Homogeneous Population Research Articles

Otolith chemistry suggests population heterogeneity within a genetically homogeneous Indian scad population along Indian coast

The Indian scad, Decapterus russelli is one of the most exploited pelagic resources of India. Population genetic analyses using mitochondrial and nuclear markers indicated a lack of genetic structuring among populations from Indian waters. As this species is highly migratory, it is also important to establish the environmental influence on its population structure. In the present study, the whole sagittal otolith composition was analysed using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to assess spatial distribution of D. russelli collected from 4 sites along the Indian coast. Elemental ratios (Ba/Ca, Fe/Ca, K/Ca, Mg/Ca, Na/Ca, Sr/Ca and Zn/Ca) were analysed using univariate and multivariate statistics to determine whether this chemical signature can provide insight into the adaptive patterns. All element/Ca ratios are found to be significantly different between the four sampling locations (ANOVA, p < 0.05; MANOVA, p < 0.05). Five of the element/Ca ratios were found to be significantly different when the data was analysed coastwise (ANOVA, p < 0.05; MANOVA, p < 0.05). The LDA plot also showed the spatial heterogeneity of Element/Ca ratios between the four sampling sites, but some overlaps were also observed, reflecting the migratory ability of the species. This basic information on spatial ecology is required for formulating effective management and conservation strategies for the species.

Passaging Human Tauopathy Patient Samples in Cells Generates Heterogeneous Fibrils with a Subpopulation Adopting Disease Folds.

The discovery by cryo-electron microscopy (cryo-EM) that the neu-ropathological hallmarks of different tauopathies, including Alzheimer's disease, corticobasal degeneration (CBD), and progressive supranuclear palsy (PSP), are caused by unique misfolded conformations of the protein tau is among the most profound developments in neurodegenerative disease research. To capitalize on these discoveries for therapeutic development, one must achieve in vitro replication of tau fibrils that adopt the representative tauopathy disease folds, which represents a grand challenge for the field. A widely used approach has been seeded propagation using pathological tau fibrils derived from post-mortem patient samples in biosensor cells that expresses a fragment of the tau protein known as K18, or Tau4RD, containing the microtubule-binding repeat domain of tau as the substrate. The new insights from cryo-EM raised the question of whether the Tau4RD fragment is capable of adopting characteristic tau folds found in CBD and PSP patient fibrils, and whether cell-passaged and amplified tau fibrils can be used as seeds to achieve cell-free assembly of recombinant 4R tau into fibrils without the addition of cofactors. Using Double Electron Electron Resonance (DEER) spectroscopy, we discovered that cell-passaged pathological seeds generate heterogeneous fibrils that are, however, distinct between the CBD and PSP lysate-seeded fibrils, and vastly different from heparin-induced tau fibril structures. Moreover, the lysate-seeded fibrils contain a characteristic sub-population that resembles the disease fold corresponding to the respective starting patient sample. These findings indicate that templated propagation using CBD and PSP patient-derived fibrils is possible with a tau fragment that does not contain the entire pathological fibril core, but also that additional mechanisms must be tuned to converge on a homogeneous fibril population.

The role of personality traits and life stress in alcohol use disorder: Insights from NGF gene polymorphisms of Han Chinese population in Taiwan.

Alcohol use disorder (AUD) is a complex neuropsychiatric condition influenced by genetic and environmental factors. Nerve growth factor (NGF) plays a crucial role in neuronal neuroplasticity and chronic alcohol consumption may alter NGF levels in specific brain regions. The study investigates the associations between NGF gene polymorphisms, susceptibility to AUD, and specific stress and personality characteristics. Our study involved 1133 participants from a homogeneous Han Chinese population, 587 of whom had AUD and 546 were controls. To minimize potential confounding factors, the AUD group was stratified by sex and age at baseline. A total of 414 participants completed the Life Event Questionnaires (LEQ), while 559 participants completed the Tridimensional Personality Questionnaire (TPQ). The NGF's rs7523654 and rs11102929 loci were significantly associated with AUD, especially in female subgroups. Additional haplotype research confirmed similar findings. AUD patients showed more vital propensities for novelty seeking (NS) and harm avoidance (HA) compared to controls. Additionally, they recorded higher negative LEQ results. Notably, HA and negative LEQ scores among AUD people were significantly affected by the SNP rs11102929 in the NGF gene. The age at which AUD first manifested and NS scores showed a reverse link, suggesting that a higher NS characteristic may predispose people to develop AUD earlier in life. The findings suggest that the NGF gene may influence AUD susceptibility and its links to personality traits and life stress. However, the small sample of women with AUD limits the reliability of these associations, highlighting the need for further study.

