Morphological and genomic characterisation of the Schistosoma hybrid infecting humans in Europe reveals admixture between Schistosoma haematobium and Schistosoma bovis.

Schistosomes cause schistosomiasis, the world's second most important parasitic disease after malaria in terms of public health and social-economic impacts. A peculiar feature of these dioecious parasites is their ability to produce viable and fertile hybrid offspring. Originally only present in the tropics, schistosomiasis is now also endemic in southern Europe. Based on the analysis of two genetic markers the European schistosomes had previously been identified as hybrids between the livestock- and the human-infective species Schistosoma bovis and Schistosoma haematobium, respectively. Here, using PacBio long-read sequencing technology we performed genome assembly improvement and annotation of S. bovis, one of the parental species for which no satisfactory genome assembly was available. We then describe the whole genome introgression levels of the hybrid schistosomes, their morphometric parameters (eggs and adult worms) and their compatibility with two European snail strains used as vectors (Bulinus truncatus and Planorbarius metidjensis). Schistosome-snail compatibility is a key parameter for the parasites life cycle progression, and thus the capability of the parasite to establish in a given area. Our results show that this Schistosoma hybrid is strongly introgressed genetically, composed of 77% S. haematobium and 23% S. bovis origin. This genomic admixture suggests an ancient hybridization event and subsequent backcrosses with the human-specific species, S. haematobium, before its introduction in Corsica. We also show that egg morphology (commonly used as a species diagnostic) does not allow for accurate hybrid identification while genetic tests do.

Creating Avian Forebrain Chimeras to assess Facial Development.

The avian embryo has been used as a model system for more than a century and has led to fundamental understanding of vertebrate development. One of the strengths of this model system is that the effect of, and interaction among, tissues can be directly assessed in chimeric embryos. We have previously shown that signals from the forebrain contribute to facial morphogenesis by regulating the shape of the expression domain of Sonic hedgehog (SHH) in the Frontonasal Ectodermal Zone (FEZ). In this article, the method of generating the forebrain chimeras and provide illustrations of the outcomes of these experiments is described.

Symptoms and yield loss caused by rice stripe mosaic virus.

BACKGROUND: Rice stripe mosaic virus (RSMV) is a tentative new Cytorhabdovirus species in family Rhabdoviridae transmitted by the leafhopper Recilia dorsalis. Although the virus was first detected in southern China in 2015, few studies have investigated rice symptoms and yield losses caused by RSMV infection. METHODS: In this study, we observed and systematically compared symptoms of three virally infected, representative varieties of indica, hybrid and japonica rice and determined the yield parameters of the artificially inoculated plants. RESULTS: The three RSMV-infected cultivated rice varieties exhibited slight dwarfing, striped mosaicism, stiff, crinkled or even twisted leaves, an increased number of tillers, delayed heading, cluster-shaped shortening of panicles and mostly unfilled grains. Slight differences in symptom occurrence time were observed under different environmental conditions. For example, mosaic symptoms appeared earlier and crinkling symptoms appeared later, with both symptoms later receding in some infected plants. Yield losses due to RSMV also differed among varieties. The most serious yield reduction was experienced by indica rice (cv. Meixiangzhan), followed by hybrid indica rice (cv. Wuyou 1179) and then japonica (cv. Nipponbare). Single panicle weight, seed setting rate and 1000-kernel weight were reduced in the three infected varieties compared with healthy plants-by 85.42, 94.85 and 31.56% in Meixiangzhan; 52.43, 53.06 and 25.65% in Wuyou 1179 and 25.53, 49.32 and 23.86% in Nipponbare, respectively. CONCLUSIONS: Our findings contribute basic data for field investigations, formulation of prevention and control strategies and further study of the pathogenesis of RSMV.

Features inheritance of root system Arabidopsis thaliana (L.) Heynh. the interaction of genes CTR1 AND ALF3, NPH4 and IAR2.

The results of study interaction of genes CTR1, ALF3 and NPH4, IAR2 inheritance attributes of the root system Arabidopsis. It is set that there is a recession epistasis in the second generation of crossing of plants mutant lines ctr1-1 × alf3-1 (alf3-1 alf3-1 > CTR1_). At crossing of plants mutant lines nph4-1 × iar2-1 there is polymeric co-operation of genes NPH4 and IAR2 in the generation of F2.

