scholarly journals A partial map of the circular mitochondrial genome of Drosophila melanogaster. Location of EcoRI-sensitive sites and the adenine-thymine-rich region.

1976 ◽  
Vol 71 (2) ◽  
pp. 434-448 ◽  
Author(s):  
D R Wolstenholme ◽  
C M Fauron

The mitochondrial genome of Drosophila melanogaster is a circular DNA molecule of mol wt 12.35 X 10(6) daltons. A single region accounting for approx. 25% of this molecule can be reproducibly differentially denatured presumably because it is rich in adenine and thymine. We have mapped on the circular mitochondrial genome of D. melanogaster the relative positions of this adenine-thymine (A-T) rich region and the sites sensitive to cleavage by the restriction endonuclease EcoRI, using agarose gel electrophoresis and electron microscopy. Digestion of mitochondrial DNA (mtDNA) molecules to completion with EcoRI resulted in the production of four fragments, A, B, C, and D which represent (+/- SD) 58.9 +/- 1.1%, 27.5 +/- 0.8%, 8.9 +/- 0.5%, and 4.5 +/- 0.3%, of the circular genome length, respectively. Fragments produced by EcoRI digestion and circularized by incubation at 2 degrees C also fell into four distinct length groups with means (+/- SD) of 59.1 +/- 0.5%, 27.5 +/- 0.5%, 9.2 +/- 0.3%, and 4.6 +/- 0.2% of the circular genome length. From a consideration of the lengths of fragments resulting from incomplete EcoRI digestion, it was determined that the arrangement of the fragments in the circular genome was A-C-B-D. By electron microscope examination of partially denatured EcoRI fragments, the A-T-rich region was shown to be located in the A fragment closer to one end than to the other. By similar partial-denaturation studies of fragments resulting from incomplete EcoRI digestion, it was determined that, in the circular genome, of the two EcoRI sites which define the limits of the A fragment, the site between the A and D fragment lies nearest to the A-T-rich region.

2017 ◽  
Author(s):  
Gisele Lopes Nunes ◽  
Renato Renison Moreira Oliveira ◽  
Eder Soares Pires ◽  
Santelmo Vasconcelos ◽  
Thadeu Pietrobon ◽  
...  

AbstractWe report the complete mitochondrial genome sequence of Glomeridesmus spelaeus, the first sequenced genome of the order Gomeridesmida. The genome is 14,825 pb in length and encodes 37 mitochondrial (13 PCGs, 2 rRNA genes, 22 tRNA) genes and contains a typical AT-rich region. The base composition of the genome was A (40.1%), T (36.4%), C (15.8%), and G (7.6%), with an AT content of 76.5%. Our results indicated that Glomeridesmus spelaeus only distantly related to the other Diplopoda species with available mitochondrial genomes in the public databases. The publication of the mitogenome of G. spelaeus will contribute to the identification of troglobitic invertebrates, a very significant advance for the conservation of the troglofauna.


Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 358
Author(s):  
Joan Pedrola-Monfort ◽  
David Lázaro-Gimeno ◽  
Carlos G. Boluda ◽  
Laia Pedrola ◽  
Alfonso Garmendia ◽  
...  

Among the most intriguing mysteries in the evolutionary biology of photosynthetic organisms are the genesis and consequences of the dramatic increase in the mitochondrial and nuclear genome sizes, together with the concomitant evolution of the three genetic compartments, particularly during the transition from water to land. To clarify the evolutionary trends in the mitochondrial genome of Archaeplastida, we analyzed the sequences from 37 complete genomes. Therefore, we utilized mitochondrial, plastidial and nuclear ribosomal DNA molecular markers on 100 species of Streptophyta for each subunit. Hierarchical models of sequence evolution were fitted to test the heterogeneity in the base composition. The best resulting phylogenies were used for reconstructing the ancestral Guanine-Cytosine (GC) content and equilibrium GC frequency (GC*) using non-homogeneous and non-stationary models fitted with a maximum likelihood approach. The mitochondrial genome length was strongly related to repetitive sequences across Archaeplastida evolution; however, the length seemed not to be linked to the other studied variables, as different lineages showed diverse evolutionary patterns. In contrast, Streptophyta exhibited a powerful positive relationship between the GC content, non-coding DNA, and repetitive sequences, while the evolution of Chlorophyta reflected a strong positive linear relationship between the genome length and the number of genes.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yu Sun ◽  
Hua Huang ◽  
Yudong Liu ◽  
Shanshan Liu ◽  
Jun Xia ◽  
...  

AbstractIn this study, we analyzed the complete mitochondrial genome (mitogenome) of Speiredonia retorta, which is a pest and a member of the Lepidoptera order. In total, the S. retorta mitogenome was found to contain 15,652 base pairs encoding 13 protein-coding genes (PCGs), 22 tRNAs, 2 rRNAs, as well as an adenine (A) + thymine (T)-rich region. These findings were consistent with the mitogenome composition of other lepidopterans, as we identified all 13 PCGs beginning at ATN codons. We also found that 11 PCGs terminated with canonical stop codons, whereas cox2 and nad4 exhibited incomplete termination codons. By analyzing the mitogenome of S. retorta using Bayesian inference (BI) and maximum likelihood (ML) models, we were able to further confirm that this species is a member of the Erebidae family.


