Intron loss from the NADH dehydrogenase subunit 4 gene of lettuce mitochondrial DNA: evidence for homologous recombination of a cDNA intermediate

1994 ◽  
Vol 243 (1) ◽  
pp. 97-105 ◽  
Author(s):  
K. T. Geiss ◽  
G. M. Abbas ◽  
C. A. Makaroff
2005 ◽  
Vol 86 (1) ◽  
pp. 1-11 ◽  
Author(s):  
LAURENCE MOUSSON ◽  
CATHERINE DAUGA ◽  
THOMAS GARRIGUES ◽  
FRANCIS SCHAFFNER ◽  
MARIE VAZEILLE ◽  
...  

Aedes (Stegomyia) aegypti (L.) and Aedes (Stegomyia) albopictus (Skuse) are the most important vectors of the dengue and yellow-fever viruses. Both took advantage of trade developments to spread throughout the tropics from their native area: A. aegypti originated from Africa and A. albopictus from South-East Asia. We investigated the relationships between A. aegypti and A. albopictus mosquitoes based on three mitochondrial-DNA genes (cytochrome b, cytochrome oxidase I and NADH dehydrogenase subunit 5). Little genetic variation was observed for A. albopictus, probably owing to the recent spreading of the species via human activities. For A. aegypti, most populations from South America were found to be genetically similar to populations from South-East Asia (Thailand and Vietnam), except for one sample from Boa Vista (northern Amazonia), which was more closely related to samples from Africa (Guinea and Ivory Coast). This suggests that African populations of A. aegypti introduced during the slave trade have persisted in Boa Vista, resisting eradication campaigns.


The Auk ◽  
2005 ◽  
Vol 122 (4) ◽  
pp. 1271-1280
Author(s):  
Ben D. Marks ◽  
David E. Willard

Abstract The avifauna of Madagascar presents a complicated taxonomic and biogeographic problem. Although Madagascar was once connected to Africa, the birds of the island are not all of African origin. The Madagascar Pygmy Kingfisher (Ispidina madagascariensis) is sometimes placed in the African genus Ispidina and sometimes in the Southeast Asian genus Ceyx. We sequenced 755 base pairs of mitochondrial DNA from a fragment of the NADH dehydrogenase subunit II (ND2) and from the complete NADH dehydrogenase subunit III (ND3). We used these data to construct phylogenetic hypotheses for the Alcedinidae. Using these phylogenies, we evaluate previous hypotheses of relationships of I. madagascariensis. Although we cannot reject the hypothesis that I. madagascariensis is indeed a member of Ispidina, tree-building analyses support a relationship not with Ispidina or Ceyx, but instead with members of the African genus Corythornis. These data suggest that certain behaviors and plumage types have evolved several times in the Alcedinidae. Relations Phylogénétiques de Ispidina madagascariensis


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
John A. Ohiolei ◽  
Joshua Luka ◽  
Guo-Qiang Zhu ◽  
Hong-Bin Yan ◽  
Li Li ◽  
...  

Abstract Background Cysticercosis caused by the metacestode larval stage of Taenia hydatigena is a disease of veterinary and economic importance. A considerable level of genetic variation among isolates of different intermediate hosts and locations has been documented. Generally, data on the genetic population structure of T. hydatigena is scanty and lacking in Nigeria. Meanwhile, similar findings in other cestodes like Echinococcus spp. have been found to be of epidemiological importance. Our aim, therefore, was to characterize and compare the genetic diversity of T. hydatigena population in Nigeria based on three mitochondrial DNA markers as well as to assess the phylogenetic relationship with populations from other geographical regions. Methods In the present study, we described the genetic variation and diversity of T. hydatigena isolates from Nigerian sheep and goats using three full-length mitochondrial genes: the cytochrome c oxidase subunit 1 (cox1), NADH dehydrogenase subunit 1 (nad1), and NADH dehydrogenase subunit 5 (nad5). Results The median-joining network of concatenated cox1-nad1-nad5 sequences indicated that T. hydatigena metacestodes of sheep origin were genetically distinct from those obtained in goats and this was supported by high FST values of nad1, cox1, and concatenated cox1-nad1-nad5 sequences. Genetic variation was also found to be higher in isolates from goats than from sheep. Conclusions To the best of our knowledge, the present study described the genetic variation of T. hydatigena population for the first time in Nigeria using full-length mitochondrial genes and suggests the existence of host-specific variants. The population indices of the different DNA markers suggest that analysis of long mitochondrial DNA fragments may provide more information on the molecular ecology of T. hydatigena. We recommend that future studies employ long mitochondrial DNA sequence in order to provide reliable data that would explain the extent of genetic variation in different hosts/locations and the biological and epidemiological significance.


