Displaying publications 21 - 40 of 262 in total

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  1. Fulltext Accumulation of Mitochondrial DNA Microsatellite Instability in Malaysian Patients with Primary Central Nervous System Tumors
    Radzak S, Khair Z, Ahmad F, Idris Z, Yusoff A
    Turk Neurosurg, 2021;31(1):99-106.
    PMID: 33491172 DOI: 10.5137/1019-5149.JTN.27893-20.4
    AIM: To determine the mitochondrial microsatellite instability (mtMSI) status in a series of Malaysian patients with brain tumors. Furthermore, we analyzed whether the mtMSI status is associated with the clinicopathological features of the patients.

    MATERIAL AND METHODS: Forty fresh frozen tumor tissues along with blood samples of brain tumor patients were analyzed for mtMSI by PCR amplification of genomic DNAs, and the amplicons were directly sequenced in both directions using Sanger sequencing.

    RESULTS: Microsatellite analysis revealed that 20% (8 out of 40) of the tumors were mtMSI positive with a total of 8 mtMSI changes. All mtMSI markers were detected in D310 and D16184 of the D-loop region. Additionally, no significant association was observed between mtMSI status and clinicopathological features.

    CONCLUSION: The variations, specifically the mtMSI, suggest that the mitochondrial DNA (mtDNA) can be targeted for genomic alteration in brain tumors. Therefore, the specific role of mtDNA alteration in brain tumor development and prognosis requires further investigation.

    Matched MeSH terms: DNA, Mitochondrial/genetics*
  2. Fulltext Sequence variation in the cytochrome oxidase subunit I and II genes of two commonly found blow fly species, Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae) in Malaysia
    Tan SH, Aris EM, Surin J, Omar B, Kurahashi H, Mohamed Z
    Trop Biomed, 2009 Aug;26(2):173-81.
    PMID: 19901904
    The mitochondiral DNA region encompassing the cytochrome oxidase subunit I (COI) and cytochrome oxidase subunit II (COII) genes of two Malaysian blow fly species, Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) were studied. This region, which spans 2303bp and includes the COI, tRNA leucine and partial COII was sequenced from adult fly and larval specimens, and compared. Intraspecific variations were observed at 0.26% for Ch. megacephala and 0.17% for Ch. rufifacies, while sequence divergence between the two species was recorded at a minimum of 141 out of 2303 sites (6.12%). Results obtained in this study are comparable to published data, and thus support the use of DNA sequence to facilitate and complement morphology-based species identification.
    Matched MeSH terms: DNA, Mitochondrial/genetics
  3. Fulltext Phylogeography, colouration, and cryptic speciation across the Indo-Pacific in the sea urchin genus Echinothrix
    Coppard SE, Jessop H, Lessios HA
    Sci Rep, 2021 Aug 16;11(1):16568.
    PMID: 34400682 DOI: 10.1038/s41598-021-95872-0
    The sea urchins Echinothrix calamaris and Echinothrix diadema have sympatric distributions throughout the Indo-Pacific. Diverse colour variation is reported in both species. To reconstruct the phylogeny of the genus and assess gene flow across the Indo-Pacific we sequenced mitochondrial 16S rDNA, ATPase-6, and ATPase-8, and nuclear 28S rDNA and the Calpain-7 intron. Our analyses revealed that E. diadema formed a single trans-Indo-Pacific clade, but E. calamaris contained three discrete clades. One clade was endemic to the Red Sea and the Gulf of Oman. A second clade occurred from Malaysia in the West to Moorea in the East. A third clade of E. calamaris was distributed across the entire Indo-Pacific biogeographic region. A fossil calibrated phylogeny revealed that the ancestor of E. diadema diverged from the ancestor of E. calamaris ~ 16.8 million years ago (Ma), and that the ancestor of the trans-Indo-Pacific clade and Red Sea and Gulf of Oman clade split from the western and central Pacific clade ~ 9.8 Ma. Time since divergence and genetic distances suggested species level differentiation among clades of E. calamaris. Colour variation was extensive in E. calamaris, but not clade or locality specific. There was little colour polymorphism in E. diadema.
    Matched MeSH terms: DNA, Mitochondrial/genetics
  4. Fulltext Plasmodium knowlesi: reservoir hosts and tracking the emergence in humans and macaques
    Lee KS, Divis PC, Zakaria SK, Matusop A, Julin RA, Conway DJ, et al.
    PLoS Pathog, 2011 Apr;7(4):e1002015.
