Intrapopulation Variation Research Articles

Analysis of Upper Airway Flow Dynamics in Robin Sequence Infants Using 4-D Computed Tomography and Computational Fluid Dynamics.

Robin Sequence (RS) is a potentially fatal craniofacial condition characterized by undersized jaw, posteriorly displaced tongue, and resultant upper airway obstruction (UAO). Accurate assessment of UAO severity is crucial for management and diagnosis of RS, yet current evaluation modalities have significant limitations and no quantitative measures of airway resistance exist. In this study, we combine 4-dimensional computed tomography and computational fluid dynamics (CFD) to assess, for the first time, UAO severity using fluid dynamic metrics in RS patients. Dramatic intrapopulation differences are found, with the ratio between most and least severe patients in breathing resistance, energy loss, and peak velocity equal to 40:1, 20:1, and 6:1, respectively. Analysis of local airflow dynamics characterized patients as presenting with primary obstructions either at the location of the tongue base, or at the larynx, with tongue base obstructions resulting in a more energetic stenotic jet and greater breathing resistance. Finally, CFD-derived flow metrics are found to correlate with the level of clinical respiratory support. Our results highlight the large intrapopulation variability, both in quantitative metrics of UAO severity (resistance, energy loss, velocity) and in the location and intensity of stenotic jets for RS patients. These results suggest that computed airflow metrics may significantly improve our understanding of UAO and its management in RS.

Genetic diversity and verbascoside content in natural populations of Pyrostegia venusta (Ker Gawl.) Miers.

Pyrostegia venusta (Ker Gawl.) Miers occurs in threatened biodiversity hotspots of Cerrado and Atlantic forest biomes in Brazil and is used in traditional medicine to treat various respiratory and skin diseases. This study (i) examined the genetic diversity and structure of six natural populations of P. venusta from different Brazilian regions using sequence-related amplified polymorphism (SRAP) markers; and (ii) compared the intra- and inter-populational levels of the bioactive component verbascoside using high-performance liquid chromatography. The population from Nova Mutum, Mato Grosso, presented the highest genetic variability (Nei index H = 0.2759; Shannon index I = 0.4170; 85.14% polymorphic loci), whereas the population from Araxá, Minas Gerais, presented the lowest genetic variability (H = 0.1811; I = 0.2820; 70.27% polymorphic loci). The intra-populational variability (79%) was significantly higher (p = 0.001) than the inter-populational variability (21%). The populations were clustered into two groups but their genetic differentiation was not associated with geographical origin (Mantel test, r = 0.328; p > 0.05). The verbascoside content significantly differed (p > 0.05) among the six populations and between the individuals from each population. The highest verbascoside levels (> 200µg/mg extract) were detected in populations from Araxá and Serrana, while the lowest verbacoside levels were detected in populations from Paranaíta and Sinop. This is the first report on the use of SRAP markers to analyze genetic variability in the family Bignoniaceae. Our findings shall help to better understand the genetic and chemical diversity of P. venusta populations, as well as provide useful information to select the most appropriate individuals to prepare phytomedicines.

Intra-population variability of oil content and fatty acid composition in modern hemp cultivars

