, on the basic properties and durability of crushed sand shotcrete, selecting a series of shotcrete mixtures with a variable admixture. Compressive strength increased as the content of mineral admixtures increased, specially it was the most effective when using meta kaolin both at sample specimen and core after shotcreting. Rapid chloride ion permeability test and sulfuric acid resistance test showed that both durability increased as the substitute rate of mineral admixture increased. In air void analysis with image analysis, the targeted the spacing factor and specific surface were not satisfied because air-entrained agent was not used.

Admixture Indicative Interval (AII): a new approach to assess trends in genetic admixture

The genetic admixture is a dynamic and diachronic process, taking place during a great number of generations. Consequently, a sole admixture rate does not represent such an event and several estimates could help to take into account its dynamics. We developed an Admixture Indicative Interval (AII) which gives a mathematical key to avoid this problem by integrating several admixture estimators and their respective accuracy into a single metric and provides a trend in genetic admixture. To illustrate AIIs interests in admixture studies, AII were calculated using seven estimators on two sets of simulated SNPs data generated under two different admixture scenarios and were then calculated from several published admixed population data: a Comorian population and several Puerto-Rican and Colombian populations for recent admixture events as well as European populations representing the Neolithic/Paleolithic admixture for an older event. Our method provides intervals taking properly the variability and accuracy of admixture estimates into account. The AII lays in the intuitive interval in all actual and simulated datasets and is not biased by divergent points by the mean of a double-weighting step. The great quantity of heterogeneous parental contributions is synthesized by a few AII, which turn out to be more manageable and meaningful than aplenty variable point estimates. This offers an improvement in admixture study, allowing a better understanding of migratory flows. Furthermore, it offers a better assessment of admixture than the arithmetic mean, and enhances comparisons between regions, samples, and between studies on same population.

Carotid intima–media thickness value distributions in The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

ObjectiveCarotid intima–media thickness (IMT) is a noninvasive measurement of early atherosclerosis. Most IMT studies have involved populations with low rates of racial blending. The aim of the present article is to describe IMT value distributions and analyze the influence of sex and race on IMT values in a large Brazilian sample, a setting with a high rate of racial admixture. MethodsThe Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) is a multicenter cohort of 15,105 adult (aged 35–74 years) civil servants in six Brazilian cities. Baseline assessment included IMT measurements in both common carotid arteries. Race was self-reported. We studied the association between sex and race with IMT values using multiple linear regression models. We conducted analyses in all and low-risk individuals, defined as those without classical cardiovascular risk factors. ResultsWe analyzed complete IMT data from 10,405 ELSA-Brasil participants. We present nomograms by age for all and low-risk individuals, stratified by sex and race. We found that men had significantly higher maximal IMT values compared with women (β = 0.058; P < 0.001). This association remained for low-risk individuals (β = 0.027; P = 0.001). In addition, Brown and White individuals had lower maximal IMT values compared with Black individuals for all (β = −0.034 and β = −0.054, respectively; P < 0.001) and low-risk individuals (β = −0.027; P = 0.013 and β = −0.035; P < 0.001, respectively). ConclusionWe found significantly higher IMT values in men. We found significantly higher IMT values in Black individuals than White and Brown individuals. These results persisted when analyses were restricted to low-risk individuals.

Gene geography of Chile: regional distribution of American, European and African genetic contributions

The geographical distribution of genes plays a key role in genetic epidemiology. The Chilean population has three major stem groups (Native American, European and African). To estimate the regional rate of American, European and African admixture of the Chilean population. Forty single nucleotide polymorphisms (SNP´s) which exhibit substantially different frequencies between Amerindian populations (ancestry-informative markers or AIM´s), were genotyped in a sample of 923 Chilean participants to estimate individual genetic ancestry. The American, European and African individual average admixture estimates for the 15 Chilean Regions were relatively homogeneous and not statistically different. However, higher American components were found in northern and southern Chile and higher European components were found in central Chile. A negative correlation between African admixture and latitude was observed. On the average, American and European genetic contributions were similar and significantly higher than the African contribution. Weighted mean American, European and African genetic contributions of 44.34% ± 3 9%, 51.85% ± 5.44% and 3.81% ± 0.45%, were estimated. Fifty two percent of subjects harbor African genes. Individuals with Aymara and Mapuche surnames have an American admixture of 58.64% and 68.33%, respectively. Half of the Chilean population harbors African genes. Participants with Aymara and Mapuche surnames had a higher American genetic contribution than the general Chilean population. These results confirm the usefulness of surnames as a first approximation to determine genetic ancestry.