    PMID: 21490952 DOI: 10.1371/journal.ppat.1002015
    Plasmodium knowlesi, a malaria parasite originally thought to be restricted to macaques in Southeast Asia, has recently been recognized as a significant cause of human malaria. Unlike the benign and morphologically similar P. malariae, these parasites can lead to fatal infections. Malaria parasites, including P. knowlesi, have not yet been detected in macaques of the Kapit Division of Malaysian Borneo, where the majority of human knowlesi malaria cases have been reported. In order to extend our understanding of the epidemiology and evolutionary history of P. knowlesi, we examined 108 wild macaques for malaria parasites and sequenced the circumsporozoite protein (csp) gene and mitochondrial (mt) DNA of P. knowlesi isolates derived from macaques and humans. We detected five species of Plasmodium (P. knowlesi, P. inui, P. cynomolgi, P. fieldi and P. coatneyi) in the long-tailed and pig-tailed macaques, and an extremely high prevalence of P. inui and P. knowlesi. Macaques had a higher number of P. knowlesi genotypes per infection than humans, and some diverse alleles of the P. knowlesi csp gene and certain mtDNA haplotypes were shared between both hosts. Analyses of DNA sequence data indicate that there are no mtDNA lineages associated exclusively with either host. Furthermore, our analyses of the mtDNA data reveal that P. knowlesi is derived from an ancestral parasite population that existed prior to human settlement in Southeast Asia, and underwent significant population expansion approximately 30,000-40,000 years ago. Our results indicate that human infections with P. knowlesi are not newly emergent in Southeast Asia and that knowlesi malaria is primarily a zoonosis with wild macaques as the reservoir hosts. However, ongoing ecological changes resulting from deforestation, with an associated increase in the human population, could enable this pathogenic species of Plasmodium to switch to humans as the preferred host.
    Matched MeSH terms: DNA, Mitochondrial/genetics; DNA, Mitochondrial/isolation & purification
  5. Fulltext Mitochondrial Respiration Is Reduced in Atherosclerosis, Promoting Necrotic Core Formation and Reducing Relative Fibrous Cap Thickness
    Yu EPK, Reinhold J, Yu H, Starks L, Uryga AK, Foote K, et al.
    Arterioscler Thromb Vasc Biol, 2017 12;37(12):2322-2332.
    PMID: 28970293 DOI: 10.1161/ATVBAHA.117.310042
    OBJECTIVE: Mitochondrial DNA (mtDNA) damage is present in murine and human atherosclerotic plaques. However, whether endogenous levels of mtDNA damage are sufficient to cause mitochondrial dysfunction and whether decreasing mtDNA damage and improving mitochondrial respiration affects plaque burden or composition are unclear. We examined mitochondrial respiration in human atherosclerotic plaques and whether augmenting mitochondrial respiration affects atherogenesis.

    APPROACH AND RESULTS: Human atherosclerotic plaques showed marked mitochondrial dysfunction, manifested as reduced mtDNA copy number and oxygen consumption rate in fibrous cap and core regions. Vascular smooth muscle cells derived from plaques showed impaired mitochondrial respiration, reduced complex I expression, and increased mitophagy, which was induced by oxidized low-density lipoprotein. Apolipoprotein E-deficient (ApoE-/-) mice showed decreased mtDNA integrity and mitochondrial respiration, associated with increased mitochondrial reactive oxygen species. To determine whether alleviating mtDNA damage and increasing mitochondrial respiration affects atherogenesis, we studied ApoE-/- mice overexpressing the mitochondrial helicase Twinkle (Tw+/ApoE-/-). Tw+/ApoE-/- mice showed increased mtDNA integrity, copy number, respiratory complex abundance, and respiration. Tw+/ApoE-/- mice had decreased necrotic core and increased fibrous cap areas, and Tw+/ApoE-/- bone marrow transplantation also reduced core areas. Twinkle increased vascular smooth muscle cell mtDNA integrity and respiration. Twinkle also promoted vascular smooth muscle cell proliferation and protected both vascular smooth muscle cells and macrophages from oxidative stress-induced apoptosis.

    CONCLUSIONS: Endogenous mtDNA damage in mouse and human atherosclerosis is associated with significantly reduced mitochondrial respiration. Reducing mtDNA damage and increasing mitochondrial respiration decrease necrotic core and increase fibrous cap areas independently of changes in reactive oxygen species and may be a promising therapeutic strategy in atherosclerosis.