Purpose and objectives. To identify new promising material with high seed productivity, oil content and optimal fatty acid composition
 Results and discussion. It was found that the variability ranges of the oil content and seed weight increased under the influence of selections. Use of distant genotypes in hybridization contributed to the generation of high-oil lines, which later become donors of this trait. High oil content was recorded in hybrids derived from crossing cultivars and self-pollinated lines of the Central European eco-geographical type with cultivars and self-pollinated lines of the southern type. In this case, cultivar-line and line-cultivar hybrids (oil content of 36−39%), rather than inter-line ones, turned out to be the most successful results.
 Family-group selection is a basis for increasing and further stabilizing the oil content in seeds. The oil content was revealed to gradually increase during the breeding for increased oil content. It was found that the population variability of the seed oil content was from 33.99% to 46.98%.
 Continuous breeding selection gradually widens the expression range of the “oil content” trait from medium to maximum. In order to increase the practical value of cultivars via breeding techniques the seed productivity was also increased. The cultivars of different genetic origins, Hlesiia and Mykolaiychyk, as well as the cultivars of hybrid origin, Artemida and Harmoniia, were considered the most promising ones. In Mykolaichyk populations, the oil content gradually increased and stabilized at a level of 33, 35, or 37.8% without changes in the fatty acid composition of oil.
 The selections stabilized the oil content in cultivar populations. This proves the high efficiency of the developed breeding methods to create cultivars with high seed productivity and of targeted selection to increase the oil content in hemp seeds. Thus, the importance of a cultivar combining high seed yield and high oil output rises. The modern cultivars were ranked in order of decreasing oil levels in seeds as follows: Mykolaichyk, Artemida, Harmoniia, Hlesiia.
 Oil of all cultivars had an optimal ratio of omega-3 to omega 6 fatty acids of 1:3.1−1:3.9 (2016−2017). In 2018−2019, the ratio of omega-6 to omega-3 fatty acids was 4.0:1− 4.8:1. The linoleic acid content ranged from 55% to 58% and the linolenic acid content – from 12.58% to 18.23%. Mykolaichyk and Artemida were noticeable for gamma-linolenic acid. These results allow us to assert that the fatty acid composition of hemp seeds is unique and immutable during the breeding for increased oil content.
 Conclusions. We believe that the Central European type is a source and donor of high oil content, while the southern type – of a longer seed formation and, accordingly, of high oil accumulation.
 The heterosis phenomenon resulted from combining distant genotypes in one organism was observed. In this case, cultivar-line and line-cultivar hybrids, but not inter-line hybrids, turned out to be the most successful ones (oil content of 36−39%).
 The new hemp cultivars, Mykolaichyk, Artemida and Harmoniia, which combine high seed productivity with high seed oil content and unique fatty acid composition, have been created.

INDIVIDUAL VARIABILITY OF SIBERIAN SPRUCE CONES AND SEEDS IN THE MIDDLE REACHES OF THE SEVERNAYA SOSVA RIVER (KHANTY-MANSI AUTONOMOUS OKRUG)

Individual (intrapopulation) variability of cones and seeds of Siberian spruce in the north-west of the Khanty-Mansi Autonomous Okrug in the middle reaches of the Severnaya Sosva River corresponds to "typical" values for the species in a number of traits. At the same time, increased values of the weight of 100 full seeds were noted: 0.547 (0.445-0.644) g and the number of cotyledons associated with it (6.9-8.0 pcs). The coefficient of variation of the first trait is 10 %, the second - about 4 %. The average length of cones on different trees is in the range of 49-80 mm. Seed germination and especially germination readiness have an increased variability. The duration of the seed germination period is on average 11 days, the coefficient of variation is about 12 %; it is 2-4 times less than the coefficient of variation of seed germination and germination readiness. The mass of 100 seeds is associated with the length of cones and the number of cotyledons by a reliable correlation of the average level. A closer relationship (the correlation coefficient is 0.55-0.77) was found between the germination readiness and seed germination. The results of the study contain new information about the regional biological features of Siberian spruce and may be of interest to forestry.

Admixture and population dynamics in the Philippines through craniometric analysis

The Philippine population prior to European contact is the result of the arrival to the archipelago of different subgroups and the admixture between them. Taking the skull as a complex genotype resulting from both genetic inheritance and the environment, and assuming populations with phenotypic similarity will have a greater phylogenetic relationship, the possibility of studying admixture based on geometric morphometry and cranial measurements is proposed. Sixty-one skulls from a collection from the National Museum of Anthropology in Madrid (MNA, Spain) were studied, all dating from before the 19th century. As a reference, the Howells (1973) database was used. The characterization of the phenotype was carried out using a Microscribe digitizer arm with which 65 landmarks were taken, using them to create 12 craniometric distances. The admixture of the Philippine skull collection from the MNA was evaluated by applying a Discriminant Analysis based on Gaussian finite mixture modeling. Thanks to a Principal Component Analysis, a study of morphospaces was carried out. Additionally, a population inference was made using the Relethford and Blangero model. Finally, the skulls were divided into clusters according to their admixture using the k-means method. The individual admixture of each skull was estimated, and later the collection was divided into three clusters after applying the k-means method. The Relethford and Blangero analysis indicated that the groups created did not have much internal admixture, unlike the Filipino group in the Howells database. Assuming a relative neutrality of the craniofacial characters, it is possible to study the admixture of some individuals from a series of cranial distances. This study is framed in the line of other genetic, linguistic, or morphometric types, which indicate that the Philippine population prior to the 19th century has a great intrapopulation variance, constituting a series of metapopulations within the entire archipelago.