Barriers and facilitators to conducting human subjects research at a safety net institution from the perspective of researchers.

The COVID-19 pandemic revealed glaring problems with clinical research enterprise. Faced with crisis, several trials opened rapidly but enrolled homogenous populations with few Black, Indigenous, and People of Color (BIPOC) individuals. Inclusive trial enrollment is important to inspire trust and confidence in BIPOC populations that have been historically excluded or harmed from research and to improve the generalizability of research findings. Safety-net hospitals and institutions often care for BIPOC populations, and thus it is essential to improve equitable participation in research at these institutions. In this study, we sought to understand barriers and facilitators to research participation at safety net institutions. We conducted semi-structured interviews among principal investigators, research assistants, research coordinators, and research nurses who conducted human subjects research at an urban, safety-net hospital from October, 2022 to December, 2022. We used inductive qualitative methods to identify themes associated with barriers and facilitators to clinical research participation. We completed 28 interviews and identified five themes: (1) compared to non-safety net systems, safety-net systems were perceived to require additional resources and funding to achieve comparable research recruitment and retention; (2) language barriers and translational processes are burdensome for researchers; (3) interactions between research staff and patients impact trust; (4) social determinants of health specific to safety-net populations are a barrier to participation; (5) competing priorities between clinical staff and researchers exist. Safety net institutions face several barriers to conducting human subjects research. However, identified facilitators may help inform future efforts to reduce inequities in research participation.

Population structure analysis and molecular characterization of duckweed genotypes using ipbs and issr markers

The duckweed subfamily, Lemnoideae, is the smallest group of flowering plants. It is considered a vegetable since duckweeds are used for human nutrition, and there are species in this plant group with high potential for minor vegetables. Genetic diversity and molecular characterization of duckweed genotypes grown in different ecosystems were determined in this study. Using ISSR (Inter Simple Sequence Repeats) and iPBS (Inter-Primer Binding Site) markers, 67 genotypes of five duckweed species were characterized. ISSR and iPBS methods identified 100% polymorphism, with genetic similarity coefficients between Spirodela and Lemna species ranging from 0.17 to 0.56. Structure analysis conducted according to K=6 calculation revealed that L. minor species had the most homogeneous and diverse populations. Duckweed genotypes and species displayed a wide range of genetic diversity. Using various marker techniques, we determined the genetic structure of duckweed and characterized it as an alternative cheap, sustainable, and cheap source of protein, vegetables, and biofuel. As a result of this study, data obtained from duckweed genotypes will be useful for understanding molecular mechanisms in future genetic improvements of duckweed species. Bangladesh J. Bot. 53(4): 871-880, 2024 (December)

Comparison of Students' Mathematical Communication Ability Between Think Pair Share and Numbered Head Together Cooperative Learning Model

