scholarly journals Rapid adaptive evolution of scale-eating kinematics to a novel ecological niche

2019 ◽  
Author(s):  
Michelle E. St. John ◽  
Roi Holzman ◽  
Christopher H. Martin
Keyword(s):  
Surface Area ◽  
Ecological Niche ◽  
Prey Capture ◽  
F1 Hybrids ◽  
Obtuse Angle ◽  
F1 Hybrid ◽  
San Salvador ◽  
Lower Jaw ◽  
Foraging Preferences ◽  
Feeding Kinematics

AbstractThe origins of novel trophic specialization, in which organisms begin to exploit novel resources for the first time, may be explained by shifts in behavior such as foraging preferences or feeding kinematics. One way to investigate the behavioral mechanisms underlying ecological novelty is by comparing prey capture kinematics between groups. In this study, we investigated the contribution of kinematics to the origins of a novel ecological niche for scale-eating within a microendemic adaptive radiation of pupfishes on San Salvador Island, Bahamas. We compared prey capture kinematics across three species of pupfish while consuming shrimp and scales in the lab and found that scale-eating pupfish exhibited peak gape sizes that were twice as large as all other groups, but also attacked prey with a more obtuse angle between their lower jaw and suspensorium. We then investigated how this variation in feeding kinematics could explain scale-biting performance by measuring the surface area removed per strike from standardized gelatin cubes. We found that a combination of larger peak gape and more obtuse lower jaw and suspensorium angles resulted in 67% more surface area removed per strike, indicating that scale-eaters may reside on a performance optimum for scale-biting. We also measured feeding kinematics of F1 hybrids to test whether feeding performance could contribute to reproductive isolation between species and found that F1 hybrid kinematics and performance more closely resembled those of generalists, suggesting that they may have low fitness in the scale-eating niche. Ultimately, our results suggest that the evolution of strike kinematics in this radiation is an adaptation to the novel niche of scale-eating.

Quantitative analysis of feeding kinematics in dusky salamanders (Desmognathus)

1988 ◽  
Vol 66 (6) ◽  
pp. 1309-1317 ◽  
Author(s):  
John H. Larsen Jr. ◽  
John T. Beneski Jr.
Keyword(s):  
Quantitative Analysis ◽  
Prey Item ◽  
Prey Capture ◽  
Large Prey ◽  
Selective Force ◽  
Mandibular Symphysis ◽  
Lower Jaw ◽  
Feeding Kinematics

Gape formation by the dusky salamander (Desmognathus) involves both upper and lower jaws and occurs in a manner similar to that of other terrestrial salamanders. As Desmognathus opens its mouth, ventral rotation of the mandibles is restricted but not stopped by the atlas–mandibular ligaments; the lower jaw is not propelled anteriorly. Tongue protraction, well beyond the mandibular symphysis, is always a major component of prey capture by this genus. After the sticky tongue pad has made contact with the prey, the salamander's head surges forward and the pad is rapidly retracted with the prey item attached. Aided by a unique suite of characters the mouth then snaps shut with considerable force. Our study supports the premise that Desmognathus is no different from most, if not all, terrestrial salamanders in its employment of tongue projection as a major feature in prey capture. We argue that the primary selective force for the unique configuration of desmognathine cephalic structures was enhancement of the ability of these small salamanders to capture relatively large prey without an increase in the size of the head and body.

scholarly journals Ecological adaptation of an F1 hybrid cross of carnivorous and herbivorous Cyprinidae fishes

2020 ◽  
Author(s):  
Haoran Gu ◽  
You He ◽  
Sihong Deng ◽  
Xingheng He ◽  
Yi Wu ◽  
...  
Keyword(s):  
Ecological Niche ◽  
Ecological Factors ◽  
Food Resources ◽  
Ecological Adaptation ◽  
F1 Hybrids ◽  
Ecological Niches ◽  
Hybrid Speciation ◽  
Success Rates ◽  
F1 Hybrid ◽  
Species Isolation