Genetic variation of the interaction type between two stressors in a single population: From antagonism to synergism when combining a heat spike and a pesticide

Despite the surging interest in the interactions between toxicants and non-chemical stressors, and in evolutionary ecotoxicology, we have poor knowledge whether these patterns differ among genotypes within a population. Warming and toxicants are two widespread stressors in aquatic systems that are known to modify each other's effects. We studied to what extent effects of sequential exposure to a heat spike and the pesticide esfenvalerate differed among genotypes in the water flea Daphnia magna. Esfenvalerate had similar negative effects on survival and body size across genotypes, and for most genotypes it increased time to maturation, yet the effects on the reproductive performance were only detected in some genotypes and were inconsistent in direction. Across genotypes, the heat spike increased the heat tolerance, yet the negative effects of the heat spike on survival, reproductive performance and body size, and the positive effects on grazing rate and the shortened time to maturation were only seen in some genotypes. Notably, the interaction type between both stressors differed among genotypes. In contrast to our expectation, the impact of esfenvalerate was only magnified by the heat spike in some genotypes and only for a subset of the traits. For survival and time to maturation, the interaction type for the same stressor combination covered all three categories: additions, synergisms and antagonisms. This illustrates that categorizing the interaction type between stressors at the level of populations may hide considerable intrapopulation variation among genotypes. Opposite to our expectation, the more pesticide-tolerant genotypes showed a stronger synergism between both stressors. Genotype-dependent interaction patterns between toxicants and non-chemical stressors may explain inconsistencies among studies and challenges ecological risk assessment based on single genotypes. The observed genetic differences in the responses to the (combined) stressors may fuel the evolution of the stressor interaction pattern, a largely ignored topic in evolutionary ecotoxicology.

Comparative Genetic Diversity Analysis for Biomass Allocation and Drought Tolerance in Wheat

Genetic diversity is invaluable in developing climate-smart and drought-adapted wheat varieties. The aim of this study was to determine the extent of genetic variation present in wheat germplasm collections for biomass allocation and drought tolerance based on complementary phenotypic and root attributes and high-density single nucleotide polymorphism (SNP) markers to select breeding parents. A total of 97 bread wheat (Triticum aestivum L.) genotypes were evaluated in field and greenhouse trials under drought-stressed and non-stressed conditions. The molecular variance analysis showed that the intrapopulation variance was very high at 99%, with a small minimal inter-population variance (1%). The genetic distance, polymorphic information content and expected heterozygosity were 0.20–0.88, 0.24–1.00 and 0.29–0.58, respectively. The cluster analysis based on SNP data showed that 44% and 28% of the assessed genotypes maintained their genetic groups when compared to hierarchical clusters under drought-stressed and non-stressed phenotypic data, respectively. The joint analysis using genotypic and phenotypic data resolved three heterotic groups and allowed the selection of genotypes BW140, BW152, BW157, BW162, LM30, LM47, LM48, LM52, LM54 and LM70. The selected genotypes were the most genetically divergent with high root biomass and grain yield and are recommended for production or breeding.

Türkiye'nin güneybatısındaki istilacı Coptodon (Perciformes: Cichlidae): Dizi verileri kullanılarak tür tanımlaması

Nonnative cichlids (Coptodon zillii) have established populations in the Köyceğiz and Koca Lakes, located on the west coasts of Mediterranean Turkey. Conflicting species names in these lakes have been reported for many years. We studied samples from current populations of Coptodon in these lakes and the Pecenek canal concerning existing GenBank data. We estimated the possible ancestral population using sequence data in the mitochondrial D-loop segment. Inter and intra-population morphological variations of Coptodon were examined using 25 morphological and six meristic characters. Haplotype analysis revealed three unique haplotypes in three populations of Coptodon, indicating poor genetic diversity. Both maximum likelihood and Bayesian trees showed that these three haplotypes constitute a distinct subclade within the Coptodon zillii clade. This phylogenetic pattern indicates that populations of both lakes were founded by a single invasion of C. zillii and belong to a single species. Consistent with phylogenetic data, the populations of both lakes do not exhibit significant phenotypic divergence, though the Pecenek population is slightly divergent. Intra-population morphological variability may be due to phenotypic plasticity in response to habitat heterogeneity within the lakes.