&lt;em&gt;This study aimed to find out the comparison between students' mathematical communication ability taught by Think Pair Share and Numbered Head Together cooperative learning model. The population in the study were all students in grade X MAN 2 Model Medan. The sample were all students of class X-C with 37 students as experimental class I and class X-H with 36 students as experimental class II, which were selected through random sampling technique. The experimental class I was taught by Think Pair Share cooperative learning model while the experimental class II with Numbered Head Together cooperative learning model. This research was quasi experimental with posttest only control group design. Data collection instrument used was mathematics communication ability test that have been tested for validity and reliability. Before testing the hypothesis, normality test was carried out using Shapiro-Wilk test and homogeinity test using Levene test on the research data. The results showed that the samples came from normal and homogeneous distributed population. Hypothesis testing with t-test show that t_count&amp;gt;t_table(2,4 &amp;gt; 1,666). Thus H_0 is rejected and H_1 is accepted, so students’ mathematical communication ability taught by Think Pair Share cooperative learning model is better than the students’ mathematical communication ability taught by Numbered Head Together cooperative learning model.&lt;/em&gt;

Response of the gut microbiome and metabolome to dietary fiber in healthy dogs.

Consumption of dietary fiber changes the composition of the gut microbiome and, to a larger extent, the associated metabolites. Production of health-relevant metabolites such as short-chain fatty acids from fiber depends both on the consumption of a specific fiber and on the enrichment of beneficial metabolite-producing species in response to it. Even in a seemingly homogeneous population, the benefit received from fiber consumption is personalized and emphasizes specific fiber-microbe-host interactions. These observations are relevant for both population-wide and personalized nutrition applications.

The Health Economics of Life Expectancy

For a life office, the potential deviations from the mortality assumptions applied in premium setting at the time of incepting contracts represents serious threats to its financial performance when underwriting life insurance policies including annuities. Furthermore, in view of the uncertainties associated with the complete expectation of life evolving from the inadequately modelled life expectancy as a form of mortality risk indicator, this study explores the CMI’s generalized Makeham’s mortality law which would be advantageous to compute complete life expectancies. When continuous parsimonious parametric mortality intensities are Makehamized, then the limiting value of the continuous whole life annuity function is construed to mean the complete life expectancy which is expressed in line with special functions such as incomplete upper gamma function for a homogeneous insured population. In this study, the objective are to (i) construct actuarial estimation of individual’s time remaining through single life parameterization from GM(1,2) (ii) construct closed form expressions for complete life expectancy using the properties of the special functions as applicable in classical mortality dynamics. To circumvent the need for any rigorous numerical procedures, the advanced technique of the Gradshteyn and Ryzhik’s analytic integral is applied in computing the complete life expectancies. From our results, it is apparent that ex(male)&lt; ex(female). Specifically, within the interval 111&lt;x&lt;119 for women, there is a sharp decrease in complete life expectancies whereas for men within the interval 75&lt;x&lt;119, life expectancies sharply decrease confirming earlier exposure of men to mortality risk.

Development of a territory-wide household-based composite index for measuring relative distribution of households by economic status in individual small areas throughout Hong Kong

BackgroundMany countries have developed their country/nation-wide multidimensional area-based index on deprivation or socioeconomic status for resource allocation, service planning and research. However, whether each geographical unit proxied by a single index is sufficiently small to contain a relatively homogeneous population remains questionable. Globally, this is the first study that presents the distribution of domestic households by the territory-wide economic status index decile groups within each of the 2,252 small subunit groups (SSUGs) throughout Hong Kong, with a median study population of 1,300 and a median area of 42,400 m2.MethodsThe index development involved 248,000 anonymized sampled household-based data collected from the population census, representing 2·66 million domestic households and 6·93 million population in mid-2021. Our composite index comprises seven variables under income-/wealth-related and housing-related domains with weights determined using the analytic hierarchy process. After ranking all households from the most to the least well-off according to the numeric/ordinal value of each variable and then calculating their weighted rank scores, they were segregated into ten deciles from D1 (top 10% most well-off) to D10 (bottom 10%). Their relative distribution was summarized in a three-dimensional ternary plot to distinguish patterns across the 2,252 SSUGs within the 18 administrative districts.ResultsIn Hong Kong, of the 2,252 SSUGs, only one-quarter contain a homogeneous composition of households with similar economic status, while the other three-quarters are heterogeneous to varying extents. Of the 18 administrative districts, only two are concentrated with more homogeneously well-off SSUGs.ConclusionsSmall-sized geographical units may contain a heterogeneous composition of households with diverse economic statuses, underlying the need for more precise information to quantify their relative distribution. Results of this study are disseminated via an online interactive map dashboard (https://experience.arcgis.com/experience/‌b4c7643feb9043eb94b3add386c4b71c/) which can serve as a versatile planning tool capable of performing analysis at different varying geographic scales for community-based resource prioritization, service planning and research across different domains.