SomatiCA: Identifying, Characterizing and Quantifying Somatic Copy Number Aberrations from Cancer Genome Sequencing Data

Whole genome sequencing of matched tumor-normal sample pairs is becoming routine in cancer research. However, analysis of somatic copy-number changes from sequencing data is still challenging because of insufficient sequencing coverage, unknown tumor sample purity and subclonal heterogeneity. Here we describe a computational framework, named SomatiCA, which explicitly accounts for tumor purity and subclonality in the analysis of somatic copy-number profiles. Taking read depths (RD) and lesser allele frequencies (LAF) as input, SomatiCA will output 1) admixture rate for each tumor sample, 2) somatic allelic copy-number for each genomic segment, 3) fraction of tumor cells with subclonal change in each somatic copy number aberration (SCNA), and 4) a list of substantial genomic aberration events including gain, loss and LOH. SomatiCA is available as a Bioconductor R package at http://www.bioconductor.org/packages/2.13/bioc/html/SomatiCA.html.

Nuclear microsatellite variation in Malagasy baobabs (Adansonia, Bombacoideae, Malvaceae) reveals past hybridization and introgression

Adansonia comprises nine species, six of which are endemic to Madagascar. Genetic relationships between the Malagasy species remain unresolved due to conflicting results between nuclear and plastid DNA variation. Morphologically intermediate individuals between distinct species have been identified, indicative of interspecific hybridization. In this paper, microsatellite data are used to identify potential cases of hybridization and to provide insights into the evolutionary history of the genus on Madagascar. Eleven microsatellites amplified with new primers developed for Adansonia rubrostipa were used to analyse 672 individuals collected at 27 sites for the six Malagasy species and morphologically intermediate individuals. Rates of individual admixture were examined using three Bayesian clustering programs, STRUCTURE, BAPS and NewHybrids, with no a priori species assignment. Population differentiation was coherent, with recognized species boundaries. In the four Malagasy species of section Longitubae, 8·0, 9·0 and 9·5 % of individuals with mixed genotypes were identified by BAPS, NewHybrids and STRUCTURE, respectively. At sites with sympatric populations of A. rubrostipa and A. za, NewHybrids indicated these individuals to be F2 and, predominantly, backcrosses with both parental species. In northern Madagascar, two populations of trees combining A. za and A. perrieri morphology and microsatellite alleles were identified in the current absence of the parental species. The clear genetic differentiation observed between the six species may reflect their adaptation to different assortments of climate regimes and habitats during the colonization of the island. Microsatellite variation reveals that hybridization probably occurred in secondary contact between species of section Longitubae. This type of hybridization may also have been involved in the differentiation of a local new stabilized entity showing specific microsatellite alleles and morphological characters, suggesting a potential role of hybridization in the recent history of diversification on Madagascar.

Evolution under changing climates: climatic niche stasis despite rapid evolution in a non-native plant.

A topic of great current interest is the capacity of populations to adapt genetically to rapidly changing climates, for example by evolving the timing of life-history events, but this is challenging to address experimentally. I use a plant invasion as a model system to tackle this question by combining molecular markers, a common garden experiment and climatic niche modelling. This approach reveals that non-native Lactuca serriola originates primarily from Europe, a climatic subset of its native range, with low rates of admixture from Asia. It has rapidly refilled its climatic niche in the new range, associated with the evolution of flowering phenology to produce clines along climate gradients that mirror those across the native range. Consequently, some non-native plants have evolved development times and grow under climates more extreme than those found in Europe, but not among populations from the native range as a whole. This suggests that many plant populations can adapt rapidly to changed climatic conditions that are already within the climatic niche space occupied by the species elsewhere in its range, but that evolution to conditions outside of this range is more difficult. These findings can also help to explain the prevalence of niche conservatism among non-native species.