A structural reassessment of the Late Pleistocene femur from Maludong, southwestern China

AbstractObjectiveThe Late Pleistocene partial right femur from Maludong in southwestern China has been attributed characteristics of early Homo, especially from the Early Pleistocene, putatively representing a late surviving archaic population in the region. Assessment of additional traits is warranted given newly described postcrania from the Late Pleistocene of southwestern China and characterized by relatively modern features.Materials and methodsWe used micro computed tomography (μCT) to extract and evaluate cross‐sectional diaphyseal structure. New predictions of Maludong femoral length were generated from a regression analysis of Holocene modern humans. Robusticity and shape at multiple, standard diaphyseal regions of interest (ROI) were compared to those of Pleistocene and Holocene humans from East Asia and beyond.ResultsStandardized torsional rigidities at mid‐proximal and subtrochanteric Maludong ROIs fell within ranges of variation exhibited by multiple comparative groups, and closest to medians of Early and Middle Upper Paleolithic modern humans (E/MUP). For Ix/Iy diaphyseal ratios, Maludong was higher than comparative groups at both ROIs, falling closest to the upper end of the E/MUP range. For Imax/Imin shape ratios, Maludong fell well above group medians at the mid‐proximal ROI and nearest E/MUP and Middle Pleistocene group medians at the subtrochanteric ROI.Discussion and conclusionsIn diaphyseal robusticity and rigidity ratios, Maludong fits within variation exhibited by other Late Pleistocene modern humans. While we did not re‐analyze external features described as archaic‐like, internal structure of the Maludong femur contradicts this characterization and instead supports expanding intrapopulation variability expressed by Late Pleistocene modern humans in East Asia.

Morphometric and Phylogenetic analysis of morphotypes in Artemia franciscana Kellogg, 1906 (Crustacea: Anostraca)

We document morphology and genetic relatedness of morphotypes within the Artemia franciscana that has colonized Covelong saltern in Kelambakkam (South India). They exhibits high phenotypic plasticity and intra-population variation in a supposedly panmictic population. Morphometric analysis was carried out on 18 traits in males and 15 in females and subjected to multivariate analysis. Three types each in males (M1, M3 and M4) and females (F1, F2 and F3) were singled out. The axes in the plot explain 77.9% in males and 73.9% in females of the variation through discriminant function analysis. The sequence divergence of the population was evaluated through mtDNA (16S rRNA) and nDNA (p26 gene) markers. The substantial sequence divergence was observed between the morphotypes through nDNA and appearing sequence divergence was recognized by mtDNA. Likewise, phylogenetic analyses of maximum likelihood and Bayesian analysis through nDNA revealed a maximum similarities between M1, M4 with F1 & F2 and M3 with F3. Further, haplotype distribution of nDNA revealed unique haplotype between M1 and M4 with F1 and F2 morphotypes. This study thus confirms the occurrence of morphotypes with specific characteristics inside a seemingly homogeneous population.

Varijabilnost generativnog potomstva klena (Acer campestre L.) u rasadničkom testiranju

Field maple (Acer campestre L.) is naturally distributed in most of Europe, with the exception of its northern parts. Field maple can serve as a valuable model for researching the sensitivity of its populations to habitat fragmentation, considering lack of silvicultural treatments in its stands. The research aims to determine interpopulation and intrapopulation variability of field maple populations from Bosnia and Herzegovina in the nursery test. The authors researched measured root collar diameter, height, observed forkness and calculated slenderness coefficient of the one-year-old generative material from 18 Bosnian-Herzegovinian populations of field maple, produced in the nursery of Žepče. The descriptive statistics and variance analysis was performed. All analyzed traits showed a high degree of intra-population as well as interpopulation variability, as confirmed by the analysis of variance. The highest average height had provenance Bosanski Brod (46.08 cm) and the smallest Bosanska Dubica (19.11 cm). Kreševo provenance had the highest average root neck diameter (8.27 mm) and Bosanska Dubica (5.24 mm) the lowest. A very low percentage of forkness (6.86%) was determined, and the values of the slenderness coefficient were acceptable for all provenances. The results indicate need for further systematic research on this ecologically valuable species.