2015 ◽  
Vol 128 (12) ◽  
pp. 895-904 ◽  
Author(s):  
Grainne S. Gorman ◽  
Emma L. Blakely ◽  
Hue-Tran Hornig-Do ◽  
Helen A.L. Tuppen ◽  
Laura C. Greaves ◽  
...  

Complex I (CI) is the largest of the five multi-subunit complexes constituting the human oxidative phosphorylation (OXPHOS) system. Seven of its catalytic core subunits are encoded by mitochondrial DNA (ND (NADH dehydrogenase)1–6, ND4L (NADH dehydrogenase subunit 4L)), with mutations in all seven having been reported in association with isolated CI deficiency. We investigated two unrelated adult patients presenting with marked exercise intolerance, persistent lactic acidaemia and severe muscle-restricted isolated CI deficiency associated with sub-sarcolemmal mitochondrial accumulation. Screening of the mitochondrial genome detected novel mutations in the MTND1 (NADH dehydrogenase subunit 1) gene, encoding subunit of CI [Patient 1, m.3365T>C predicting p.(Leu20Pro); Patient 2, m.4175G>A predicting p.(Trp290*)] at high levels of mitochondrial DNA heteroplasmy in skeletal muscle. We evaluated the effect of these novel MTND1 mutations on complex assembly showing that CI assembly, although markedly reduced, was viable in the absence of detectable ND1 signal. Real-time PCR and Western blotting showed overexpression of different CI assembly factor transcripts and proteins in patient tissue. Together, our data indicate that the mechanism underlying the expression of the biochemical defect may involve a compensatory response to the novel MTND1 gene mutations, promoting assembly factor up-regulation and stabilization of respiratory chain super-complexes, resulting in partial rescue of the clinical phenotype.


Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 409-421 ◽  
Author(s):  
Cheryl A Wise ◽  
Michaela Sraml ◽  
Simon Easteal

Abstract To test whether patterns of mitochondrial DNA (mtDNA) variation are consistent with a neutral model of molecular evolution, nucleotide sequences were determined for the 1041 bp of the NADH dehydrogenase subunit 2 (ND2) gene in 20 geographically diverse humans and 20 common chimpanzees. Contingency tests of neutrality were performed using four mutational categories for the ND2 molecule: synonymous and nonsynonymous mutations in the transmembrane regions, and synonymous and nonsynonymous mutations in the surface regions. The following three topological mutational categories were also used: intraspecific tips, intraspecific interiors, and interspecific fixed differences. The analyses reveal a significantly greater number of nonsynonymous polymorphisms within human transmembrane regions than expected based on interspecific comparisons, and they are inconsistent with a neutral equilibrium model. This pattern of excess nonsynonymous polymorphism is not seen within chimpanzees. Statistical tests of neutrality, such as Tajima's D test, and the D and F tests proposed by Fu and Li, indicate an excess of low frequency polymorphisms in the human data, but not in the chimpanzee data. This is consistent with recent directional selection, a population bottleneck or background selection of slightly deleterious mutations in human mtDNA samples. The analyses further support the idea that mitochondrial genome evolution is governed by selective forces that have the potential to affect its use as a “neutral” marker in evolutionary and population genetic studies.


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