    Matched MeSH terms: DNA, Mitochondrial/genetics; DNA, Mitochondrial/metabolism*
  6. Reduced mitochondrial DNA content in lymphocytes is associated with insulin resistance and inflammation in patients with impaired fasting glucose
    Abu Bakar MH, Hairunisa N, Zaman Huri H
    Clin Exp Med, 2018 Aug;18(3):373-382.
    PMID: 29550985 DOI: 10.1007/s10238-018-0495-4
    Altered mitochondrial DNA (mtDNA) is the most common denominator to numerous metabolic diseases. The present study sought to investigate the correlation between mtDNA content in lymphocytes and associated clinical risk factors for impaired fasting glucose (IFG). We included 23 healthy control and 42 IFG participants in this cross-sectional study. The measurements of mtDNA content in lymphocytes and pro-inflammatory markers derived from both normal and diseased individuals were quantified. Spearman partial correlation and multivariate statistical analyses were employed to evaluate the association between mtDNA content and other metabolic covariates in IFG. Reduced mtDNA content was observed in the IFG group with microvascular complications than those without complications. The IFG patients with lowest median of mtDNA content had considerably elevated hyperglycemia, insulin resistance and inflammation. The adjusted partial correlation analysis showed that mtDNA content was positively correlated with HDL-cholesterol and IL-10 (P 
    Matched MeSH terms: DNA, Mitochondrial/blood*; DNA, Mitochondrial/immunology
  7. Fulltext Mitochondrial DNA markers reveal high genetic diversity but low genetic differentiation in the black fly Simulium tani Takaoka & Davies along an elevational gradient in Malaysia
    Low VL, Adler PH, Takaoka H, Ya'cob Z, Lim PE, Tan TK, et al.
    PLoS One, 2014;9(6):e100512.
    PMID: 24941043 DOI: 10.1371/journal.pone.0100512
    The population genetic structure of Simulium tani was inferred from mitochondria-encoded sequences of cytochrome c oxidase subunits I (COI) and II (COII) along an elevational gradient in Cameron Highlands, Malaysia. A statistical parsimony network of 71 individuals revealed 71 haplotypes in the COI gene and 43 haplotypes in the COII gene; the concatenated sequences of the COI and COII genes revealed 71 haplotypes. High levels of genetic diversity but low levels of genetic differentiation were observed among populations of S. tani at five elevations. The degree of genetic diversity, however, was not in accordance with an altitudinal gradient, and a Mantel test indicated that elevation did not have a limiting effect on gene flow. No ancestral haplotype of S. tani was found among the populations. Pupae with unique structural characters at the highest elevation showed a tendency to form their own haplotype cluster, as revealed by the COII gene. Tajima's D, Fu's Fs, and mismatch distribution tests revealed population expansion of S. tani in Cameron Highlands. A strong correlation was found between nucleotide diversity and the levels of dissolved oxygen in the streams where S. tani was collected.
    Matched MeSH terms: DNA, Mitochondrial/genetics*
  8. Fulltext Mitochondrial hepatopathies: advances in genetics, therapeutic approaches, and outcomes
    Lee WS, Sokol RJ
    J Pediatr, 2013 Oct;163(4):942-8.
    PMID: 23810725 DOI: 10.1016/j.jpeds.2013.05.036
    Matched MeSH terms: DNA, Mitochondrial/genetics
  9. Fulltext Development of swine-specific DNA markers for biosensor-based halal authentication
    Ali ME, Hashim U, Kashif M, Mustafa S, Che Man YB, Abd Hamid SB
    Genet. Mol. Res., 2012;11(2):1762-72.
    PMID: 22843053 DOI: 10.4238/2012.June.29.9
    The pig (Sus scrofa) mitochondrial genome was targeted to design short (15-30 nucleotides) DNA markers that would be suitable for biosensor-based hybridization detection of target DNA. Short DNA markers are reported to survive harsh conditions in which longer ones are degraded into smaller fragments. The whole swine mitochondrial-genome was in silico digested with AluI restriction enzyme. Among 66 AluI fragments, five were selected as potential markers because of their convenient lengths, high degree of interspecies polymorphism and intraspecies conservatism. These were confirmed by NCBI blast analysis and ClustalW alignment analysis with 11 different meat-providing animal and fish species. Finally, we integrated a tetramethyl rhodamine-labeled 18-nucleotide AluI fragment into a 3-nm diameter citrate-tannate coated gold nanoparticle to develop a swine-specific hybrid nanobioprobe for the determination of pork adulteration in 2.5-h autoclaved pork-beef binary mixtures. This hybrid probe detected as low as 1% pork in deliberately contaminated autoclaved pork-beef binary mixtures and no cross-species detection was recorded, demonstrating the feasibility of this type of probe for biosensor-based detection of pork adulteration of halal and kosher foods.