Genetic diversity, redundancy and population structure in flax (Linum usitatissimum L.) as revealed by dominant molecular marker system

In the present investigation, RAPD profiling was employed to estimate the genetic diversity, population structure and linkage disequilibrium in 232 flax germplasm which were divided into three population viz. CRIJAF population, NBPGR population and CSKHPKV population based on their source of collection. The RAPD markers generated total 122 allele out of which 72 showed polymorphism (61.83 %) with mean effective number of allele, PIC, MI, RP value as 1.14, 0.13, 21.39 and 1.59 respectively. The RAPD primers also exhibited the highest Nei’s gene diversity (h) and Shannon’s diversity index (I) in CRIJAF population (h = 00.116 and I = 0.206) followed by CSKHPKV and NBPGR population, with a low level of overall genetic variability (h = 0.107 and I = 0.187). AMOVA illustrated that 14% of the total genetic variability was originated due to inter population whereas the remaining 80% of the total variability arose within the populations. The overall relative magnitude of genetic differentiation among the populations was 0.15 and also high level of gene flow between the populations was observed. The results of population structure analysis proposed that total flax accessions were distributed into nine genetic groups. Phylogenetic tree also successfully identified the redundant genotypes from the total flax accession. LD analysis indicated narrow inter-population genetic variation and higher level of intra-population genetic variation in flax. The findings of the present investigation will be helpful for utilization of flax germplasm in future crop improvement programme and association mapping.

One Cell at a Time: Advances in Single-Cell Methods and Instrumentation for Discovery in Aquatic Microbiology.

Studying microbes from a single-cell perspective has become a major theme and interest within the field of aquatic microbiology. One emerging trend is the unfailing observation of heterogeneity in activity levels within microbial populations. Wherever researchers have looked, intra-population variability in biochemical composition, growth rates, and responses to varying environmental conditions has been evident and probably reflect coexisting genetically distinct strains of the same species. Such observations of heterogeneity require a shift away from bulk analytical approaches and development of new methods or adaptation of existing techniques, many of which were first pioneered in other, unrelated fields, e.g., material, physical, and biomedical sciences. Many co-opted approaches were initially optimized using model organisms. In a field with so few cultivable models, method development has been challenging but has also contributed tremendous insights, breakthroughs, and stimulated curiosity. In this perspective, we present a subset of methods that have been effectively applied to study aquatic microbes at the single-cell level. Opportunities and challenges for innovation are also discussed. We suggest future directions for aquatic microbiological research that will benefit from open access to sophisticated instruments and highly interdisciplinary collaborations.

Variación fenotípica intrapoblacional en quinua en el departamento de Boyacá, Colombia

Quinoa (Chenopodium quinoa Wild.) is an Andean crop that originated from the Andes of South America, with great agronomic, industrial, pharmaceutical potential and also a great capacity to tolerate adverse environmental factors. In Colombia, more accurately in the Department of Nariño, Cauca, Cundinamarca and Boyacá. Shows great genetic variation, both molecular and morphological, which organization remains poorly documented. In Boyacá, there are few studies on the morphological characterization of cultivated materials, and there is no certified planting material, with farmers planting a mixture of materials. Qualitative and quantitative descriptors and principal component and cluster analyses were used to characterize the structure of the intra-population phenotypic variation in Blanca de Jericó quinoa materials grown in the Department of Boyacá. The principal component analysis explained more than 70 % of the observed variation, with the AP, LP, DP, LHS, and AHS characteristics being more variable. The cluster analysis showed grouping by characteristics, such as AP, panicle color, and the presence of pigmented axillae. Results show that the variance in morpho-phenological traits was concentrated at the intra-population, due to high variation at the inter-individual level. A more efficient selection process should be carried out to find materials or "pure" varieties with higher yields, resistance to biotic and abiotic factors, and adaptation to local conditions, which make quinoa an economically profitable crop in the Boyacá department.