Plant chimeras: The good, the bad, and the 'Bizzaria'.

Chimeras - organisms that are composed of cells of more than one genotype - captured the human imagination long before they were formally described and used in the laboratory. These organisms owe their namesake to a fire-breathing monster from Greek mythology that has the head of a lion, the body of a goat, and the tail of a serpent. The first description of a non-fictional chimera dates back to the middle of the seventeenth century when the Florentine gardener Pietro Nati discovered an adventitious shoot growing from the graft junction between sour orange (Citrus aurantium) and citron (Citrus medica). This perplexing chimera that grows with sectors phenotypically resembling each of the citrus progenitors inspired discussion and wonder from the scientific community and was fittingly named the 'Bizzaria'. Initially, the 'Bizzaria' was believed to be an asexual hybrid that formed from a cellular fusion between the grafted parents; however, in-depth cellular analyses carried out centuries later demonstrated that the 'Bizzaria', along with other chimeras, owe their unique sectored appearance to a conglomeration of cells from the two donors. Since this pivotal discovery at the turn of the twentieth century, chimeras have served both as tools and as unique biological phenomena that have contributed to our understanding of plant development at the cellular, tissue, and organismal level. Rapid advancements in genome sequencing technologies have enabled the establishment of new model species with novel morphological and developmental features that enable the generation of chimeric organisms. In this review, we show that genetic mosaic and chimera studies provide a technologically simple way to delve into the organismal, genetic, and genomic inner workings underlying the development of diverse model organisms. Moreover, we discuss the unique opportunity that chimeras present to explore universal principles governing intercellular communication and the coordination of organismal biology in a heterogenomic landscape.

Heritability and Reversibility of DNA Methylation Induced by in vitro Grafting between Brassica juncea and B. oleracea.

Grafting between tuber mustard and red cabbage produced a chimeric shoot apical meristem (SAM) of TTC, consisting of Layers I and II from Tuber mustard and Layer III from red Cabbage. Phenotypic variations, which mainly showed in leaf shape and SAM, were observed in selfed progenies GSn (GS = grafting-selfing, n = generations) of TTC. Here the heritability of phenotypic variation and its association with DNA methylation changes in GSn were investigated. Variation in leaf shape was found to be stably inherited to GS5, but SAM variation reverted over generations. Subsequent measurement of DNA methylation in GS1 revealed 5.29-6.59% methylation changes compared with tuber mustard (TTT), and 31.58% of these changes were stably transmitted to GS5, but the remainder reverted to the original status over generations, suggesting grafting-induced DNA methylation changes could be both heritable and reversible. Sequence analysis of differentially methylated fragments (DMFs) revealed methylation mainly changed within transposons and exon regions, which further affected the expression of genes, including flowering time- and gibberellin response-related genes. Interestingly, DMFs could match differentially expressed siRNA of GS1, GS3 and GS5, indicating that grafting-induced DNA methylation could be directed by siRNA changes. These results suggest grafting-induced DNA methylation may contribute to phenotypic variations induced by grafting.

Morphological Characteristics of Normal and Gynandromorphic Hyalomma asiaticum Schulze and Schlottke, 1930.

Gynandromorphic ticks are extremely rare, and often attract parasitologists' attention. During our examination of tick specimens, an engorged gynandromorph of Hyalomma asiaticum was noticed. This is the first record of gynandromorphic ticks from China. In this study, several important morphological structures of normal and gynandromorphic H. asiaticum were analyzed. Comparing to the normal H. asiaticum, the gynandromorphic specimen was a typical bipartite protogynander. Its right side showed normal female characteristics, whereas the left side had normal male traits. Different from other gynandromorphic ticks containing 1 anus, this tick reported here had 2 complete anuses, and the anus of the male part had a single adanal plate.

Morphological Characteristics of Normal and Gynandromorphic Hyalomma asiaticum Schulze and Schlottke, 1930

Gynandromorphic ticks are extremely rare, and often attract parasitologists' attention. During our examination of tick specimens, an engorged gynandromorph of Hyalomma asiaticum was noticed. This is the first record of gynandromorphic ticks from China. In this study, several important morphological structures of normal and gynandromorphic H. asiaticum were analyzed. Comparing to the normal H. asiaticum, the gynandromorphic specimen was a typical bipartite protogynander. Its right side showed normal female characteristics, whereas the left side had normal male traits. Different from other gynandromorphic ticks containing 1 anus, this tick reported here had 2 complete anuses, and the anus of the male part had a single adanal plate.

