The conserved fraction of repetitive sequences in the human and mammalian genome in health, in pathology, and for long-term mutagenic exposure

1994 ◽  
Vol 117 (1) ◽  
pp. 89-92
Author(s):  
A. I. Potapenko ◽  
G. A. Khudolii ◽  
A. P. Akif'ev
Keyword(s):  
Repetitive Sequences ◽  
Mammalian Genome

Shared sequence variants of Mus spretus LINE-1 elements tracing dispersal to within the last 1 million years.

Genetics ◽  
1994 ◽  
Vol 137 (2) ◽  
pp. 565-572
Author(s):  
N C Casavant ◽  
S C Hardies
Keyword(s):  
Repetitive Sequences ◽  
Mammalian Genome ◽  
Mus Domesticus ◽  
Sequence Variants ◽  
Mus Spretus ◽  
Specific Sequence

Abstract LINE-1 repetitive sequences contain a record of an evolving population of transposons within the mammalian genome. Of the 100,000 copies of LINE-1 sequences per genome there are many shared sequence variants representing changes occurring within the propagating LINE-1 elements themselves, rather than changes that occur during retrotransposition or after an element inserts in the genome. These shared sequence variants define families of LINE-1 elements which have spread within specific periods of time. We have been interested in studying events in LINE-1 evolution since the speciation of Mus spretus and Mus domesticus approximately 3 million years (Myr) ago. To do this, we have collected LINE-1 sequences that have shared sequence variants specific to M. spretus. The sampled LINE-1 elements were sequenced at their extreme 3' ends, where the density of sequence variants is highest. The new sequences define six new M. spretus-specific sequence variants. Of these, we have found one that could be used to screen for LINE-1 elements arising in the last 1 Myr, which we argue is a critical sample for understanding the dynamics of LINE-1 propagation.

scholarly journals Development and Characterisation of Irap Markers From Expressed Retrotransposon-like sequences in Pinus sylvestris L.

2014 ◽  
Vol 67 (6) ◽  
pp. 485-492 ◽  
Author(s):  
Angelika Voronova ◽  
Dainis Ruņģis
Keyword(s):  
Genetic Diversity ◽  
Pinus Sylvestris ◽  
Scots Pine ◽  
Repetitive Sequences ◽  
Gene Families ◽  
Considerable Proportion ◽  
Long Terminal Repeats ◽  
Multiple Gene ◽  
Plant Genomes

AbstractConifer genomes are large and stably diploid, in contrast to angiosperms, which are more variable both in genome size and ploidy. Conifer genomes are characterised by multiple gene families and pseudogenes, contain large inter-gene regions and a considerable proportion of repetitive sequences. All members of plant retrotransposon orders have been identified in gymnosperm genomes, however active elements have not been described. Investigation of transposable elements in Scots pine (Pinus sylvestris L.) could offer insights into transposon-mediated reorganisation under stress conditions in complex and ancient plant genomes. Nine Pinus sylvestris specific markers were developed to hypothetical long terminal repeats (LTRs) from differentially expressed retrotransposon-like fragments after heat stress and insect damage. Genetic diversity of 150 trees from a naturally regenerated pine stand was investigated using the IRAP method. The developed markers revealed high levels of genetic diversity and were able to distinguish subpopulations growing in long-term differential environmental conditions. Somaclonal variation was also investigated using these markers and polymorphic fragments were identified between ramets of Scots pine clones growing in two different plantations, possibly indicating evidence of recent transposition events. Sequencing of the polymorphic fragments identified two groups of sequences containing LTR sequences of an unknown retrotransposon with homology to the LTRs of the Copia-17-PAb-I element.

scholarly journals Root Endophytes and Ginkgo biloba Are Likely to Share and Compensate Secondary Metabolic Processes, and Potentially Exchange Genetic Information by LTR-RTs