Racial and Ethnic Health Disparities in Reproductive Medicine: An Evidence-Based Overview

Racial and ethnic health disparities in reproductive medicine exist across the life span and are costly and burdensome to our healthcare system. Reduction and ultimate elimination of health disparities is a priority of the National Institutes of Health who requires reporting of race and ethnicity for all clinical research it supports. Given the increasing rates of admixture in our population, the definition and subsequent genetic significance of self-reported race and ethnicity used in health disparity research is not straightforward. Some groups have advocated using self-reported ancestry or carefully selected single-nucleotide polymorphisms, also known as ancestry informative markers, to sort individuals into populations. Despite the limitations in our current definitions of race and ethnicity in research, there are several clear examples of health inequalities in reproductive medicine extending from puberty and infertility to obstetric outcomes. We acknowledge that socioeconomic status, education, insurance status, and overall access to care likely contribute to the differences, but these factors do not fully explain the disparities. Epigenetics may provide the biologic link between these environmental factors and the transgenerational disparities that are observed. We propose an integrated view of health disparities across the life span and generations focusing on the metabolic aspects of fetal programming and the effects of environmental exposures. Interventions aimed at improving nutrition and minimizing adverse environmental exposures may act synergistically to reverse the effects of these epigenetic marks and improve the outcome of our future generations.

Implementing an evolutionary framework for understanding genetic relationships of phenotypically defined insect biotypes in the invasive soybean aphid (Aphis glycines)

Adaptive evolution of pest insects in response to the introduction of resistant cultivars is well documented and commonly results in virulent (i.e., capable of feeding upon resistant cultivars) insect populations being labeled as distinct biotypes. Phenotypically defined, biotypes frequently remain evolutionarily indistinct, resulting in ineffective application of virulence control measures and shorter durability of resistant cultivars. Here, we utilize an evolutionary framework to discern the genetic relationship between biotypes of the soybean aphid (Aphis glycines, Matsumura). The soybean aphid is invasive in North America and is among the most destructive pests of commercial soybean on the continent. Attempts to breed host-plant-resistant soybean have been hampered by the emergence of virulent aphid biotypes that are unaffected by the plant's resistance mechanism(s). Comparative population genetic analysis of virulent and avirulent (i.e., unable to feed on resistant cultivars) biotypes found populations to be genetically indistinguishable across biotype and geographic distance, with high rates of interpopulation immigration and admixture. The lack of genetic distinction between biotypes coupled with elevated genotypic diversity within all populations suggested virulence has a nongenetic-based or includes a gene complex that is widely distributed throughout soybean aphid populations, which undergo regular dispersal and unimpeded sexual recombination.

Changes in the genetic structure of Atlantic salmon populations over four decades reveal substantial impacts of stocking and potential resiliency

While the stocking of captive-bred fish has been occurring for decades and has had substantial immediate genetic and evolutionary impacts on wild populations, its long-term consequences have only been weakly investigated. Here, we conducted a spatiotemporal analysis of 1428 Atlantic salmon sampled from 1965 to 2006 in 25 populations throughout France to investigate the influence of stocking on the neutral genetic structure in wild Atlantic salmon (Salmo salar) populations. On the basis of the analysis of 11 microsatellite loci, we found that the overall genetic structure among populations dramatically decreased over the period studied. Admixture rates among populations were highly variable, ranging from a nearly undetectable contribution from donor stocks to total replacement of the native gene pool, suggesting extremely variable impacts of stocking. Depending on population, admixture rates either increased, remained stable, or decreased in samples collected between 1998 and 2006 compared to samples from 1965 to 1987, suggesting either rising, long-lasting or short-term impacts of stocking. We discuss the potential mechanisms contributing to this variability, including the reduced fitness of stocked fish and persistence of wild locally adapted individuals.