Abstract Background Whether hybridization plays a positive or negative role in speciation remains a controversial issue to date. Genetic factors have been widely studied, but ecological factors also play an important role. Although studies on the ecological adaptation of hybrids between different niche parents have been widely reported, cases of extreme niche parental hybridization have not been documented, which may show more ecological phenomena in the fields of hybrid speciation and ecological species isolation. Results Taking Cyprinidae fish parents (Schizothorax wangchiachii and Percocypris pingi) with extreme ecological niches (herbivorous and carnivorous) and their F1 hybrids as research objects, fish, shrimp, blood worms and periphytic algae were selected as food correspond to four different ecological niches. Morphologically, most external and skeletal traits in the F1 hybrids were balanced between the parents, but digestive traits were closer to those of herbivorous parents. In terms of diet, the F1 hybrids weakly foraged for parental food resources, but can more effectively forage for intermediate food resources. In foraging abilities, the F1 hybrids showed low foraging enthusiasm and abilities for parent resources, although the former was the more important factor. Interestingly, the F1 hybrids showed high foraging enthusiasm and success rates when they first foraged for fish, but then they vomited fish debris as a result of mechanical difficulty in chewing rather than taste, and the reason was a contradiction between the genetic behaviours and intermediate morphology. This behaviour was harmful and was persistent in some individuals, representing a new mechanism in ecological species isolation. However, the F1 hybrids have also shown evidence of new ecological niche formation in favour of hybrid speciation by abandoning foraging parent resources and focusing more on foraging intermediate foods. Conclusions (1) Low foraging enthusiasm is an important reason for the fitness decrease of F1 hybrids to parent food. (2) The contradiction between genetic behavior and intermediate traits is reported for the first time. (3) F1 hybrids may form an intermediate ecological niche between parents proved experimentally.

scholarly journals Scaling the feeding mechanism of largemouth bass (Micropterus salmoides): kinematics of prey capture

1995 ◽  
Vol 198 (2) ◽  
pp. 419-433 ◽  
Author(s):  
B Richard ◽  
P Wainwright
Keyword(s):  
Body Size ◽  
Largemouth Bass ◽  
High Speed ◽  
Time Course ◽  
Prey Capture ◽  
Micropterus Salmoides ◽  
Feeding Mechanism ◽  
Functional Changes ◽  
Lower Jaw ◽  
Feeding Kinematics

We present the first analysis of scaling effects on prey capture kinematics of a feeding vertebrate. The scaling of feeding kinematics of largemouth bass (Micropterus salmoides) was investigated using high-speed video (200 fields s-1) to determine what functional changes occur in the feeding mechanism as a consequence of body size. A size series of ten bass ranging from 32 to 210 mm standard length was used for the study and ten feeding sequences from each individual were analyzed to quantify movements of the feeding apparatus during prey capture. Maximal linear and angular displacements of the strike scaled isometrically. The time course of the strike was longer in larger fish. Maximal velocities of displacement were more rapid in larger fish, but their scaling exponents indicated that the intrinsic rate of muscle shortening decreased with fish size. Morphological measurements of the lever arms of the lower jaw and of the two major muscles that drive the feeding mechanism were made to relate possible biomechanical changes in the feeding mechanism to the observed kinematic relationships. The lever arms of the lower jaw and the muscles scaled isometrically; hence, the relative slowing of movements with increasing body size cannot be attributed to changes in mechanical advantage with change in body size. The scaling of feeding kinematics in the largemouth bass is in accord with the scaling of rates of muscle contraction found in other lower vertebrates. These findings demonstrate that body size can have major effects on feeding kinematics and that future comparative studies of feeding kinematics should use empirical data on size effects in kinematic comparisons between taxa.

scholarly journals Sequencing an F1 hybrid of Silurus asotus and S. meridionalis enabled the assembly of high-quality parental genomes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Weitao Chen ◽  
Ming Zou ◽  
Yuefei Li ◽  
Shuli Zhu ◽  
Xinhui Li ◽  
...  
Keyword(s):  
De Novo ◽  
Parental Species ◽  
F1 Hybrids ◽  
Pelteobagrus Fulvidraco ◽  
F1 Hybrid ◽  
Short Reads ◽  
Final Assembly ◽  
Genome Complexity ◽  
Hybrid Genome ◽  
Silurus Asotus

