Orthopaedic and trauma research in Tanzania: A scoping review.

Tanzania is disproportionately burdened by musculoskeletal injuries as it faces unique challenges when dealing with trauma care. This scoping review aims to summarize and assess the current state of orthopaedic and trauma research in Tanzania. By identifying key themes, trends, and gaps in the literature, this review seeks to guide future research initiatives catered specifically to the needs of Tanzania's healthcare system. Utilizing the PRISMA-ScR protocol, OVID Medline, PubMed, and CINAHL databases were searched from inception to June 17, 2023, using keywords such as "Orthopaedics" "Trauma" and "Tanzania". One hundred and ninety-two eligible studies were included and the Arksey and O'Malley framework for scoping studies was followed. There was a notable growth of relevant publications from 2015 onward, with peaks in growth in the years 2019, 2021, and 2020. The studies employed diverse research methodologies, with cross-sectional (n = 41, 21%) and prospective studies (n = 39, 20%) being the most prevalent, and randomized-controlled trials being the least prevalent methodology, making up eight studies (4.2%). The most common study themes were trauma (n = 101, 52.6%), lower extremity (n = 31, 16%), and spine-related issues (n = 27, 14%). Only three studies looked at work-related injuries (1.6%). Road traffic injuries (RTIs) were the most common mechanism of trauma in 77.0% of the trauma focused studies. Fifty-three percent of the studies were conducted by a majority of Tanzanian authors. This scoping review highlights various trends in orthopaedic and trauma research in Tanzania, with a particular emphasis on road traffic-related injuries. Various gaps are explored, including a lack of research on work-related injuries and a paucity of experimental research. Our findings underline areas where future research is warranted. The future of orthopaedic and trauma care in Tanzania depends on the efforts and collaboration of both local and international stakeholders.

Labral repair, reconstruction, and augmentation improve postoperative outcomes in patients with irreparable or hypoplastic labra: A systematic review.

PURPOSE: To review the postoperative outcomes of arthroscopic surgical options in treating irreparable and hypoplastic labrum of the hip. METHODS: Three online databases (PubMed, MEDLINE, and EMBASE) were searched from database inception to June 27, 2023 to identify literature on treatment strategies for hypoplastic/irreparable acetabular labrum. Data pertaining to classification of irreparable tears or labral hypoplasia, indication for surgery, description of treatment, radiographic findings, and clinical outcomes were recorded and described. The methodological quality of included studies was assessed by the Methodological Index for Non-Randomized Studies (MINORS) criteria. RESULTS: Seven level IV case series, eleven level III retrospective cohort studies, and two level II prospective cohort studies comprising 1937 patients were included for analysis. Studies were divided into an irreparable labral group comprising 1002 patients and a hypoplastic labral group comprising 935 patients. Treatments included repair, augmentation, or reconstruction. In the irreparable group, 12 studies recorded improvement of modified Harris Hip Score (mHHS) with preoperative scores ranging from 50.3 to 67.3 and postoperative scores ranging from 76.2 to 95.0. The rate of conversion to total hip arthroplasty (THA) and rate of revision arthroscopy were 6.6% and 5.9%, respectively across all studies. In the hypoplastic group, two studies that focused on repair noted no statistical difference in mHHS for repair in hypoplastic labrum vs repair in non-hypoplastic labrum. One study showed that there was a difference in post-operative mHHS for labral repair for hypoplastic vs non-hypoplastic labrum, with repair in non-hypoplastic labrum showing superior mHHS (p â€‹< â€‹0.001). CONCLUSION: The findings of this review suggest that treatment of irreparable labra with reconstruction or augmentation results in improved patient-reported outcome measures (PROMs). For the hypoplastic labrum, primary repair also results in improvement in PROMs. Future studies focusing on the hypoplastic labra alone with an appropriate control group, rather than irreparable labral tears, are needed to properly assess patient outcomes and guide surgical indications.

Surgical techniques for medial Patellofemoral ligament reconstruction: a systematic review and meta-analysis of level I and II studies.