Early growth and development of reciprocal hybrids of the starry flounder Platichthys stellatus and stone flounder Kareius bicoloratus.

Larval growth and development of hybrid flounder were observed and compared with those of their parent species. The reciprocal hybrids of female starry flounder Platichthys stellatus and male stone flounder Kareius bicoloratus (hybrid Sb) and of female K. bicoloratus and male P. stellatus (hybrid Bs) both survived and grew to juveniles. Development was divided into nine stages (A-I). Many of the hybrids' traits were identical and intermediate to those of their parents. The position of the eye, however, was primarily sinistral in both hybrids (80% in Sb and 76% in Bs), a trait possessed by P. stellatus (80%) in the western Pacific Ocean. The daily growth rates of the larvae were similar. In the parent species, development was more rapid in P. stellatus than in K. bicoloratus whereas rate of development was intermediate in both Sb and Bs hybrids. The size at settlement [standard length (LS ) at stage H (mean ± s.d.)] was 9·82 ± 1·47 mm for the hybrid Sb and 9·99 ± 0·90 mm for the hybrid Bs, while the minimum age at metamorphosis (initial age at stage H) was 29 days after hatching (DAH) in both hybrids. In comparison, LS at settlement in parent species was 6·43 ± 0·25 mm for P. stellatus and 12·87 ± 1·29 mm for K. bicoloratus. Minimum age at metamorphosis for the parents was 23 DAH at stage G in P. stellatus and 34 DAH at stage H in K. bicoloratus. Thus, the timing of settlement of hybrids was different from that of their parent species. These traits may occur with high frequency in a natural habitat.

Evidence for the evolutionary origin of goldfish derived from the distant crossing of red crucian carp × common carp.

BACKGROUND: Distant hybridization can generate transgressive hybrid phenotypes that lead to the formation of new populations or species with increased genetic variation. In this study, we produced an experimental hybrid goldfish (EG) by distant crossing of red crucian carp (Carassius auratus) × common carp (Cyprinus carpio) followed by gynogenesis. RESULTS: We evaluated the phenotype, ploidy level, gonadal structure, and 5S rDNA of the EG. Diploid EG possessed a high level of genetic variation, which was stably inherited. In particular, the EG combined transgressive phenotypes, including a forked tail and shortened caudal peduncle, traits that are present in common goldfish. The EG and common goldfish share a number of morphological and genetic similarities. CONCLUSIONS: Using the EG, we provide new evidence that goldfish originated from hybridization of red crucian carp × common carp.

First flowering hybrid between autotrophic and mycoheterotrophic plant species: breakthrough in molecular biology of mycoheterotrophy.

Among land plants, which generally exhibit autotrophy through photosynthesis, about 880 species are mycoheterotrophs, dependent on mycorrhizal fungi for their carbon supply. Shifts in nutritional mode from autotrophy to mycoheterotrophy are usually accompanied by evolution of various combinations of characters related to structure and physiology, e.g., loss of foliage leaves and roots, reduction in seed size, degradation of plastid genome, and changes in mycorrhizal association and pollination strategy. However, the patterns and processes involved in such alterations are generally unknown. Hybrids between autotrophic and mycoheterotrophic plants may provide a breakthrough in molecular studies on the evolution of mycoheterotrophy. We have produced the first hybrid between autotrophic and mycoheterotrophic plant species using the orchid group Cymbidium. The autotrophic Cymbidium ensifolium subsp. haematodes and mycoheterotrophic C. macrorhizon were artificially pollinated, and aseptic germination of the hybrid seeds obtained was promoted by sonication. In vitro flowering was observed five years after seed sowing. Development of foliage leaves, an important character for photosynthesis, segregated in the first generation; that is, some individuals only developed scale leaves on the rhizome and flowering stems. However, all of the flowering plants formed roots, which is identical to the maternal parent.

Veterinary anatomy study sets

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Phenotypic variation across chromosomal hybrid zones of the common shrew (Sorex araneus) indicates reduced gene flow.