AbstractGenome complexity such as heterozygosity may heavily influence its de novo assembly. Sequencing somatic cells of the F1 hybrids harboring two sets of genetic materials from both of the paternal and maternal species may avoid alleles discrimination during assembly. However, the feasibility of this strategy needs further assessments. We sequenced and assembled the genome of an F1 hybrid between Silurus asotus and S. meridionalis using the SequelII platform and Hi-C scaffolding technologies. More than 300 Gb raw data were generated, and the final assembly obtained 2344 scaffolds composed of 3017 contigs. The N50 length of scaffolds and contigs was 28.55 Mb and 7.49 Mb, respectively. Based on the mapping results of short reads generated for the paternal and maternal species, each of the 29 chromosomes originating from S. asotus and S. meridionalis was recognized. We recovered nearly 94% and 96% of the total length of S. asotus and S. meridionalis. BUSCO assessments and mapping analyses suggested that both genomes had high completeness and accuracy. Further analyses demonstrated the high collinearity between S. asotus, S. meridionalis, and the related Pelteobagrus fulvidraco. Comparison of the two genomes with that assembled only using the short reads from non-hybrid parental species detected a small portion of sequences that may be incorrectly assigned to the different species. We supposed that at least part of these situations may have resulted from mitotic recombination. The strategy of sequencing the F1 hybrid genome can recover the vast majority of the parental genomes and may improve the assembly of complex genomes.

scholarly journals Fitness of F1 hybrids between 10 maternal wild soybean populations and transgenic soybean

2021 ◽  
Author(s):  
Jin Yue Liu ◽  
Ze Wen Sheng ◽  
Yu Qi Hu ◽  
Qi Liu ◽  
Sheng Qiang ◽  
...  
Keyword(s):  
Seed Weight ◽  
Wild Soybean ◽  
F1 Hybrids ◽  
Weed Competition ◽  
Transgenic Soybean ◽  
Wild Progenitor ◽  
F1 Hybrid ◽  
Dry Biomass ◽  
100 Seed Weight ◽  
Pod Number

AbstractThe releasing of transgenic soybeans (Glycine max (L.) Merr.) into farming systems raises concerns that transgenes might escape from the soybeans via pollen into their endemic wild relatives, the wild soybean (Glycine soja Sieb. et Zucc.). The fitness of F1 hybrids obtained from 10 wild soybean populations collected from China and transgenic glyphosate-resistant soybean was measured without weed competition, as well as one JLBC-1 F1 hybrid under weed competition. All crossed seeds emerged at a lower rate from 13.33–63.33%. Compared with those of their wild progenitors, most F1 hybrids were shorter, smaller, and with decreased aboveground dry biomass, pod number, and 100-seed weight. All F1 hybrids had lower pollen viability and filled seeds per plant. Finally, the composite fitness of nine F1 hybrids was significantly lower. One exceptional F1 hybrid was IMBT F1, in which the composite fitness was 1.28, which was similar to that of its wild progenitor due to the similarities in pod number, increased aboveground dry biomass, and 100-seed weight. Under weed competition, plant height, aboveground dry biomass, pod number per plant, filled seed number per plant, and 100-seed weight of JLBC-1 F1 were lower than those of the wild progenitor JLBC-1. JLBC-1 F1 hybrids produced 60 filled seeds per plant. Therefore, F1 hybrids could emerge and produce offspring. Thus, effective measures should be taken to prevent gene flow from transgenic soybean to wild soybean to avoid the production F1 hybrids when releasing transgenic soybean in fields in the future.

scholarly journals Ecological divergence in sympatry causes gene misregulation in hybrids

2019 ◽  
Author(s):  
Joseph A. McGirr ◽  
Christopher H. Martin
Keyword(s):  
Gene Expression ◽  
Reproductive Isolation ◽  
Differentially Expressed ◽  
F1 Hybrids ◽  
Adaptive Divergence ◽  
Lower Hybrid ◽  
Hybrid Fitness ◽  
Hybrid Gene ◽  
San Salvador ◽  
Ecological Selection