1982 ◽  
Vol 39 (2) ◽  
pp. 149-156 ◽  
Author(s):  
R. Appels ◽  
A. J. Hilliker

SummaryThe proximal breakpoints of the inversion chromosomes In(1)ωm4 and In(1)m51b were shown, by in situ hybridization, to define the boundaries of the ribosomal DNA region located within the X chromosome heterochromatin (Xh). We estimate that at least 95% of the rDNA is located between the In(1)ωm4 and In(1)ωm51b proximal breakpoints. In contrast only 60–70% of the Type I intervening sequences located in Xh are located between these breakpoints. The Type I intervening sequences in the rDNA region occur as inserts in the 28S rRNA sequences while the remainder of the sequences are distal to the In(1)ωm4 breakpoint and not associated with rRNA genes.The regions of Xh which contain rDNA and Type I intervening sequences were related to regions shown by Cooper (1964) to contribute to meiotic pairing between the X and Y chromosomes in male Drosophila. We demonstrate that the rRNA coding region contributes to X / Y pairing. However, no single region of Xh is required for fidelity of male meiotic pairing of the sex chromosomes.


Genetics ◽  
1980 ◽  
Vol 95 (2) ◽  
pp. 355-366
Author(s):  
Richard L Roehrdanz ◽  
John C Lucchesi

ABSTRACT The Drosophila melanogaster genome contains a single region (at 83DE on the polytene chromosome map) for which both heterozygous deficiency and heterozygous duplication are inviable. Seven EMS-induced mutations have been recovered that are viable in combination with a duplication of this region. Two classes of mutations are reported: (1) Mutations that allow survival of flies with either a duplication or a normal third chromosome. These mutations retain Ki, a closely linked marker on the mutagenized chromosome. They fail to complement, and one has been mapped to the vicinity of 83DE. (2) Mutations that allow survival only in heterozygous combination with a duplication and have lost the Ki marker. These mutations represent new deletions of the dose-sensitive information. The possible structural organization of the 83DE region is discussed in light of these two classes of mutations.


2021 ◽  
Author(s):  
Vincent Delafont ◽  
Mégane Gasqué ◽  
Yann Héchard

AbstractA hybrid sequencing approach, using short and long reads sequencing, was employed for characterizing the genomes of the free-living amoeba host Vermamoeba vermiformis, along with its Dependentiae endosymbiont Vermiphilus pyriformis. The amoeba host reconstructed nuclear genome is 39.5 Mb, and its full mitochondrial genome is 61.7 kb. The closed, circular genome of the Dependentiae endosymbiont Vermiphilus pyriformis, naturally infecting V. vermiformis is 1.1 Mb.


Zootaxa ◽  
2020 ◽  
Vol 4821 (3) ◽  
pp. 533-552
Author(s):  
LINGLING WU ◽  
XIAOLI JIANG ◽  
FENGJIAO XIE ◽  
SAIMA KAUSAR ◽  
DAN LIANG ◽  
...  

In the present study, the complete mitochondrial genome of Smerinthus planus Walker (Lepidoptera: Sphingidae) was sequenced and analyzed to add additional traits for expanding our knowledge on systematics and phylogenetics of world-wide studied Sphingidae moths. The mitochondrial genome is a circular double-stranded DNA molecule, 15368 bp in size. It includes 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, twenty-two transfer RNA (tRNA) genes, and an adenine (A) + thymine (T) rich region. All the PCGs start with the typical ATN start codons, except for the nad5 gene, which initiates with TTA. The codon usage analysis revealed that Phe, Ile, Lys, Leu, Asn, and Tys were the most common amino acids, while Cys and Trp were least common. Among the 13 PCGs, nine genes harbor the complete termination codon TAA, whereas the remaining four genes (nad1, cob, nad4, and nad3) terminate with TAG. The A+T rich region of S. planus is 318 bp. This region displays the highest A+T rich content, accounting for 91.50%, with both AT skew (-0.09) and GC skew (-0.26) are negative. Like other Lepidopterans, the A+T-rich region of the S. planus also contains some conserved regions, including the motif ‘ATAGA’ followed by an 18 bp poly-T stretch, a microsatellite-like (AT)8 and a poly-A element. Phylogenetic relationships, based on nucleotide sequences from the genomes of 31 species, confirmed that S. planus belong to the Sphingidae family. This study is aimed to improve the mitochondrial genome database of moths and provide valuable information for studying the genetic evolution and phylogeny of Lepidopteran species.


2020 ◽  
Vol 287 (1937) ◽  
pp. 20200469
Author(s):  
J. Arvid Ågren ◽  
Manisha Munasinghe ◽  
Andrew G. Clark

The coordination between mitochondrial and nuclear genes is crucial to eukaryotic organisms. Predicting the nature of these epistatic interactions can be difficult because of the transmission asymmetry of the genes involved. While autosomes and X-linked genes are transmitted through both sexes, genes on the Y chromosome and in the mitochondrial genome are uniparentally transmitted through males and females, respectively. Here, we generate 36 otherwise isogenic Drosophila melanogaster strains differing only in the geographical origin of their mitochondrial genome and Y chromosome, to experimentally examine the effects of the uniparentally inherited parts of the genome, as well as their interaction, in males. We assay longevity and gene expression through RNA-sequencing. We detect an important role for both mitochondrial and Y-linked genes, as well as extensive mitochondrial-Y chromosome epistasis. In particular, genes involved in male reproduction appear to be especially sensitive to such interactions, and variation on the Y chromosome is associated with differences in longevity. Despite these interactions, we find no evidence that the mitochondrial genome and Y chromosome are co-adapted within a geographical region. Overall, our study demonstrates a key role for the uniparentally inherited parts of the genome for male biology, but also that mito-nuclear interactions are complex and not easily predicted from simple transmission asymmetries.


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