The Microbiome Landscape of Adenomyosis: A Systematic Review.

Alterations in the microbiome composition have been identified in common gynecologic pathologies such as endometriosis carving a new frontier in diagnosis and treatment. We aimed to examine the existing literature on perturbations in the reproductive tract microbiome of individuals with adenomyosis informing future therapeutic targets. To examine the association between the reproductive tract microbiome composition among individuals with adenomyosis when compared to controls that can lead to new research evaluating novel mechanisms of action and treatment modalities. A systematic literature search identified studies that compared differences in microbiome composition using culture-independent microbiome analysis between individuals with adenomyosis when compared to controls. Five observational cross-sectional studies characterizing the lower and upper reproductive tract in humans were included. The diagnostic criteria of adenomyosis included surgical and imaging-based criteria. All studies used a 16S rRNA sequencing method. All individuals were recruited from either China or Thailand. An association between adenomyosis and alterations in the microbiome composition included relative deficiencies in Lactobacillus and relative enrichment of anaerobic and gram-negative bacteria when compared to control participants. Comparative studies suggest that there are significant perturbations in the microbiota composition of individuals with adenomyosis when compared with controls. Limiting conclusions include relative small sample sizes, a homogeneous population, and scant clinical phenotypic data. This systematic review identified significant alterations in the bacterial composition of adenomyosis cases that can be leveraged to design mechanistic studies and future innovative approaches to diagnose and manage this pathology. Trial registration: PROSPERO (CRD42023494563). Registered December 28, 2023.

Challenges and Supports for Implementing Health Equity During National Accreditation Among Small Local Health Departments in the United States.

This article focuses on supports and challenges to health equity that small local health departments (LHDs) experienced while working toward national reaccreditation or Pathways Recognition with the Public Health Accreditation Board's Standards & Measures Version 2022 (PHAB S&M v2022). The study team conducted 22 qualitative interview sessions with members of health department leadership teams. In the spring of 2024, participants from 4 small LHDs in the western and midwestern regions of the United States participated in individual remote interview sessions. Participants were members of leadership teams in LHDs with population jurisdictions less than 50000. Common challenges relating to the health equity measures in the PHAB S&M v2022 included external influences on equity language; lack of small population data; and racially and ethnically homogeneous populations and staff. The main support was the national equity standards provided justification for pursuing equity work. Strategies to overcome challenges associated with the equity measures included staff training, seeking alternative equity language, and examining socioeconomic inequities in addition to race and ethnicity. Internal workforce understanding of health equity was improved through department-wide training initiatives. When working under restrictive language requirements for state agencies, grants, and other funding sources, staff suggested using alternative phrases and keywords such as level playing field and equal access. When addressing racially and ethnically homogenous populations, staff pursued equity in terms of income and focused on those living with pre-existing conditions (ie, diabetes). Ensuring that LHDs can work toward health equity is crucial for reducing health inequities. While the equity focus of PHAB S&M v2022 proved challenging, for this selection of LHDs, participants affirmed that PHAB accreditation allowed them to solidify their equity work to better serve their communities.

Increased BMI Velocity is Associated with Elevated Patient Health Questionnaire-9 Scores in Adolescents with Obesity.