AbstractEcological speciation occurs when reproductive isolation evolves as a byproduct of adaptive divergence between populations. However, it is unknown whether divergent ecological selection on gene regulation can directly cause reproductive isolation. Selection favoring regulatory divergence between species could result in gene misregulation in F1 hybrids and ultimately lower hybrid fitness. We combined 58 resequenced genomes with 124 transcriptomes to test this hypothesis in a young, sympatric radiation of Cyprinodon pupfishes endemic to San Salvador Island, Bahamas, which consists of a dietary generalist and two novel trophic specialists – a molluscivore and a scale-eater. We found more differential gene expression between closely related sympatric specialists than between allopatric generalist populations separated by 1000 km. Intriguingly, 9.6% of genes that were differentially expressed between sympatric species were also misregulated in their F1 hybrids. Consistent with divergent ecological selection causing misregulation, a subset of these genes were in highly differentiated genomic regions and enriched for functions important for trophic specialization, including head, muscle, and brain development. These regions also included genes that showed evidence of hard selective sweeps and were significantly associated with oral jaw length – the most rapidly diversifying skeletal trait in this radiation. Our results indicate that divergent ecological selection in sympatry can cause hybrid gene misregulation which may act as a primary reproductive barrier between nascent species.SignificanceIt is unknown whether the same genes that regulate ecological traits can simultaneously contribute to reproductive barriers between species. We measured gene expression in two trophic specialist species of Cyprinodon pupfishes that rapidly diverged from a generalist ancestor. We found genes differentially expressed between species that also showed extreme expression levels in their hybrid offspring. Many of these genes showed signs of selection and have putative effects on the development of traits that are important for ecological specialization. This suggests that genetic variants contributing to adaptive trait divergence between parental species negatively interact to cause hybrid gene misregulation, potentially producing unfit hybrids. Such loci may be important barriers to gene flow during the early stages of speciation, even in sympatry.

scholarly journals Reciprocal F1 hybrids of two inbred mouse strains reveal parent-of-origin and perinatal diet effects on behavior and expression

2018 ◽  
Author(s):  
Daniel Oreperk ◽  
Sarah A Schoenrock ◽  
Rachel McMullan ◽  
Robin Ervin ◽  
Joseph Farrington ◽  
...  
Keyword(s):  
Complex Traits ◽  
Detection System ◽  
Inbred Mouse ◽  
F1 Hybrids ◽  
Hybrid Population ◽  
Psychiatric Disease ◽  
Mouse Strains ◽  
Imprinted Genes ◽  
F1 Hybrid ◽  
Parent Of Origin

ABSTRACTParent-of-origin effects (POEs) in mammals typically arise from maternal effects or from imprinting. Mutations in imprinted genes have been associated with psychiatric disorders, as well as with changes in a handful of animal behaviors. Nonetheless, POEs on complex traits such as behavior remain largely uncharacterized. Furthermore, although perinatal environmental exposures, such as nutrient deficiency, are known to modify both behavior and epigenetic effects generally, the architecture of environment-by-POE is almost completely unexplored. To study POE and environment-by-POE, we employ a relatively neglected but maximally powerful POE-detection system: a reciprocal F1 hybrid population. We exposed female NOD/ShiLtJxC57Bl/6J and C57Bl/6JxNOD/ShiLtJ mice, in utero, to one of four different diets, then after weaning recorded their whole-brain gene expression, as well as a set of behaviors that model psychiatric disease. Microarray expression data revealed an imprinting-enriched set of over a dozen genes subject to POE; the POE on the most significantly affected gene, Carmil1 (a.k.a. Lrrc16a), was validated using qPCR in the same and in a new set of mice. Several behaviors, especially locomotor behaviors, also showed POE. Interestingly, Bayesian mediation analysis suggests Carmil1 expression suppresses behavioral POE, and Airn suppresses POE on Carmil1 expression. A significant diet-by-POE was observed on one behavior, one imprinted gene, and over a dozen non-imprinted genes. Beyond our particular results, our study demonstrates a reciprocal F1 hybrid framework for studying POE and environment-by-POE on behavior.

scholarly journals Evaluation of onion samples (Allium cepa L.) of various origins in the foothill zone of the North Caucasus and creation of source material fo

2021 ◽  
pp. 58-64
Author(s):  
I. S. Mastyaev ◽  
A. F. Agafonov ◽  
L. V. Krivenkov
Keyword(s):  
Climatic Conditions ◽  
Source Material ◽  
Biologically Active ◽  
F1 Hybrids ◽  
North Caucasus ◽  
F1 Hybrid ◽  
The North ◽  
Long Term Storage ◽  
Economically Valuable Traits ◽  
High Yields