PURPOSE: To determine the most optimal surgical technique for medial patellofemoral ligament reconstruction (MPFLR). METHODS: Three databases MEDLINE, PubMed, and EMBASE were searched from inception to December 13th, 2022, for level I or II studies comparing MPFLR techniques. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on patient-reported outcome measures were recorded. Quality assessment was carried out using the MINORS and Cochrane Risk of Bias assessment tools. Certainty of evidence was carried out with the GRADE assessment tool. RESULTS: Ten studies comprising 723 patients (723 knees) were included in this review. The weighted mean difference in Kujala, Lysholm, and IKDC scores comparing single- and double-tunnel patellar drilling techniques was 2.66 (95% CI -1.05-6.37, p = 0.16, I2 = 0%) with moderate certainty, 0.78 (95% CI -9.02-10.58, p = 0.88, I2 = 87%) with low certainty, and 1.71 (95% CI -2.43-5.86, p = 0.42, I2 = 0%) with low certainty, respectively. Double-suture anchor patellar fixation demonstrated greater Kujala scores than transpatellar fixation (87.1 ± 2.8 vs 84.0 ± 3.8, p < 0.001) with moderate certainty. Y-shaped graft patellar fixation demonstrated superior Kujala scores to C-shaped graft patellar fixation (95.9 ± 4.7 vs 91.3 ± 9.7, p = 0.001) with moderate certainty. Augmentation of femoral fixation with polyester sutures demonstrated superior Kujala scores (97.8 ± 6.4. vs 88.0 ± 6.3, p < 0.005) with low certainty. Four-stranded grafts demonstrated greater Kujala scores than two-stranded grafts (93.5 ± 2.6 vs 91.6 ± 3.5, p = 0.01) with low certainty. CONCLUSION: The optimal MPFLR surgical technique is likely to utilize a four-stranded graft using either endobutton, double-suture anchor, or transosseous suture patellar fixation with polyester suture augmented interference screw femoral fixation. Orthopedic surgeons can consider employing such a technique to improve patient outcomes by conferring greater graft stability, strength, and function. Level of evidence Level II.

MPFL repair after acute first-time patellar dislocation results in lower redislocation rates and less knee pain compared to rehabilitation: a systematic review and meta-analysis.

PURPOSE: This study aimed to explore the efficacy of medial patellofemoral ligament (MPFL) repair versus nonoperative rehabilitation treatment on the rate of patellar redislocation and functional outcomes in skeletally mature patients with traumatic, first-time patellar dislocations. MATERIALS AND METHODS: MEDLINE, PubMed and EMBASE were searched from database inception to May 2022 for studies examining the management options for acute first-time patellar dislocations. This study was conducted in accordance with PRISMA and R-AMSTAR guidelines. Data on redislocation rates, functional outcomes including the Kujala score for anterior knee pain, and complication rates were extracted. A meta-analysis was used to pool the mean postoperative Kujala score and calculate the proportion of patients sustaining redislocations using a random effects model. Quality assessment of included studies was performed for all included studies using the MINORS and Detsky scores. RESULTS: This review included a total of 25 studies and 1,361 patients. The pooled mean redislocation rate in 15 studies comprising 798 patients in the rehabilitation group was 30% (95% CI 25-36%, I2 = 65%). Moreover, the pooled mean redislocation rate in 10 studies comprising 170 patients undergoing MPFL repair was 7% (95% CI 3-12%, I2 = 30%). The pooled mean postoperative Kujala score in 8 studies comprising 396 patients in the rehabilitation group was 82.5 (95% CI 78.3-86.8, I2 = 91%), compared to a score of 88 (95% CI 87-90, I2 = 76%) in 3 studies comprising 94 patients in the repair group. Range of motion deficits was reported in 3.8% of 893 patients in the rehabilitation group and 2.0% of 205 patients in the repair group. CONCLUSION: MPFL repair resulted in a lower rate of redislocation, less knee pain, and noninferiority with respect to a range of motion deficits compared to nonoperative treatment for the management of acute first-time patellar dislocations. LEVEL OF EVIDENCE: IV.

MPFL reconstruction results in lower redislocation rates and higher functional outcomes than rehabilitation: a systematic review and meta-analysis.

