scholarly journals Chromosomal Differentiation of Deschampsia (Poaceae) Based on Four Satellite DNA Families

2021 ◽  
Vol 12 ◽  
Author(s):  
María Laura González ◽  
Jorge Oscar Chiapella ◽  
Juan Domingo Urdampilleta
Keyword(s):  
Distribution Pattern ◽  
Satellite Dna ◽  
Random Distribution ◽  
Chromosomal Location ◽  
Genomic Analysis ◽  
Interspecific Variation ◽  
General Distribution ◽  
Repeat Sequences ◽  
Tandem Repeat Sequences ◽  
Chromosomal Differentiation

Diverse families of satellite DNA (satDNA) were detected in heterochromatin regions of Deschampsia. This kind of repetitive DNA consists of tandem repeat sequences forming big arrays in genomes, and can contribute to lineages differentiation. The differentiation between types of satDNA is related to their sequence identity, the size and number of monomers forming the array, and their chromosomal location. In this work, four families of satDNA (D2, D3, D12, D13), previously isolated by genomic analysis, were studied on chromosomal preparations of 12 species of Deschampsia (D. airiformis, D. antarctica, D. cespitosa, D. cordillerarum, D. elongata, D. kingii, D. laxa, D. mendocina, D. parvula, D. patula, D. venustula, and Deschampsia sp) and one of Deyeuxia (D. eminens). Despite the number of satDNA loci showing interspecific variation, the general distribution pattern of each satDNA family is maintained. The four satDNA families are AT-rich and associated with DAPI + heterochromatin regions. D2, D3, and D12 have mainly subterminal distribution, while D13 is distributed in intercalary regions. Such conservation of satDNA patterns suggests a not random distribution in genomes, where the variation between species is mainly associated with the array size and the loci number. The presence of satDNA in all species studied suggests a low genetic differentiation of sequences. On the other hand, the variation of the distribution pattern of satDNA has no clear association with phylogeny. This may be related to high differential amplification and contraction of sequences between lineages, as explained by the library model.

Differences and similarities between various tandem repeat sequences: Minisatellites and microsatellites

Biochimie ◽  
1997 ◽  
Vol 79 (9-10) ◽  
pp. 577-586 ◽  
Author(s):  
H. Debrauwere ◽  
C.G. Gendrel ◽  
S. Lechat ◽  
M. Dutreix
Keyword(s):  
Tandem Repeat ◽  
Repeat Sequences ◽  
Tandem Repeat Sequences

Karyotypes and Distribution of Tandem Repeat Sequences in Brassica nigra Determined by Fluorescence in situ Hybridization

2017 ◽  
Vol 152 (3) ◽  
pp. 158-165 ◽  
Author(s):  
Gui-xiang Wang ◽  
Qun-yan He ◽  
Jiri Macas ◽  
Petr Novák ◽  
Pavel Neumann ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Fluorescence Intensity ◽  
Tandem Repeat ◽  
Brassica Nigra ◽  
Metaphase Chromosomes ◽  
Repeat Sequences ◽  
Tandem Repeat Sequences ◽  
Black Mustard

Whole-genome shotgun reads were analyzed to determine the repeat sequence composition in the genome of black mustard, Brassica nigra (L.) Koch. The analysis showed that satellite DNA sequences are very abundant in the black mustard genome. The distribution pattern of 7 new tandem repeats (BnSAT13, BnSAT28, BnSAT68, BnSAT76, BnSAT114, BnSAT180, and BnSAT200) on black mustard chromosomes was visualized using fluorescence in situ hybridization (FISH). The FISH signals of BnSAT13 and BnSAT76 provided useful cytogenetic markers; their position and fluorescence intensity allowed for unambiguous identification of all 8 somatic metaphase chromosomes. A karyotype showing the location and fluorescence intensity of these tandem repeat sequences together with the position of rDNAs and centromeric retrotransposons of Brassica (CRB) was constructed. The establishment of the FISH-based karyotype in B. nigra provides valuable information that can be used in detailed analyses of B. nigra accessions and derived allopolyploid Brassica species containing the B genome.

Cloning, characterization and chromosomal location of a satellite DNA from the Pacific oyster, Crassostrea gigas

Gene ◽  
1996 ◽  
Vol 168 (2) ◽  
pp. 205-209 ◽  
Author(s):  
Catherine Clabby ◽  
Usha Goswami ◽  
Fiona Flavin ◽  
Noel P. Wilkins ◽  
James A. Houghton ◽  
...  
Keyword(s):  
Crassostrea Gigas ◽  
Satellite Dna ◽  
Pacific Oyster ◽  
Chromosomal Location ◽  
The Pacific

scholarly journals Determination of the 1,3- and 2-Positional Distribution of Fatty Acids in Olive Oil Triacylglycerols by 13C Nuclear Magnetic Resonance Spectroscopy

2006 ◽  
Vol 89 (4) ◽  
pp. 1071-1076 ◽  
Author(s):  
Giovanna Vlahov
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Fatty Acid ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Olive Oil ◽  
Distribution Pattern ◽  
Random Distribution ◽  
Linear Models ◽  
13C Nuclear Magnetic Resonance ◽  
Nuclear Magnetic

Abstract Linear models were selected from a large data set acquired for Italian olive oil samples by quantitative 13C nuclear magnetic resonance (NMR) spectroscopy with distortionless enhancement by polarization transfer (DEPT). The models were used to determine the composition of the 2 fatty acid pools esterifying the 1,3- and 2-positions of triacylglycerols. The linear models selected proved that the 1,3- and 2-distribution of saturated, oleate, and linoleate chains in olive oil triacylglycerols deviated from the random distribution pattern to an extent that depended on the concentration of the fatty acid in the whole triacylglycerol. To calculate the fatty acid composition of the 1,3- and 2-positions of olive oil triacylglycerols, the equations of the selected linear models were applied to the fatty acid percentages determined by gas chromatography. These data were compared with the values predicted by the computer method (used to determine the theoretical amounts of triacylglycerols), which is based on the 1,3-random-2-random theory of the fatty acid distribution in triacylglycerols. The biggest differences were found in the linoleate chain, which is the chain that deviated the most from a random distribution pattern. The results confirmed that the 1,3-random-2-random distribution theory provides an approximate method for determining the structure of triacylglycerols; however, the linear models calculated by the direct method that applies 13C NMR spectroscopy represent a more precise measurement of the composition of the 2 fatty acid pools esterifying the 1,3- and 2-positions of triacylglycerols.