Sorex araneus, the Common shrew, is a species with more than 70 karyotypic races, many of which form parapatric hybrid zones, making it a model for studying chromosomal speciation. Hybrids between races have reduced fitness, but microsatellite markers have demonstrated considerable gene flow between them, calling into question whether the chromosomal barriers actually do contribute to genetic divergence. We studied phenotypic clines across two hybrid zones with especially complex heterozygotes. Hybrids between the Novosibirsk and Tomsk races produce chains of nine and three chromosomes at meiosis, and hybrids between the Moscow and Seliger races produce chains of eleven. Our goal was to determine whether phenotypes show evidence of reduced gene flow at hybrid zones. We used maximum likelihood to fit tanh cline models to geometric shape data and found that phenotypic clines in skulls and mandibles across these zones had similar centers and widths as chromosomal clines. The amount of phenotypic differentiation across the zones is greater than expected if it were dissipating due to unrestricted gene flow given the amount of time since contact, but it is less than expected to have accumulated from drift during allopatric separation in glacial refugia. Only if heritability is very low, Ne very high, and the time spent in allopatry very short, will the differences we observe be large enough to match the expectation of drift. Our results therefore suggest that phenotypic differentiation has been lost through gene flow since post-glacial secondary contact, but not as quickly as would be expected if there was free gene flow across the hybrid zones. The chromosomal tension zones are confirmed to be partial barriers that prevent differentiated races from becoming phenotypically homogenous.

Quantitative trait loci for morphometric body measurements of the hybrids of silver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis).

Quantitative trait loci (QTL) for 11 morphometric body measurements of the hybrids of silver (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) including body weight (BW), standard length (SL), body depth (BD), body thickness (BT), head length (HL), head depth (HD), length of ventral keel (LVK), length of pectoral fin (Lpec), length of pelvic fin (Lpel), length of caudal fin (Lcau) and space between pectoral and pelvic fins (SPP) were located on the sex average microsatellite linkage map constructed using the hybrids of a female bighead and a male silver carp, on which 15 microsatellites were newly mapped. One locus was found to be responsible for BW, LV K and SPP, respectively. As many as 6 loci were found to be responsible for HD. The variances of remaining traits were partitioned by different numbers of loci varying between 2 and 5. The variance explained each locus ranged from 9.1% to 23.8% of the total. The variance explained by all loci responsible for each measurement ranged from 17.7% to 75.1%. It was noted that multiple measurements were mapped on the same locus. For example, a region bounded by Hym435 and Hym145 was found to be responsible for all the measurements analyzed.

Synthesis of periclinal chimera in cassava.

We provide the first report on the synthesis of a very productive interspecific periclinal chimera of cassava, with large and edible roots. The epidermal tissue of the chimera was formed by the cultivated species Manihot esculenta (E), and the subepidermis and internal tissue were formed by the wild species, Manihot fortalezensis (F). We used cytogenetics and morphological analyses to determine the origins of all tissues. These results may offer potential for the development of new lines for crop improvement based on the use of chimera composed of different combinations of wild species and cultivars.

Genetic diversity and molecular characterization of several Heliconia species in Colombia.

Researchers have classified the Heliconia genus as a group of highly variable and diverse plants. Species and cultivars are visually differentiated primarily on the basis of the color and size of inflorescence bracts. At taxonomic level, flower type (parabolic, sigmoid, or erect) and size are taken into account. The vast morphological diversity of heliconias at intra-specific, intra-population, and varietal levels in central-west Colombia prompted the present study. We characterized the genetic variability of 67 genotypes of cultivated heliconias belonging to Heliconia caribaea Lamarck, H. bihai (L.) L., H. orthotricha L. Andersson, H. stricta Huber, H. wagneriana Petersen, and H. psittacorum L. f., as well as that of several interspecific hybrids such as H. psittacorum L. f. x H. spathocircinata Aristeguieta and H. caribaea Lamarck x H. bihai (L.) L. We also created an approximation to their phylogenetic analysis. Molecular analysis using amplified fragment length polymorphism (AFLP) markers revealed a total of 170 bands. Two large, well-defined groups resulted: the first grouped cultivars of the very closely related H. caribaea and H. bihai species with those of H. orthotricha and H. psittacorum, and the second grouped H. stricta and H. wagneriana cultivars. The lowest percentage of polymorphism was found in H. psittacorum (17.65%) and the highest was in H. stricta (55.88%). Using AFLP, phylogenetic analysis of the species studied revealed the monophyletic origin of the Heliconiaceae family, and identified the Heliconia subgenus as monophyletic while providing evidence of the polyphyletic origin of several representatives of the Stenochlamys subgenus.