PURPOSE: To determine the effect of early MPFL reconstruction versus rehabilitation on the rate of recurrent patellar dislocations and functional outcomes in skeletally mature patients with traumatic, first-time patellar dislocation. METHODS: Three online databases MEDLINE, PubMed and EMBASE were searched from database inception (1946, 1966, and 1974, respectively) to August 20th, 2021 for literature addressing the management of patients sustaining acute first-time patellar dislocations. Data on redislocation rates, functional outcomes using the Kujala score, and complication rates were recorded. A meta-analysis was used to pool the mean postoperative Kujala score, as well as calculate the proportion of patients sustaining redislocation episodes using a random effects model. Quality assessment of included studies was performed for all included studies using the MINORS and Detsky scores. RESULTS: A total of 19 studies and 1,165 patients were included in this review. The pooled mean redislocation rate in 14 studies comprising 734 patients in the rehabilitation group was 30% (95% CI 25-36%, I2 = 67%). Moreover, the pooled mean redislocation rate in 5 studies comprising 318 patients undergoing early MPFL reconstruction was 7% (95% CI 2-17%, I2 = 70%). The pooled mean postoperative Kujala anterior knee pain score in 7 studies comprising 332 patients in the rehabilitation group was 81 (95% CI 78-85, I2 = 78%), compared to a score of 87 (95% CI 85-89, I2 = 0%, Fig. 4) in 3 studies comprising 54 patients in the reconstruction group. CONCLUSION: Management of acute first-time patellar dislocations with MPFL reconstruction resulted in a lower rate of redislocation of 7% in the reconstruction group vs 30% in the rehabilitation group and a higher Kujala score compared to the rehabilitation group. The information this review provides will help surgeons guide their decision to choose early MPFL reconstruction versus rehabilitation when treating patients with first-time patellar dislocations and may guide future studies on the topic. LEVEL OF EVIDENCE: IV.

Genetic basis and dual adaptive role of floral pigmentation in sunflowers.

Variation in floral displays, both between and within species, has been long known to be shaped by the mutualistic interactions that plants establish with their pollinators. However, increasing evidence suggests that abiotic selection pressures influence floral diversity as well. Here, we analyse the genetic and environmental factors that underlie patterns of floral pigmentation in wild sunflowers. While sunflower inflorescences appear invariably yellow to the human eye, they display extreme diversity for patterns of ultraviolet pigmentation, which are visible to most pollinators. We show that this diversity is largely controlled by cis-regulatory variation affecting a single MYB transcription factor, HaMYB111, through accumulation of ultraviolet (UV)-absorbing flavonol glycosides in ligules (the 'petals' of sunflower inflorescences). Different patterns of ultraviolet pigments in flowers are strongly correlated with pollinator preferences. Furthermore, variation for floral ultraviolet patterns is associated with environmental variables, especially relative humidity, across populations of wild sunflowers. Ligules with larger ultraviolet patterns, which are found in drier environments, show increased resistance to desiccation, suggesting a role in reducing water loss. The dual role of floral UV patterns in pollinator attraction and abiotic response reveals the complex adaptive balance underlying the evolution of floral traits.

Flowers are an important part of how many plants reproduce. Their distinctive colours, shapes and patterns attract specific pollinators, but they can also help to protect the plant from predators and environmental stresses. Many flowers contain pigments that absorb ultraviolet (UV) light to display distinct UV patterns ­ although invisible to the human eye, most pollinators are able to see them. For example, when seen in UV, sunflowers feature a 'bullseye' with a dark centre surrounded by a reflective outer ring. The sizes and thicknesses of these rings vary a lot within and between flower species, and so far, it has been unclear what causes this variation and how it affects the plants. To find out more, Todesco et al. studied the UV patterns in various wild sunflowers across North America by considering the ecology and molecular biology of different plants. This revealed great variation between the UV patterns of the different sunflower populations. Moreover, Todesco et al. found that a gene called HaMYB111 is responsible for the diverse UV patterns in the sunflowers. This gene controls how plants make chemicals called flavonols that absorb UV light. Flavonols also help to protect plants from damage caused by droughts and extreme temperatures. Todesco et al. showed that plants with larger bullseyes had more flavonols, attracted more pollinators, and were better at conserving water. Accordingly, these plants were found in drier locations. This study suggests that, at least in sunflowers, UV patterns help both to attract pollinators and to control water loss. These insights could help to improve pollination ­ and consequently yield ­ in cultivated plants, and to develop plants with better resistance to extreme weather. This work also highlights the importance of combining biology on small and large scales to understand complex processes, such as adaptation and evolution.

Adaptive and nonadaptive causes of heterogeneity in genetic differentiation across the Mimulus guttatus genome.