Existing studies that have demonstrated a positive association between obesity and depression have been among adults, did not utilize the Patient Health Questionnaire (PHQ), or were conducted in a homogenous patient population. In this retrospective longitudinal cohort study of patients >11 and <18 years old with obesity in one health system we analyzed associations between change in BMI between two BMI measurements and PHQ-9 scores using chi-square and Kruskal-Wallis tests. We used PHQ-9 scores dichotomized at </≥5 as the outcome in logistic regression models to calculate the adjusted odds of having a higher PHQ-9 score for each increase in BMI per month. One-unit higher BMI change per month was associated with 2.52 times higher odds of PHQ-9 score over 5 (95% CI: 1.57-4.05) after adjusting for sex, baseline BMI, age, race, ethnicity, language, and insurance. BMI changes are associated with an increased risk of higher PHQ-9 scores. Close attention to depression screening in this population may be an important addition to other routine screening in pediatric patients with obesity.

Brief Assessment Tools for Obsessive Compulsive Disorders in Children: A Systematic Review.

Children and adolescents with suspected obsessive-compulsive disorder (OCD). To estimate the comparative performance of brief diagnostic assessment tools. PubMed, the Cochrane Register of Clinical Trials, the Cochrane Database of Systematic Reviews, Embase, CINAHL, PsycINFO, and ERIC, and for unpublished studies with reported results in ClinicalTrials.gov through May 15, 2024. Studies of children (up to age 21) with a clinical suspicion of OCD that evaluated the accuracy (predictive validity) of brief assessment tools for OCD, compared to a reference standard. We extracted participant characteristics, scale and reference standard information, results, and risk of bias assessment. We performed random-effects diagnostic meta-analysis where feasible. We assessed strength of evidence for each scale. There is moderate strength of evidence that the 8-question version of the Child Behavior Checklist-Obsessive Compulsive subscale is sufficiently sensitive and specific (summary area under the curve of 0.84, 95% CI 0.74 to 0.91) to prompt specialist referral for additional diagnostic assessment. Other tools may perform as well or better, but the current evidence is insufficient to justify broad conclusions about their performance. Few studies per scale, case-control studies, and homogenous White populations may preclude generalizability of tool performance. Based on the current evidence the CBCL-OCS probably is sufficiently accurate to indicate which youth should be further evaluated for OCD, but further research is needed to establish that the 8-question subscale can function as a stand-alone measure. The available evidence is insufficient for other brief assessment tools.

Lumbar Spinal Fusion Outcomes in Patients With Cancer Compared to Matched Peers Without Cancer.

Retrospective Matched Cohort Study. Optimization of medical comorbidities is an essential part of preoperative management. However, the isolated effects of individual comorbidities have not been evaluated within a homogenous spine surgery population. This exact matching study aims to assess the independent effects of cancer on outcomes following single-level lumbar fusions for non-cancer surgery. 4680 consecutive patients undergoing single-level posterior-only lumbar fusion were retrospectively enrolled. Univariate statistics and coarsened exact matching (CEM) were computed to evaluate outcomes between cancer patients and those without comorbidities. By logistic regression, malignancy conferred a higher risk of surgical complication (P = 0.016, OR = 2.64, CI = [1.200,5.790]), 30- and 90- day readmission (P = 0.012, OR = 2.025, CI = [1.170-3.510]; P < 0.001, OR = 2.34, CI = [1.430, 3.830], respectively), 90-day reoperation (P < 0.001, OR = 2.16, [1.110, 4.200]), and death at 90-days (P = 0.032, OR = 8.27, CI = [1.200, 56.850]). After matching, malignancy was associated with increased odds of incidental durotomy (6 vs 0 cases, P = 0.048) and death at both 30 and 90 days (both: OR = 8.0, P = 0.020, CI = [1.00, 63.960]). No cases of durotomy occurred in cases with mortality in the matched sample, suggesting independent relationships. There were no differences in length of stay, non-home discharge, ED evaluation, readmission, or reoperations. Among otherwise exact-matched patients undergoing single level lumbar fusion, history of malignancy conferred a higher risk of short-term mortality, but not other outcomes suggestive of surgical failure. Increased mortality after lumbar fusion should be studied further and may play a role in surgical decision-making and patient discussions.