From Cone to Seed and Seedling—Characterization of Three Portuguese Pinus pinaster Aiton Populations

Seed production in Pinus pinaster Aiton is not usually considered a limiting factor for natural regeneration; instead, seed weight is a more limiting factor in successful pine recruitment. Divergent relationships between seed weight and germination rate were previously observed amongst maritime pine populations of central coastal Portugal. The present study followed cone-to-seed and seed-to-seedling approaches to decrease intra-specific variability and clarify the impact of cone size and seed mass on seedling recruitment. The main objectives of this study were (1) to determine and compare the mass of cones and seeds of three maritime pine populations located along a geographic gradient along the coastal center of Portugal and (2) to clarify the relations thereof between cone and seed traits with germination phenology and initial seedling growth. Results demonstrated that heavier cones tended to generate more mature seeds, but not necessarily heavier ones, although seed weight was suggested to be an indicator of robust seedlings. The outcomes of this study reinforce the great intra-population variability of maritime pine, showing the ecology of this species and its ability to adapt to various environments successfully.

Analyses of genetic diversity and population structure in cultivated and wild korarima [Aframomum corrorima (Braun) P. C. M. Jansen] populations from Ethiopia using inter simple sequence repeats markers

Korarima (Aframomum corrorima) is one of the most threatened native spices and medicinal plant species of Ethiopia. Assessing its genetic diversity is critical to assist the breeding and conservation efforts of this crop. Information on the extent of its genetic diversity and population structure is very little. Hence, the present study was initiated to analyze the extents of genetic diversity of the crop using 12 cultivated and two wild A. corrorima populations and one related species called A. zambesiacum using nine inter simple sequence repeats markers. The populations were collected from 12 administrative zones of Ethiopia. Accordingly, nine ISSR primers were selected and generated a total of 109 scorable DNA bands. A total of 104 scorable bands were found to be polymorphic and reproducible. The markers showed a high level of mean percentage of polymorphic loci (PPL) (94.73%), mean expected heterozygosity (H) (0.49), and higher polymorphic information content (PIC) (0.60). Similarly, the study samples revealed higher extents of genetic diversity as evidenced from mean Nei’s gene diversity (H) (0.36) and mean Shannon’s diversity index (I) (0.48). Two and five private loci (Ap) were observed from cultivated and wild A. corrorima populations respectively while nine private loci were detected in A. zambesiacum population. Analysis of molecular variance (AMOVA) showed 64.8% intra-population variations and 34.2% inter-population variations. The AMOVA also revealed that variation among populations was highly significant (P < 0.001) which was supported by the relatively lower extent of gene differentiation (GST = 0.41) and high gene flow (Nm = 1.62). A dendrogram based on unweighted pair-group method with arithmetic mean (UPGMA) grouped the 15 populations into six clusters revealing strong pattern of geographic origin with some cases of intermixing among members of different populations. Similarly, the populations were grouped into three sub-populations. In general, the extents of genetic diversity in A. corrorima populations of the southern and southwestern parts of Ethiopia look high. West Omo, Sheka, Gofa and Basketo populations revealed the highest genetic diversity. Thus, these zones should be used as key sites in designing conservation strategies for korarima.

Assessing the Speciation of Lutjanus campechanus and Lutjanus purpureus through Otolith Shape and Genetic Analyses

Based on their morphological and genetic similarity, several studies have proposed that Lutjanus campechanus and Lutjanus purpureus are the same species, but there is no confirmed consensus yet. A population-based study concerning otolith shape and genetic analyses was used to evaluate if L. campechanus and L. purpureus are the same species. Samples were collected from populations in the southwestern Gulf of Mexico and the Venezuelan Caribbean. Otolith shape was evaluated by traditional and outline-based geometric morphometrics. Genetic characterization was performed by sequencing the mtDNA control region and intron 8 of the nuclear gene FASD2. The otolith shape analysis did not indicate differences between species. A nested PERMANOVA identified differences in otolith shape for the nested population factor (fishing area) in morphometrics and shape indexes (p = 0.001) and otolith contour (WLT4 anterior zone, p = 0.005 and WLT4 posterodorsal zone, p = 0.002). An AMOVA found the genetic variation between geographic regions to be 10%, while intrapopulation variation was 90%. Network analysis identified an important connection between haplotypes from different regions. A phylogenetic analysis identified a monophyletic group formed by L. campechanus and L. purpureus, suggesting insufficient evolutionary distances between them. Both otolith shape and molecular analyses identified differences, not between the L. campechanus and L. purpureus species, but among their populations, suggesting that western Atlantic red snappers are experiencing a speciation process.