Genetic diversity becomes structured among populations over time due to genetic drift and divergent selection. Although population structure is often treated as a uniform underlying factor, recent resequencing studies of wild populations have demonstrated that diversity in many regions of the genome may be structured quite dissimilar to the genome-wide pattern. Here, we explored the adaptive and nonadaptive causes of such genomic heterogeneity using population-level, whole genome resequencing data obtained from annual Mimulus guttatus individuals collected across a rugged environment landscape. We found substantial variation in how genetic differentiation is structured both within and between chromosomes, although, in contrast to other studies, known inversion polymorphisms appear to serve only minor roles in this heterogeneity. In addition, much of the genome can be clustered into eight among-population genetic differentiation patterns, but only two of these clusters are particularly consistent with patterns of isolation by distance. By performing genotype-environment association analysis, we also identified genomic intervals where local adaptation to specific climate factors has accentuated genetic differentiation among populations, and candidate genes in these windows indicate climate adaptation may proceed through changes affecting specialized metabolism, drought resistance, and development. Finally, by integrating our findings with previous studies, we show that multiple aspects of plant reproductive biology may be common targets of balancing selection and that variants historically involved in climate adaptation among populations have probably also fuelled rapid adaptation to microgeographic environmental variation within sites.

Flower orientation influences floral temperature, pollinator visits and plant fitness.

Effective insect pollination requires appropriate responses to internal and external environmental cues in both the plant and the pollinator. Helianthus annuus, a highly outcrossing species, is marked for its uniform eastward orientation of mature pseudanthia, or capitula. Here we investigate how this orientation affects floral microclimate and the consequent effects on plant and pollinator interactions and reproductive fitness. We artificially manipulated sunflower capitulum orientation and temperature in both field and controlled conditions and assessed flower physiology, pollinator visits, seed traits and siring success. East-facing capitula were found to have earlier style elongation, pollen presentation and pollinator visits compared with capitula manipulated to face west. East-facing capitula also sired more offspring than west-facing capitula and under some conditions produced heavier and better-filled seeds. Local ambient temperature change on the capitulum was found to be a key factor regulating the timing of style elongation, pollen emergence and pollinator visits. These results indicate that eastward capitulum orientation helps to control daily rhythms in floral temperature, with direct consequences on the timing of style elongation and pollen emergence, pollinator visitation, and plant fitness.

Population responses to a historic drought across the range of the common monkeyflower (Mimulus guttatus).

PREMISE: Due to climate change, more frequent and intense periodic droughts are predicted to increasingly pose major challenges to the persistence of plant populations. When a severe drought occurs over a broad geographical region, independent responses by individual populations provide replicated natural experiments for examining the evolution of drought resistance and the potential for evolutionary rescue. METHODS: We used a resurrection approach to examine trait evolution in populations of the common monkeyflower, Mimulus guttatus, exposed to a record drought in California from 2011 to 2017. Specifically, we compared variation in traits related to drought escape and avoidance from seeds collected from 37 populations pre- and post-drought in a common garden. In a parallel experiment, we evaluated fitness in two populations, one which thrived and one which was nearly extirpated during the drought, under well-watered and dry-down conditions. RESULTS: We observed substantial variation among populations in trait evolution. In the subset of populations where phenotypes changed significantly, divergence proceeded along trait correlations with some populations flowering rapidly with less vegetative tissue accumulation and others delaying flowering with greater vegetative tissue accumulation. The degree of trait evolution was only weakly correlated with drought intensity but strongly correlated with initial levels of standing variation. Fitness was higher in the post-drought than pre-drought accessions in both treatments for the thriving population, but lower in both treatments for the nearly extirpated population. CONCLUSIONS: Together, our results indicate that evolutionary responses to drought are context dependent and reflect the standing genetic variation and genetic correlations present within populations.

Who are we now? A demographic assessment of three evolution societies.

Scientific societies have the potential to catalyze support for communities that have been historically excluded from science. Many of these societies have formed committees to propose and administer initiatives to promote the career and well-being of their members, with a special emphasis on racial and ethnic minorities. Yet, these societies are rarely armed with data to inform their proposals. Three of the evolution societies (American Society of Naturalists, "ASN"; Society of Systematic Biologists, "SSB"; Society for the Study of Evolution, "SSE") have also formed Diversity, Equity, and Inclusion committees in the last few years. As a first step in determining the needs of the societies, these committees collected data on the demographic characteristics of the societies' constituents by surveying the attendants of the Evolution 2019 meeting. Here, we report the proportions for different demographic groups in attendance at the meeting and compare these proportions to the demographics of recipients of Ph.D. degrees either in evolutionary biology or in the broader life sciences, as well as population demographics of the USA. Our results indicate that historically excluded groups are still underrepresented across US-based evolutionary biology professional societies. We explore whether demographic composition differs at different professional stages and find that representation for women and LGBTQ+ members decreases as the career stage progresses. We also find some evidence for heterogeneity across societies in terms of racial composition. Finally, we discuss the caveats and limitations of our procedures. Our results will serve to inform future efforts to collect demographic data at the society levels, which should in turn be used to design and implement evidence-based initiatives for inclusion and equity. This report should be a starting point for systematic efforts to characterize the ever-changing representation in evolutionary biology and to work toward the inclusion of all groups.