2021 ◽  
Vol 12 ◽  
Author(s):  
Kai Zou ◽  
Xueduan Liu ◽  
Qi Hu ◽  
Du Zhang ◽  
Shaodong Fu ◽  
...  
Keyword(s):  
Ginkgo Biloba ◽  
Genetic Information ◽  
Repetitive Sequences ◽  
Isoquinoline Alkaloid ◽  
Mutual Transformation ◽  
Alkaloid Biosynthesis ◽  
High Similarity ◽  
Gene Profiles ◽  
Bacteria And Fungi

Ginkgo biloba is a pharmaceutical resource for terpenes and flavonoids. However, few insights discussed endophytes’ role in Ginkgo, and whether genetic exchange happens between Ginkgo and endophytes remains unclear. Herein, functional gene profiles and repetitive sequences were analyzed to focus on these issues. A total of 25 endophyte strains were isolated from the Ginkgo root and distributed in 16 genera of 6 phyla. Significant morphological diversities lead to the diversity in the COG functional classification. KEGG mapping revealed that endophytic bacteria and fungi potentially synthesize chalcone, while endophytic fungi might also promote flavonoid derivatization. Both bacteria and fungi may facilitate the lignin synthesis. Aspergillus sp. Gbtc_1 exhibited the feasibility of regulating alcohols to lignans. Although Ginkgo and the endophytes have not observed the critical levopimaradiene synthase in ginkgolides synthesis, the upstream pathways of terpenoid precursors are likely intact. The MVK genes in Ginkgo may have alternative non-homologous copies or be compensated by endophytes in long-term symbiosis. Cellulomonas sp. Gbtc_1 became the only bacteria to harbor both MEP and MVA pathways. Endophytes may perform the mutual transformation of IPP and DMAPP in the root. Ginkgo and bacteria may lead to the synthesis and derivatization of the carotenoid pathway. The isoquinoline alkaloid biosynthesis seemed lost in the Ginkgo root community, but L-dopa is more probably converted into dopamine as an essential signal-transduction substance. So, endophytes may participate in the secondary metabolism of the Ginkgo in a shared or complementary manner. Moreover, a few endophytic sequences predicted as Ty3/Gypsy and Ty1/Copia superfamilies exhibited extremely high similarity to those of Ginkgo. CDSs in such endophytic LTR-RT sequences were also highly homologous to one Ginkgo CDS. Therefore, LTR-RTs may be a rare unit flowing between the Ginkgo host and endophytes to exchange genetic information. Collectively, this research effectively expanded the insight on the symbiotic relationship between the Ginkgo host and the endophytes in the root.

Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis
Keyword(s):  
Mental Health ◽  
Mental Disease ◽  
Brain Disorders ◽  
Social Stressors ◽  
Labor Education ◽  
Mental Diseases ◽  
Long Term Follow Up ◽  
Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

Brief summary of Kleť photographic search programme for minor planets

1999 ◽  
Vol 173 ◽  
pp. 189-192
Author(s):  
J. Tichá ◽  
M. Tichý ◽  
Z. Moravec
Keyword(s):  
Ccd Camera ◽  
Minor Planet ◽  
Minor Planets ◽  
Main Belt

AbstractA long-term photographic search programme for minor planets was begun at the Kleť Observatory at the end of seventies using a 0.63-m Maksutov telescope, but with insufficient respect for long-arc follow-up astrometry. More than two thousand provisional designations were given to new Kleť discoveries. Since 1993 targeted follow-up astrometry of Kleť candidates has been performed with a 0.57-m reflector equipped with a CCD camera, and reliable orbits for many previous Kleť discoveries have been determined. The photographic programme results in more than 350 numbered minor planets credited to Kleť, one of the world's most prolific discovery sites. Nearly 50 per cent of them were numbered as a consequence of CCD follow-up observations since 1994.This brief summary describes the results of this Kleť photographic minor planet survey between 1977 and 1996. The majority of the Kleť photographic discoveries are main belt asteroids, but two Amor type asteroids and one Trojan have been found.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

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