About inter- and intra-specific variability of dental microwear texture in rodents: Study of two sympatric Proechimys (Echimyidae) species from the Cacao locality, French Guiana

Material properties of the diet of extant species is reflected by the microwear texture recorded on the enamel tooth surface, a signal that can be useful for estimating the diets of extinct species. Intra-specific dietary variations can occur between sexes or depend on seasonal vegetation cover changes in their habitat. However, these factors cannot, or very rarely, be incorporated within a paleontological context, especially if the fossil record of an extinct species is mainly composed of isolated teeth. In order to assess the effects of these factors on microwear texture features, we studied 42 wild-caught specimens of two sympatric extant species of caviomorph rodents, Proechimys cuvieri and Proechimys guyannensis (Echimyidae, Octodontoidea) from the Cacao area located in French Guiana. Animals were captured between 2007 and 2012, in July and October, along a 1.5 km transect ranging from an old secondary forest to a disturbed forest. We applied a Scale Sensitive Fractal Analysis (SSFA) to the first upper molars of these specimens. Differences of dental microwear textures were found between sexes, between months, and between habitat, leading to one species overlapping in microwear texture parameter space with the other in some cases. The results obtained help identifying which factors might drive intra-population variations in dental microwear texture. Its understanding is indeed a key-step to better interpret the dispersion observed within a given fossil sample set to obtain refined dietary reconstructions. • Dental microwear shows intra- and interspecific differences in sympatric rodents • Intraspecific variability of dental microwear can lead to interspecific overlapping • Dental microwear is not always most impacted by primary component of the diet • Intraspecific variability should be considered in dental microwear interpretations

Isotopic (δ15N and δ13C) profiles in dentine indicate sex differences and individual variability in resource use among narwhals (Monodon monoceros)

AbstractWhile the impact of ecological changes on Arctic marine mammals remains largely unknown, quantifying variability in resource use among conspecifics can serve as an indication of adaptive plasticity and help assess species vulnerability to climate‐induced changes. We measured within‐tooth δ15N and δ13C profiles of narwhals (Monodon monoceros) sampled 35 years apart from Baffin Bay, Nunavut, Canada, to evaluate intrapopulation variation in narwhal resource use. Narwhal dentine δ15N and δ13C were lower post‐1983 (n = 7) by 0.83‰ and 0.52‰, respectively, compared to pre‐1983 (n = 13), but isotopic niche breadth increased from 0.95‰2 to 1.12‰2. Between sexes, the isotopic niche of males expanded from pre‐1983 to post‐1983 while that of females decreased, which may indicate increased flexibility in resource use for males and the opposite for females. Additional isotopic variation among narwhals (n = 23) suggests individual differences in diet composition and/or foraging location during both periods. Individual isotopic niches ranged between 0.08‰2 and 2.27‰2, where a larger isotopic niche likely indicates more variable foraging strategies over time. Narwhal as a species is considered vulnerable to ecosystem change; however, the variability in resource use between sexes and among individuals suggests narwhals may vary in their adaptability to changing Arctic conditions.

Genetic variability and population genetic structure in autotriploid saffron using allelic phenotypes of microsatellite markers

A comprehensive effort was made to characterize potential inter- and intra-population genetic variation governing on the saffron ecotypes originating from 18 distinct geographical regions of Iran (90 accessions) using “allelic phenotypes” of 16 microsatellite markers. The 11 SSR loci (69%) that were polymorphic across the 90 saffron genotypes produced 30 alleles, of which ABRII/CS2 was the most informative locus. Both PCoA and UPGMA phylogenetic tree, alongside Bayesian model-based clustering grouped the 18 ecotypes into three major groups, with similar classification patterns, and highly consistent with geographical distribution. The assignment test accurately assigned 83 out of 90 saffron accessions (92.22%) to the corresponding populations, while the remainder were placed in adjacent populations. The AMOVA results revealed a high level of genetic variation within saffron populations (>80%), with a small fraction among populations (<20%). For the entire 90 accessions, significant correlation was detected between genetic and geographical distances (Mantel test, r = 0.173; P = 0.038). The results, overall, indicated the efficacy of allelic phenotypes-assisted DNA fingerprinting approach in making discrimination and unraveling potential genetic diversity among various Iranian saffron ecotypes, and possibly other autopolyploid crops.