The Genetic Architecture of Plant Defense Trade-offs in a Common Monkeyflower.

Determining how adaptive combinations of traits arose requires understanding the prevalence and scope of genetic constraints. Frequently observed phenotypic correlations between plant growth, defenses, and/or reproductive timing have led researchers to suggest that pleiotropy or strong genetic linkage between variants affecting independent traits is pervasive. Alternatively, these correlations could arise via independent mutations in different genes for each trait and extensive correlational selection. Here we evaluate these alternatives by conducting a quantitative trait loci (QTL) mapping experiment involving a cross between 2 populations of common monkeyflower (Mimulus guttatus) that differ in growth rate as well as total concentration and arsenal composition of plant defense compounds, phenylpropanoid glycosides (PPGs). We find no evidence that pleiotropy underlies correlations between defense and growth rate. However, there is a strong genetic correlation between levels of total PPGs and flowering time that is largely attributable to a single shared QTL. While this result suggests a role for pleiotropy/close linkage, several other QTLs also contribute to variation in total PPGs. Additionally, divergent PPG arsenals are influenced by a number of smaller-effect QTLs that each underlie variation in 1 or 2 PPGs. This result indicates that chemical defense arsenals can be finely adapted to biotic environments despite sharing a common biochemical precursor. Together, our results show correlations between defense and life-history traits are influenced by pleiotropy or genetic linkage, but genetic constraints may have limited impact on future evolutionary responses, as a substantial proportion of variation in each trait is controlled by independent loci.

Phytochrome interacting factors 4 and 5 regulate axillary branching via bud abscisic acid and stem auxin signalling.

The ratio of red light to far-red light (R:FR) is perceived by phytochrome B (phyB) and informs plants of nearby competition. A low R:FR indicative of competition induces the shade avoidance syndrome and suppresses branching by incompletely understood mechanisms. Phytochrome interacting factors (PIFs) are transcription factors targeted by phytochromes to evoke photomorphogenic responses. PIF4 and PIF5 promote shade avoidance responses and become inactivated by direct interaction with active phyB in the nucleus. Here, genetic and physiological assays show that PIF4 and PIF5 contribute to the suppression of branching resulting from phyB loss of function and a low R:FR, although roles for other PIFs or pathways may exist. The suppression of branching is associated with PIF4/PIF5 promotion of the expression of the branching inhibitor BRANCHED 1 and abscisic acid (ABA) accumulation in axillary buds and is dependent on the function of the key ABA biosynthetic enzyme Nine-cis-epoxycarotenoid dioxygenase 3. However, PIF4/PIF5 function is not confined to a single hormonal pathway, as they also promote stem indole-3-acetic acid accumulation and stimulate systemic auxin signalling, which contribute to the suppression of bud growth when phyB is inactive.

Two MYB Proteins in a Self-Organizing Activator-Inhibitor System Produce Spotted Pigmentation Patterns.

Many organisms exhibit visually striking spotted or striped pigmentation patterns. Developmental models predict that such spatial patterns can form when a local autocatalytic feedback loop and a long-range inhibitory feedback loop interact. At its simplest, this self-organizing network only requires one self-activating activator that also activates a repressor, which inhibits the activator and diffuses to neighboring cells. However, the molecular activators and inhibitors fully fitting this versatile model remain elusive in pigmentation systems. Here, we characterize an R2R3-MYB activator and an R3-MYB repressor in monkeyflowers (Mimulus). Through experimental perturbation and mathematical modeling, we demonstrate that the properties of these two proteins correspond to an activator-inhibitor pair in a two-component, reaction-diffusion system, explaining the formation of dispersed anthocyanin spots in monkeyflower petals. Notably, disrupting this pattern impacts pollinator visitation. Thus, subtle changes in simple activator-inhibitor systems are likely essential contributors to the evolution of the remarkable diversity of pigmentation patterns in flowers.

Evolutionary processes from the perspective of flowering time diversity.