    Matched MeSH terms: DNA, Mitochondrial/genetics*
  10. Nanoparticle sensor for label free detection of swine DNA in mixed biological samples
    Ali ME, Hashim U, Mustafa S, Man YB, Yusop MH, Bari MF, et al.
    Nanotechnology, 2011 May 13;22(19):195503.
    PMID: 21430321 DOI: 10.1088/0957-4484/22/19/195503
    We used 40 ± 5 nm gold nanoparticles (GNPs) as colorimetric sensor to visually detect swine-specific conserved sequence and nucleotide mismatch in PCR-amplified and non-amplified mitochondrial DNA mixtures to authenticate species. Colloidal GNPs changed color from pinkish-red to gray-purple in 2 mM PBS. Visually observed results were clearly reflected by the dramatic reduction of surface plasmon resonance peak at 530 nm and the appearance of new features in the 620-800 nm regions in their absorption spectra. The particles were stabilized against salt-induced aggregation upon the adsorption of single-stranded DNA. The PCR products, without any additional processing, were hybridized with a 17-base probe prior to exposure to GNPs. At a critical annealing temperature (55 °C) that differentiated matched and mismatched base pairing, the probe was hybridized to pig PCR product and dehybridized from the deer product. The dehybridized probe stuck to GNPs to prevent them from salt-induced aggregation and retained their characteristic red color. Hybridization of a 27-nucleotide probe to swine mitochondrial DNA identified them in pork-venison, pork-shad and venison-shad binary admixtures, eliminating the need of PCR amplification. Thus the assay was applied to authenticate species both in PCR-amplified and non-amplified heterogeneous biological samples. The results were determined visually and validated by absorption spectroscopy. The entire assay (hybridization plus visual detection) was performed in less than 10 min. The LOD (for genomic DNA) of the assay was 6 µg ml(-1) swine DNA in mixed meat samples. We believe the assay can be applied for species assignment in food analysis, mismatch detection in genetic screening and homology studies between closely related species.
    Matched MeSH terms: DNA, Mitochondrial/genetics
  11. First description of the male of Phlebotomus betisi Lewis and Wharton, 1963 (Diptera: Psychodidae)
    Khadri MS, Depaquit J, Bargues MD, Ferté H, Mas-coma S, Lee HL, et al.
    Parasitol Int, 2008 Sep;57(3):295-9.
    PMID: 18378490 DOI: 10.1016/j.parint.2008.01.003
    The male of Phlebotomus (Larroussius) betisi is described from Malayan caves. Several males have been caught in association with P. betisi females. Males and females have been associated by ecology, biogeography, morphology and molecular biology (homology of the ND4 mtDNA sequences).
    Matched MeSH terms: DNA, Mitochondrial/analysis
  12. Fulltext Effects of a sex-ratio distorting endosymbiont on mtDNA variation in a global insect pest
    Delgado AM, Cook JM
    BMC Evol. Biol., 2009;9:49.
    PMID: 19257899 DOI: 10.1186/1471-2148-9-49
    Patterns of mtDNA variation within a species reflect long-term population structure, but may also be influenced by maternally inherited endosymbionts, such as Wolbachia. These bacteria often alter host reproductive biology and can drive particular mtDNA haplotypes through populations. We investigated the impacts of Wolbachia infection and geography on mtDNA variation in the diamondback moth, a major global pest whose geographic distribution reflects both natural processes and transport via human agricultural activities.
    Matched MeSH terms: DNA, Mitochondrial/genetics*
  13. The geography of diversification in mutualistic ants: a gene's-eye view into the Neogene history of Sundaland rain forests
    Quek SP, Davies SJ, Ashton PS, Itino T, Pierce NE
    Mol Ecol, 2007 May;16(10):2045-62.