Seasonal dynamics of the absolute and relative mass of organs of male Wistar rats at the age of 3 months

Rationale. It is relevant to develop reference values of the “norm” and their ranges in physiology and pathophysiology when using animals of genetically purebred lines in different periods of ontogenesis and in different seasons of the year. The goal was to study the parameters of absolute and relative weight of the body and organs of sexually mature male Wistar rats at the age of 3 months in different seasons. Materials and methods. The study was conducted on 160 male Wistar rats aged 3 months. During the year, seasonal indicators of absolute and relative weight of the body, brain, spleen, thymus, liver, kidneys, adrenal glands, heart, lungs, and testes were measured. Results. The most constant seasonal changes were found in the absolute mass of all organs, while the values of the relative mass factors showed seasonal variability in only 50% jf cases. Synchronous seasonal changes were noted in the kidneys and adrenal glands. Whereas the thymus and spleen were characterized by the absence of simultaneity. The most pronounced seasonal variability in both mass indicators was found in the heart. Conclusion. Absolute organ mass is one of the most sensitive parameters when studying reference values, however, changes in relative mass factors should be considered. The importance of studying both indicators is explained by the fact that changes in organ mass often precede morphological changes. This study is one of the first in Russia in which reference ranges for the mass of the main organs of a healthy genetically homogeneous Wistar rats population at the age of 3 months were established, and the trend of their seasonal changes was generalized. Further study of the main causes of changes in organ mass in combination with anatomico-pathological data is necessary.

Investigating the Impact of Host Factors on Vaccinia Virus Infection Through Single-Cell Analysis via Flow Cytometry.

To investigate the impact of a host factor on viral replication, conventional techniques involve analyzing viral replication within a homogeneous cell population engineered to uniformly express the host factor. In this chapter, we present a method to explore the intricate dynamics between host factors and vaccinia virus (VACV) infection using flow cytometry, which enables the rapid, multi-parametric analysis of individual cells in solution. Cultured cells are transfected to express a host factor fused with a fluorescent protein, followed by infection with a VACV encoding a different fluorescent reporter. Subsequently, cells are washed, fixed, and filtered for flow cytometry analysis. The data are then analyzed with flow cytometry analysis software to evaluate the influence of the host factor on various infection parameters, including the stage of viral infection and viral replication level. This method allows for the precise investigation of proviral or antiviral factor expression in relation to viral replication within a heterogeneous population of cells.

Predicting deep infection in pilon and tibial plateau fractures: a secondary analysis of the VANCO and OXYGEN trials.

To develop and validate a prediction model for a deep surgical site infection (SSI) after fixation of a tibial plateau or pilon fracture. Pooled data from 2 randomized trials (VANCO and OXYGEN). Fifty-two US trauma centers. In total, 1847 adult patients with operatively treated tibial plateau or pilon fractures who met criteria for a high risk of infection. We considered 13 baseline patient characteristics and developed and externally validated prediction models using 3 approaches (logistic regression, stepwise elimination, and machine learning). The primary prediction model outcome was a deep SSI requiring operative debridement within 182 days of definitive fixation. Our primary prognostic performance metric for evaluating the models was area under the receiver operating characteristic curve (AUC) with clinical utility set at 0.7. Deep SSI occurred in 75 VANCO patients (8%) and in 56 OXYGEN patients (6%). The machine learning model for VANCO (AUC = 0.65) and stepwise elimination model for OXYGEN (AUC = 0.62) had the highest internal validation AUCs. However, none of the external validation AUCs exceeded 0.64 (range, 0.58 to 0.64). The predictive models did not reach the prespecified clinical utility threshold. Our models' inability to distinguish high-risk from low-risk patients is likely due to strict eligibility criteria and, therefore, homogeneous patient populations.