Although it is well appreciated that genetic studies of flowering time regulation have led to fundamental advances in the fields of molecular and developmental biology, the ways in which genetic studies of flowering time diversity have enriched the field of evolutionary biology have received less attention despite often being equally profound. Because flowering time is a complex, environmentally responsive trait that has critical impacts on plant fitness, crop yield, and reproductive isolation, research into the genetic architecture and molecular basis of its evolution continues to yield novel insights into our understanding of domestication, adaptation, and speciation. For instance, recent studies of flowering time variation have reconstructed how, when, and where polygenic evolution of phenotypic plasticity proceeded from standing variation and de novo mutations; shown how antagonistic pleiotropy and temporally varying selection maintain polymorphisms in natural populations; and provided important case studies of how assortative mating can evolve and facilitate speciation with gene flow. In addition, functional studies have built detailed regulatory networks for this trait in diverse taxa, leading to new knowledge about how and why developmental pathways are rewired and elaborated through evolutionary time.

Lagging Adaptation to Climate Supersedes Local Adaptation to Herbivory in an Annual Monkeyflower.

While native populations are often adapted to historical biotic and abiotic conditions at their home site, populations from other locations in the range may be better adapted to current conditions due to changing climates or extreme conditions in a single year. We examine whether local populations of a widespread species maintain a relative advantage over distant populations that have evolved at sites better matching the current climate. Specifically, we grew lines derived from low- and high-elevation annual populations in California and Oregon of the common monkeyflower (Erythranthe guttata) and conducted phenotypic selection analyses in low- and high-elevation common gardens in Oregon to examine relative fitness and the traits mediating relative fitness. Californian low-elevation populations have the highest relative fitness at the low-elevation site, and Californian high-elevation populations have the highest relative fitness at the high-elevation site. Relative fitness differences are mediated by selection for properly timed transitions to flowering, with selection favoring more rapid growth rates at the low-elevation site and greater vegetative biomass prior to flowering at the high-elevation site. Fitness advantages for Californian plants occur despite incurring higher herbivory at both sites than the native Oregonian plants. Our findings suggest that a lag in adaptation causes maladaptation in extreme years that may be more prevalent in future climates, but local populations still have high growth rates and thus are not yet threatened.

Plant Genomics: Evolution and Development of a Major Crop Parasite.

Parasitic plants in the genus Striga bedevil crop production throughout Africa and Asia. A new genome assembly reveals how repurposing of developmental pathways, gene gains and losses, and horizonal gene transfer all contributed to the evolution of these destructive pathogens.

GOOGA: A platform to synthesize mapping experiments and identify genomic structural diversity.

Understanding genomic structural variation such as inversions and translocations is a key challenge in evolutionary genetics. We develop a novel statistical approach to comparative genetic mapping to detect large-scale structural mutations from low-level sequencing data. The procedure, called Genome Order Optimization by Genetic Algorithm (GOOGA), couples a Hidden Markov Model with a Genetic Algorithm to analyze data from genetic mapping populations. We demonstrate the method using both simulated data (calibrated from experiments on Drosophila melanogaster) and real data from five distinct crosses within the flowering plant genus Mimulus. Application of GOOGA to the Mimulus data corrects numerous errors (misplaced sequences) in the M. guttatus reference genome and confirms or detects eight large inversions polymorphic within the species complex. Finally, we show how this method can be applied in genomic scans to improve the accuracy and resolution of Quantitative Trait Locus (QTL) mapping.

Ancient DNA reveals the timing and persistence of organellar genetic bottlenecks over 3,000 years of sunflower domestication and improvement.

Here, we report a comprehensive paleogenomic study of archaeological and ethnographic sunflower remains that provides significant new insights into the process of domestication of this important crop. DNA from both ancient and historic contexts yielded high proportions of endogenous DNA, and although archaeological DNA was found to be highly degraded, it still provided sufficient coverage to analyze genetic changes over time. Shotgun sequencing data from specimens from the Eden's Bluff archaeological site in Arkansas yielded organellar DNA sequence from specimens up to 3,100 years old. Their sequences match those of modern cultivated sunflowers and are consistent with an early domestication bottleneck in this species. Our findings also suggest that recent breeding of sunflowers has led to a loss of genetic diversity that was present only a century ago in Native American landraces. These breeding episodes also left a profound signature on the mitochondrial and plastid haplotypes in cultivars, as two types were intentionally introduced from other Helianthus species for crop improvement. These findings gained from ancient and historic sunflower specimens underscore how future in-depth gene-based analyses can advance our understanding of the pace and targets of selection during the domestication of sunflower and other crop species.

Plant Domestication: Wild Date Palms Illuminate a Crop's Sticky Origins.

In a new study, previously unknown populations of wild date palm have been identified in remote areas of Oman. Genomic analyses indicate date palm domestication occurred in the eastern portion of the Arabian Peninsula and reveal substantial subsequent gene flow with African palm populations.