    PMID: 17498231
    We investigate the geographical and historical context of diversification in a complex of mutualistic Crematogaster ants living in Macaranga trees in the equatorial rain forests of Southeast Asia. Using mitochondrial DNA from 433 ant colonies collected from 32 locations spanning Borneo, Malaya and Sumatra, we infer branching relationships, patterns of genetic diversity and population history. We reconstruct a time frame for the ants' diversification and demographic expansions, and identify areas that might have been refugia or centres of diversification. Seventeen operational lineages are identified, most of which can be distinguished by host preference and geographical range. The ants first diversified 16-20 Ma, not long after the onset of the everwet forests in Sundaland, and achieved most of their taxonomic diversity during the Pliocene. Pleistocene demographic expansions are inferred for several of the younger lineages. Phylogenetic relationships suggest a Bornean cradle and major axis of diversification. Taxonomic diversity tends to be associated with mountain ranges; in Borneo, it is greatest in the Crocker Range of Sabah and concentrated also in other parts of the northern northwest coast. Within-lineage genetic diversity in Malaya and Sumatra tends to also coincide with mountain ranges. A series of disjunct and restricted distributions spanning northern northwest Borneo and the major mountain ranges of Malaya and Sumatra, seen in three pairs of sister lineages, further suggests that these regions were rain-forest refuges during drier climatic phases of the Pleistocene. Results are discussed in the context of the history of Sundaland's rain forests.
    Matched MeSH terms: DNA, Mitochondrial/genetics
  14. Single, rapid coastal settlement of Asia revealed by analysis of complete mitochondrial genomes
    Macaulay V, Hill C, Achilli A, Rengo C, Clarke D, Meehan W, et al.
    Science, 2005 May 13;308(5724):1034-6.
    PMID: 15890885
    A recent dispersal of modern humans out of Africa is now widely accepted, but the routes taken across Eurasia are still disputed. We show that mitochondrial DNA variation in isolated "relict" populations in southeast Asia supports the view that there was only a single dispersal from Africa, most likely via a southern coastal route, through India and onward into southeast Asia and Australasia. There was an early offshoot, leading ultimately to the settlement of the Near East and Europe, but the main dispersal from India to Australia approximately 65,000 years ago was rapid, most likely taking only a few thousand years.
    Matched MeSH terms: DNA, Mitochondrial/genetics*
  15. The association of mitochondrial DNA 5178 C > a polymorphism with plasma lipid levels among three ethnic groups
    Lal S, Madhavan M, Heng CK
    Ann. Hum. Genet., 2005 Nov;69(Pt 6):639-44.
    PMID: 16266403
    Mitochondria are eukaryotic cytoplasmic organelles responsible for oxidative phosphorylation. The C to A nucleotide transversion in the NADH dehydrogenase subunit 2 (MT-ND2) coding region of mitochondrial DNA has been reported to be associated with plasma lipid levels, adult onset diseases and longevity. We have examined the role of this polymorphism in relation to plasma lipid levels and age in a total of 713 healthy individuals belonging to 3 ethnic groups in Singapore. The frequency of the A allele was significantly higher (p < 0.05) among the Chinese (0.15) in comparison to the Malays (0.05) and Indians (0.02). No significant difference in the frequency of the allele was observed between healthy and coronary artery disease subjects, and between age-stratified subjects. We found that the polymorphism is significantly associated in an ethnic- and gender-specific manner with plasma apoB levels in the Chinese males (p < 0.05). This is the first epidemiological report of the mt5178 C > A polymorphism and its association with plasma lipid levels in Asian populations outside Japan.
    Matched MeSH terms: DNA, Mitochondrial/genetics*
  16. Multiple invasions of the Ryukyu Archipelago by Oriental frogs of the subgenus Odorrana with phylogenetic reassessment of the related subgenera of the genus Rana
    Matsui M, Shimada T, Ota H, Tanaka-Ueno T
    Mol Phylogenet Evol, 2005 Dec;37(3):733-42.
    PMID: 15964212
    The genus Rana, notably diversified in Oriental regions from China to Southeast Asia, includes a group of cascade frogs assigned to subgenera Odorrana and Eburana. Among them, R. ishikawae and the R. narina complex represent the northernmost members occurring from Taiwan to the Ryukyu Archipelago of Japan. Relationships of these frogs with the continental members, as well as the history of their invasions to islands, have been unclear. The taxonomic status of Odorrana and related genera varies among authors and no phylogenetic reassessment has been done. Using partial sequences of mitochondrial 12S and 16S rRNA genes, we estimated phylogenetic relationships among 17 species of the section Hylarana including Odorrana and Eburana, and related species from the Ryukyus, Taiwan, China, Thailand, Malaysia, and Indonesia. We estimate that (1) Odorrana is monophyletic and encompasses species of Eburana and R. hosii, which is now placed in Chalcorana, (2) the ancestor of R. ishikawae separated from other Rana in the middle to late Miocene prior to its entry to the Ryukyu Archipelago, (3) the ancestor of the R. narina complex later diversified in continental Asia, and invaded the Ryukyu Archipelago through Taiwan, (4) the R. narina complex attained its current distribution within the Ryukyus through niche segregations, and (5) vicariance of R. hosii between Malay Peninsula and Borneo occurred much later than the divergence events in the R. narina complex. Current subgeneric classification of Rana, at least of Southeast Asian members, requires full reassessment in the light of phylogenetic relationships.
