scholarly journals Fine Scale Genomic Signals of Admixture and Alien Introgression among Asian Rice Landraces

2019 ◽  
Vol 11 (5) ◽  
pp. 1358-1373 ◽  
Author(s):  
João D Santos ◽  
Dmytro Chebotarov ◽  
Kenneth L McNally ◽  
Jérôme Bartholomé ◽  
Gaëtan Droc ◽  
...  
Keyword(s):  
Fine Scale ◽  
Alien Introgression ◽  
Asian Rice ◽  
Rice Landraces ◽  
Genomic Signals

scholarly journals Ethical and Policy Concerns pertaining to Rice Landraces in Asia

1970 ◽  
Vol 2 (1) ◽  
pp. 7-12
Author(s):  
Abhik Gupta
Keyword(s):  
Southern China ◽  
Oryza Sativa L ◽  
Indian Subcontinent ◽  
Life Forms ◽  
Calorie Intake ◽  
Pests And Diseases ◽  
Asian Rice ◽  
Rice Landraces ◽  
Farmer Selection ◽  
Traditional Landraces

Domestication of rice (Oryza sativa L.) from the wild species O. rufipogon and O. nivara by Neolithic Asian farmers more than 10,000 years ago represents one of the most important events in human history, as this crop is the major staple food of over one-third of the world’s population, meeting around 20 % of the global calorie intake. The Asian rice, O. sativa, which is grown worldwide, has three major “variety groups” or subspecies: indica varieties of the Indian subcontinent; tropical japonica or javanica varieties very common in southeast Asia and southern China; and temperate japonica varieties predominantly cultivated in northeastern Asia. Furthermore, cultivation and farmer selection over a long period of time have given rise to over 120,000 varieties or farmer’s landraces of rice. These include glutinous and non-glutinous landraces, aromatic landraces; those taking different times to mature; with different levels of tolerance to abiotic stresses like cold, drought, submergence and salinity; and even differing in their resistance to pests and diseases. However, a few hundred “high-yielding” “improved” varieties have largely replaced these traditional landraces, with the latter finding their place of preservation in the rice germplasm banks. While it is true that various genes of the traditional landraces have been incorporated into many modern varieties, questions arise as to the ethical propriety of banishing ‘live’ and ‘flourishing’ life forms that are also integrally linked to the culture of many communities, to a ‘synthetic, and overtly utilitarian existence. The present paper aims to discuss these issues in the light of ethical principles as well as policies pertaining to traditional knowledge and practices.DOI: http://dx.doi.org/10.3329/bioethics.v2i1.9811  Bangladesh Journal of Bioethics 2011; 2(1): 7-12

scholarly journals Resequencing of 672 Native Rice Accessions to Explore Genetic Diversity and Trait Associations in Vietnam

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Janet Higgins ◽  
Bruno Santos ◽  
Tran Dang Khanh ◽  
Khuat Huu Trung ◽  
Tran Duy Duong ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Heading Date ◽  
Cultivated Rice ◽  
Rice Varieties ◽  
Asian Rice ◽  
Rice Landraces ◽  
Shared Ancestry ◽  
Production Areas ◽  
Rice Diversity ◽  
Trait Associations

Abstract Background Vietnam possesses a vast diversity of rice landraces due to its geographical situation, latitudinal range, and a variety of ecosystems. This genetic diversity constitutes a highly valuable resource at a time when the highest rice production areas in the low-lying Mekong and Red River Deltas are enduring increasing threats from climate changes, particularly in rainfall and temperature patterns. Results We analysed 672 Vietnamese rice genomes, 616 newly sequenced, that encompass the range of rice varieties grown in the diverse ecosystems found throughout Vietnam. We described four Japonica and five Indica subpopulations within Vietnam likely adapted to the region of origin. We compared the population structure and genetic diversity of these Vietnamese rice genomes to the 3000 genomes of Asian cultivated rice. The named Indica-5 (I5) subpopulation was expanded in Vietnam and contained lowland Indica accessions, which had very low shared ancestry with accessions from any other subpopulation and were previously overlooked as admixtures. We scored phenotypic measurements for nineteen traits and identified 453 unique genotype-phenotype significant associations comprising twenty-one QTLs (quantitative trait loci). The strongest associations were observed for grain size traits, while weaker associations were observed for a range of characteristics, including panicle length, heading date and leaf width. Conclusions We showed how the rice diversity within Vietnam relates to the wider Asian rice diversity by using a number of approaches to provide a clear picture of the novel diversity present within Vietnam, mainly around the Indica-5 subpopulation. Our results highlight differences in genome composition and trait associations among traditional Vietnamese rice accessions, which are likely the product of adaption to multiple environmental conditions and regional preferences in a very diverse country. Our results highlighted traits and their associated genomic regions that are a potential source of novel loci and alleles to breed a new generation of low input sustainable and climate resilient rice.