Modeling and simulation of dielectrophoretic sorting of tenogenically differentiating mesenchymal stem cells for high throughput

Mesenchymal stem cell (MSC)-based regenerative therapies are promising for healing tendon injuries and tears, due to their potential to differentiate into tenogenic cells. However, generating homogeneous populations of tenogenically differentiated stem cells remains a big challenge, as non-differentiated cells can lead to post-transplantation complications. Therefore, a homogenous sample of tenogenically differentiated MSCs is critical for advancing tendon therapies and avoiding uncontrolled cell growth or non-tendon tissue formation (e.g., ectopic bone). This work is focused on designing and simulating a dielectrophoretic (DEP)-based label-free, microfluidic platform to selectively sort and enrich tenogenically differentiated MSCs (tMSCs) from undifferentiated MSCs. Using particle tracing, creeping flow (transport of diluted species model), and electric current physics modules in the COMSOL Multiphysics simulation software package, the sorting was simulated within a two-stage microfluidic device operating at a sinusoidal frequency of 160 kHz. The optimal separation efficiency and purity are achieved at an inlet velocity of 400–1000 μm/s, with specific voltage configurations, enabling recovery of one million tMSCs in ∼3 h. Results demonstrate a near-linear relation between recovery time and particle count at the outlet boundaries and selected surfaces, indicating consistent throughput across varying conditions. This study demonstrates that DEP can offer a scalable, efficient, and label-free method for enriching tMSC populations with high selectivity, enhancing more prospects for MSC-based tendon therapies and advancing the development of microfluidic sorting devices for regenerative medicine applications.

Selection and phenotypic stability of M4 mutants of pearl millet (Pennisetum glaucum (L.) R. Br.) derived from gamma rays induced mutagenesis in Niger

Gamma irradiation mutagenesis is an approach that offers a wide range of possibilities for varietal selection. In the simultaneous induction of multiple mutations to modify several plant traits. The aim of the present study was to select seed lots for four mutants of the M4 generation. An experiment was carried out in an experimental plot to purify drought-tolerant M4 genotypes based on morphological characteristics. Potential mutants MI 02/82, MI 13/63, MI 12/72, and MI 10/54 were tested in a randomized complete block design. The parameters measured were: the number of tillers, stem height, number of internodes, number and length of ears, stem and spike diameters, and cycle duration. A dendrogram was first generated to identify the homogenous subgroups. Then an analysis of variance ANOVA was conducted between individuals of the same subgroups to evaluate the variance. On morphological parameters, results showed that MI 13/63 and MI 10/54 genotypes have a homogeneous population from M4 onwards. MI 12/72 can be classified into two different subgroups according to ear length. MI 02/82, on the other hand, showed a high degree of variability at M4. These results will contribute to the selected new varieties adapted to the needs of rural producers in order to improve the productivity of pearl millet in Niger.

Population Genetics and Gene Flow in Cyphotilapia frontosa and Cyphotilapia gibberosa Along the East Coast of Lake Tanganyika

The radiation of cichlid species in the East African Great Lakes is remarkable and rapid. The population genetics of two deep-water Cyphotilapia species along the east coast of Lake Tanganyika from Burundi to southern Tanzania was determined using ddRAD-seq. A combination of ADMIXTURE, PCA, genome polarization, and 2D site frequency spectrum analyses confirmed the presence of two species, C. frontosa in the north and C. gibberosa in the south, as documented in other studies. We also found evidence of a potential hybrid zone connecting the two species at a sharp genetic cline centered in the middle of the lake and apparent introgression in both directions, but predominantly from ‘gibberosa’ into ‘frontosa’. The highest proportion of introgressed ‘gibberosa’ ancestry was present in the southernmost populations of C. frontosa collected near Karilani Island and Cape Kabogo. At the intra-specific level, there was support for between 1 and 3 populations of C. frontosa, whereas the results indicated only a single homogeneous population of C. gibberosa. The presence of different morphs in the lake despite the low levels of heterozygosity suggests that a small number of loci may be involved in the morphological variation and/or that there is a more complex interplay between genetics and the environment in different locations.