Guild distribution of some termites from cerrado vegetation in south-east Brazil

1991 ◽  
Vol 7 (4) ◽  
pp. 523-529 ◽  
Author(s):  
Terezinha Abreu Gontijo ◽  
Denize Junqueira Domingos
Keyword(s):  
Organic Matter ◽  
Spatial Distribution ◽  
Resource Partitioning ◽  
Random Distribution ◽  
Food Preferences ◽  
General Distribution ◽  
Nearest Neighbour ◽  
Termite Species ◽  
Cerrado Vegetation ◽  
Distributional Patterns

ABSTRACTThe distributional patterns and food preferences of some cerrado vegetation termites were studied in an area of 2500 m2 in south-east Brazil. All the termitaria were mapped and opened for identification of the species present. Their spatial distribution was studied using the nearest neighbour method (Clark & Evans 1954). We found 46 termite species in 450 nests. The majority of them were wood feeders. The general distribution of termitaria was regular. The distributional patterns of grass and litter feeders were not significantly different from a random distribution. Soil and organic matter feeders were contagiously distributed. The distribution of wood feeders was also contagious. Their spatial distribution was largely influenced by the distribution of the species Nasutitermes sp. 1 and Armitermes euamignathus. These two species occurred in two distinct patches, suggesting resource partitioning.

scholarly journals The Near Threatened Eurasian otter Lutra lutra in Morocco: no sign of recovery

Oryx ◽  
2012 ◽  
Vol 46 (2) ◽  
pp. 249-252 ◽  
Author(s):  
Miguel Delibes ◽  
Javier Calzada ◽  
Miguel Clavero ◽  
Néstor Fernández ◽  
Carlos Gutiérrez-Expósito ◽  
...  
Keyword(s):  
Water Pollution ◽  
Distribution Pattern ◽  
Environmental Policies ◽  
General Distribution ◽  
Lutra Lutra ◽  
River Bank ◽  
High Atlas ◽  
Eurasian Otter ◽  
Western Morocco ◽  
Near Threatened

AbstractAlthough the Near Threatened Eurasian otter Lutra lutra has been recovering in Europe since the 1980s nothing is known about population trends of the species in northern Africa. Ninety sites was searched for signs of otters in northern and western Morocco in 1983 and we repeated this survey in 2011. At each site we searched for otter spraints (faeces) or clear footprints along a maximum of 600 m of river bank, ending the search when the first sign was found. Overall results were strikingly similar in 1983 and 2011, with 36 positive sites and the same general distribution pattern of the species. Healthy otter populations appear to remain in the foothills of the Middle and High Atlas but the trend of populations disappearing from the relatively flat Atlantic slope has increased. The results are in clear contrast with the recovery of otter populations in Europe, probably because of differences in the implementation of environmental policies, especially regarding water pollution.

Satellite DNA in Plants: More than Just Rubbish

2015 ◽  
Vol 146 (2) ◽  
pp. 153-170 ◽  
Author(s):  
Manuel A. Garrido-Ramos
Keyword(s):  
Dna Sequences ◽  
Satellite Dna ◽  
Dna Repeats ◽  
Satellite Dnas ◽  
Factors Affecting ◽  
Functional Roles ◽  
Tandem Repeat Sequences ◽  
Satellite Repeats ◽  
History Of ◽  
Main Components

For decades, satellite DNAs have been the hidden part of genomes. Initially considered as junk DNA, there is currently an increasing appreciation of the functional significance of satellite DNA repeats and of their sequences. Satellite DNA families accumulate in the heterochromatin in different parts of the eukaryotic chromosomes, mainly in pericentromeric and subtelomeric regions, but they also span the functional centromere. Tandem repeat sequences may spread from subtelomeric to interstitial loci, leading to the formation of chromosome-specific loci or to the accumulation in equilocal sites in different chromosomes. They also appear as the main components of the heterochromatin in the sex-specific region of sex chromosomes. Satellite DNA, required for chromosome organization, also plays a role in pairing and segregation. Some satellite repeats are transcribed and can participate in the formation and maintenance of heterochromatin structure and in the modulation of gene expression. In addition to the identification of the different satellite DNA families, their characteristics and location, we are interested in determining their impact on the genomes, by identifying the mechanisms leading to their appearance and amplification as well as in understanding how they change over time, the factors affecting these changes, and the influence exerted by the evolutionary history of the organisms. On the other hand, satellite DNA sequences are rapidly evolving sequences that may cause reproductive barriers between organisms and promote speciation. The accumulation of experimental data collected in recent years and the emergence of new approaches based on next-generation sequencing and high-throughput genome analysis are opening new perspectives that are changing our understanding of satellite DNA. This review examines recent data to provide a timely update on the overall information gathered about this part of the genome, focusing on the advances in the knowledge of its origin, its evolution, and its potential functional roles.

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