Relevance. The success of breeding work is largely determined by the source material, the search and creation of which for target breeding begins with the collection and study of collectible samples for the alignment of morphological features; for the precocity and amity of maturation; for the keeping quality and transportability of bulbs; for the quality of vegetable products (high content of biologically active substances and antioxidants); for resistance to biotic and abiotic stressors of a specific growing zone.Materials and methods. On the basis of the North Caucasus branch FSBSI FSVC, 90 samples of spring onions from 26 countries of the world were evaluated in the number nursery for the period from 2017 to 2019, 71 of them were varieties and 19 were F1 hybrids. In a hybrid nursery, 25 hybrid combinations obtained from FSBSI FSVC (VNIISSOK) were evaluated. The laying and placement of experiments, agricultural techniques of cultivation, accounting and evaluation of economically valuable traits, biochemical analyses were carried out according to generally accepted methods. The standards are the new Primo and Ampex varieties of the selection of the FSBSI FSVC and the Italian F1 hybrid Ranko, which were placed every 10 collection samples.Results.According to the results of the assessment, among the studied F1 varieties and hybrids, sources of economically valuable traits such as yield (20-27 t/ha), precocity (80-90 days), preservation (more than 85%) when laid for long-term storage up to 7 months, purple, white and pink color of bulbs, as well as sources of long-shaped bulbs were identified. The greatest interest for breeding for yield is represented by 9 promising varieties and 9 F1 hybrids of onions of various origins, as well as 4 hybrid combinations that were distinguished by high yields, the yield of marketable products and the mass of marketable bulbs. These samples are recommended for use in the breeding process as sources for the creation of new varieties and hybrids with high yields for the agro-climatic conditions of the foothill zone of the North Caucasus.r breeding

The roles of pyruvate, lactate and glucose during preimplantation development of embryos from F1 hybrid mice in vitro

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 99-105 ◽  
Author(s):  
J.J. Brown ◽  
D.G. Whittingham
Keyword(s):  
Inbred Mouse ◽  
Blastocyst Stage ◽  
Preimplantation Development ◽  
F1 Hybrids ◽  
Mouse Strains ◽  
F1 Hybrid ◽  
Morula Stage ◽  
Lactate And Pyruvate ◽  
Hybrid Mice

Embryos of certain inbred mouse strains, and their F1 hybrids, are able to develop from the 1-cell to blastocyst stage in simple chemically defined media containing lactate (L), pyruvate (P) and glucose (G). The individual roles of these substrates in supporting complete preimplantation development in vitro was examined with 1-cell F2 embryos from B6CBF1 hybrid mice. Embryos collected between 26 and 27 h post hCG were cultured in medium containing L, P, LP or LPG. After 50 h in culture, the proportions developing to the morula stage were 1%, 83%, 94% and 100%, respectively. In combination, lactate and pyruvate appeared to act synergistically and both the rate and level of development to the morula stage were unaffected by the absence of glucose. After a further 46 h in culture, only the embryos grown in the presence of glucose developed into blastocysts. In LP medium, embryos arrested at the compacted morula stage late on day 3 of development. As culture continued in the absence of glucose, embryos decompacted (approximately 82 h post hCG) and subsequently degenerated. Exposure to medium containing glucose for the first, second or third 24 h period in culture was sufficient to support the morula-to-blastocyst transition. Glucose still supported this transition when embryos were transferred to LPG medium 3 h after the completion of compaction (76 h post hCG), but was ineffective 6 h later (82 h post hCG) once decompaction had commenced. We conclude that lactate and pyruvate together are able to support normal development of 1-cell F2 embryos to the morula stage in vitro, but that glucose is an essential component of the culture medium for development to the blastocyst stage.

scholarly journals Brief Report: Graft-Versus-Host Reaction in F1 Hybrid Mice Injected with Pre-Immunized Parental Thymus Cells

Blood ◽  
1964 ◽  
Vol 24 (6) ◽  
pp. 770-774 ◽  
Author(s):  
LUCIANO FIORE-DONATI ◽  
LUIGI CHIECO-BIANCHI ◽  
GIUSEPPE DE BENEDICTIS ◽  
GIUSEPPE TRIDENTE
Keyword(s):  
Lymphoid Cells ◽  
The Other ◽  
F1 Hybrids ◽  
Graft Versus Host Reaction ◽  
Host Reaction ◽  
F1 Hybrid ◽  
Graft Versus Host ◽  
Immunologic Activity ◽  
Thymus Cells ◽  
Hybrid Mice

Abstract Dissociated thymus cells are capable of initiating graft-versus-host reaction in (C3Hf/Gs x DBA/2)F1 hybrids only when derived from parental donors previously sensitized against the antigens of the other parental strain. The lower immunologic activity of thymus cells as compared with other lymphoid cells is presumably due to quantitative rather than qualitative differences in immunologically competent cells.

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