Spatial genetic and morphologic structure of wolves and coyotes in relation to environmental heterogeneity in a Canis hybrid zone.

Eastern wolves have hybridized extensively with coyotes and gray wolves and are listed as a 'species of special concern' in Canada. However, a distinct population of eastern wolves has been identified in Algonquin Provincial Park (APP) in Ontario. Previous studies of the diverse Canis hybrid zone adjacent to APP have not linked genetic analysis with field data to investigate genotype-specific morphology or determine how resident animals of different ancestry are distributed across the landscape in relation to heterogeneous environmental conditions. Accordingly, we studied resident wolves and coyotes in and adjacent to APP to identify distinct Canis types, clarify the extent of the APP eastern wolf population beyond the park boundaries and investigate fine-scale spatial genetic structure and landscape-genotype associations in the hybrid zone. We documented three genetically distinct Canis types within the APP region that also differed morphologically, corresponding to putative gray wolves, eastern wolves and coyotes. We also documented a substantial number of hybrid individuals (36%) that were admixed between 2 or 3 of the Canis types. Breeding eastern wolves were less common outside of APP, but occurred in some unprotected areas where they were sympatric with a diverse combination of coyotes, gray wolves and hybrids. We found significant spatial genetic structure and identified a steep cline extending west from APP where the dominant genotype shifted abruptly from eastern wolves to coyotes and hybrids. The genotypic pattern to the south and northwest was a more complex mosaic of alternating genotypes. We modelled genetic ancestry in response to prey availability and human disturbance and found that individuals with greater wolf ancestry occupied areas of higher moose density and fewer roads. Our results clarify the structure of the Canis hybrid zone adjacent to APP and provide unique insight into environmental conditions influencing hybridization dynamics between wolves and coyotes.

Dissection of complex adult traits in a mouse synthetic population.

Finding the causative genetic variations that underlie complex adult traits is a significant experimental challenge. The unbiased search strategy of genome-wide association (GWAS) has been used extensively in recent human population studies. These efforts, however, typically find only a minor fraction of the genetic loci that are predicted to affect variation. As an experimental model for the analysis of adult polygenic traits, we measured a mouse population for multiple phenotypes and conducted a genome-wide search for effector loci. Complex adult phenotypes, related to body size and bone structure, were measured as component phenotypes, and each subphenotype was associated with a genomic spectrum of candidate effector loci. The strategy successfully detected several loci for the phenotypes, at genome-wide significance, using a single, modest-sized population (N = 505). The effector loci each explain 2%-10% of the measured trait variation and, taken together, the loci can account for over 25% of a trait's total population variation. A replicate population (N = 378) was used to confirm initially observed loci for one trait (femur length), and, when the two groups were merged, the combined population demonstrated increased power to detect loci. In contrast to human population studies, our mouse genome-wide searches find loci that individually explain a larger fraction of the observed variation. Also, the additive effects of our detected mouse loci more closely match the predicted genetic component of variation. The genetic loci discovered are logical candidates for components of the genetic networks having evolutionary conservation with human biology.

Morphological and molecular evidence for natural hybridization in sympatric population of Roscoea humeana and R. cautleoides (Zingiberaceae).

The sympatric occurrence of some species in Roscoea is very common, but little information is available on natural hybridization. However, some intermediate individuals were found on the sympatric population of Roscoea humeana and R. cautleoides at Ganhaizi population in northwestern Yunnan Province, China. We suspected that these intermediate individuals were the hybrids of R. humeana and R. cautleoides from the previous evidence, but could not confirm them. In this study, morphometric analysis was followed by examination of HAT-RAPD polymorphisms to determine the occurrence of natural hybridization between sympatric R. humeana and R. cautleoides. The results showed that most morphological characters of the putative hybrids were found to be intermediate between those of R. humeana and R. cautleoides. Meanwhile, molecular analysis confirmed that the morphological intermediates were derived from hybridization between the two species. From the analysis of the NewHybrids, the hybridization individuals were mainly F1s. These results indicated that interspecific hybridization between R. humeana and R. cautleoides indeed occurred in sympatric population.