High Resolution Stereography of Complementary Freeze-Fracture Replicas Reveals the Presence of Depressions Opposite Membrane Associated Particles of Split Membranes

1971 ◽  
Vol 29 ◽  
pp. 442-443
Author(s):  
Russell L. Steere
Keyword(s):  
High Resolution ◽  
Cardiac Muscle ◽  
Electron Micrographs ◽  
Chromic Acid ◽  
Freeze Fracture ◽  
Distilled Water ◽  
Fine Scale ◽  
Acid Cleaning ◽  
Cleaning Solution

Complementary replicas have revealed the fact that the two common faces observed in electron micrographs of freeze-fracture and freeze-etch specimens are complementary to each other and are thus the new faces of a split membrane rather than the original inner and outer surfaces (1, 2 and personal observations). The big question raised by published electron micrographs is why do we not see depressions in the complementary face opposite membrane-associated particles? Reports have appeared indicating that some depressions do appear but complementarity on such a fine scale has yet to be shown.Dog cardiac muscle was perfused with glutaraldehyde, washed in distilled water, then transferred to 30% glycerol (material furnished by Dr. Joaquim Sommer, Duke Univ., and VA Hospital, Durham, N.C.). Small strips were freeze-fractured in a Denton Vacuum DFE-2 Freeze-Etch Unit with complementary replica tooling. Replicas were cleaned in chromic acid cleaning solution, then washed in 4 changes of distilled water and mounted on opposite sides of the center wire of a Formvar-coated grid.

Fine-scale taxonomic and temporal variability in the energy density of invertebrate prey of juvenile Chinook salmon Oncorhynchus tshawytscha

2020 ◽  
Vol 655 ◽  
pp. 185-198
Author(s):  
J Weil ◽  
WDP Duguid ◽  
F Juanes
Keyword(s):  
Energy Density ◽  
Chinook Salmon ◽  
Temporal Variability ◽  
Energy Content ◽  
Single Point ◽  
Single Species ◽  
Fine Scale ◽  
Temporal Differences ◽  
Juvenile Chinook Salmon ◽  
Juvenile Chinook

Variation in the energy content of prey can drive the diet choice, growth and ultimate survival of consumers. In Pacific salmon species, obtaining sufficient energy for rapid growth during early marine residence is hypothesized to reduce the risk of size-selective mortality. In order to determine the energetic benefit of feeding choices for individuals, accurate estimates of energy density (ED) across prey groups are required. Frequently, a single species is assumed to be representative of a larger taxonomic group or related species. Further, single-point estimates are often assumed to be representative of a group across seasons, despite temporal variability. To test the validity of these practices, we sampled zooplankton prey of juvenile Chinook salmon to investigate fine-scale taxonomic and temporal differences in ED. Using a recently developed model to estimate the ED of organisms using percent ash-free dry weight, we compared energy content of several groups that are typically grouped together in growth studies. Decapod megalopae were more energy rich than zoeae and showed family-level variability in ED. Amphipods showed significant species-level variability in ED. Temporal differences were observed, but patterns were not consistent among groups. Bioenergetic model simulations showed that growth rate of juvenile Chinook salmon was almost identical when prey ED values were calculated on a fine scale or on a taxon-averaged coarse scale. However, single-species representative calculations of prey ED yielded highly variable output in growth depending on the representative species used. These results suggest that the latter approach may yield significantly biased results.

Fine-scale habitat partitioning facilitates sympatry between two octopus species in a shallow Florida lagoon

2019 ◽  
Vol 609 ◽  
pp. 151-161 ◽  
Author(s):  
CO Bennice ◽  
AP Rayburn ◽  
WR Brooks ◽  
RT Hanlon
Keyword(s):  
Habitat Partitioning ◽  
Fine Scale

Small pelagic fish responses to fine-scale oceanographic conditions: implications for the endangered African penguin

2017 ◽  
Vol 569 ◽  
pp. 187-203 ◽  
Author(s):  
AM McInnes ◽  
PG Ryan ◽  
M Lacerda ◽  
J Deshayes ◽  
WS Goschen ◽  
...  
Keyword(s):  
Pelagic Fish ◽  
Fine Scale ◽  
Small Pelagic Fish ◽  
African Penguin ◽  
Oceanographic Conditions
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