    Matched MeSH terms: DNA, Mitochondrial/genetics
  17. The complete mitochondrial genome of Bactrocera diaphora (Diptera: Tephtitidae)
    Zhang KJ, Liu L, Rong X, Zhang GH, Liu H, Liu YH
    Mitochondrial DNA A DNA Mapp Seq Anal, 2016 11;27(6):4314-4315.
    PMID: 26462416
    We sequenced and annotated the complete mitochondrial genome (mitogenome) of Bactrocera diaphora (Diptera: Tephtitidae), which is an economically important pest in the southwest area of China, India, Sri Lanka, Vietnam and Malaysia. This mitogenome is 15 890 bp in length with an A + T content of 74.103%, and contains 37 typical animal mitochondrial genes that are arranged in the same order as that of the inferred ancestral insects. All protein-coding genes (PCGs) start with a typical ATN codon, except cox1 that begins with TCG. Ten PCGs stop with termination codon TAA or TAG, whereas cox1, nad1 and nad5 have single T-- as the incomplete stop codon. All of the transfer RNA genes present the typical clover leaf secondary structure except trnS1 (AGN) with a looping D-arm. The A + T-rich region is located between rrnS and trnI with a length of 946 bp, and contains a 20 bp poly-T stretch and 22 bp poly-A stretch. Except the control region, the longest intergenic spacer is located between trnR and trnN that is 94 bp long with an excessive high A + T content (95.74%) and a microsatellite-like region (TA)13.
    Matched MeSH terms: DNA, Mitochondrial/genetics*
  18. Fulltext Molecular characterisation of the tick Rhipicephalus microplus in Malaysia: new insights into the cryptic diversity and distinct genetic assemblages throughout the world
    Low VL, Tay ST, Kho KL, Koh FX, Tan TK, Lim YA, et al.
    Parasit Vectors, 2015;8:341.
    PMID: 26104478 DOI: 10.1186/s13071-015-0956-5
    The morphotaxonomy of Rhipicephalus microplus complex has been challenged in the last few years and prompted many biologists to adopt a DNA-based method for distinguishing the members of this group. In the present study, we used a mitochondrial DNA analysis to characterise the genetic assemblages, population structure and dispersal pattern of R. microplus from Southeast Asia, the region where the species originated.
    Matched MeSH terms: DNA, Mitochondrial/genetics
  19. Phylogeny and evolution of the Drosophila nasuta subgroup based on mitochondrial ND4 and ND4L gene sequences
    Yu H, Wang W, Fang S, Zhang YP, Lin FJ, Geng ZC
    Mol Phylogenet Evol, 1999 Dec;13(3):556-65.
    PMID: 10620413
    The sequences of the mitochondrial ND4 gene (1339 bp) and the ND4L gene (290 bp) were determined for all the 14 extant taxa of the Drosophila nasuta subgroup. The average A + T content of ND4 genes is 76.5% and that of ND4L genes is 83.5%. A total of 114 variable sites were scored. The ND4 gene sequence divergence ranged from 0 to 5.4% within the subgroup. The substitution rate of the ND4 gene is about 1.25% per million years. The base substitution of the genes is strongly transition biased. Neighbor-joining and parsimony were used to construct a phylogeny based on the resultant sequence data set. According to these trees, five distinct mtDNA clades can be identified. D. niveifrons represents the most diverged lineage. D. sulfurigaster bilimbata and D. kepulauana form two independent lineages. The other two clades are the kohkoa complex and the albomicans complex. The kohkoa complex consists of D. sulfurigaster sulfurigaster, D. pulaua, D. kohkoa, and Taxon-F. The albomicans complex can be divided into two groups: D. nasuta, D. sulfurigaster neonasuta, D. sulfurigaster albostrigata, and D. albomicans from Chiangmai form one group; and D. pallidifrons, Taxon-I, Taxon-J, and D. albomicans from China form the other group. High genetic differentiation was found among D. albomicans populations. Based on our phylogenetic results, we hypothesize that D. niveifrons diverged first from the D. nasuta subgroup in Papua New Guinea about 3.5 Mya. The ancestral population spread to the north and when it reached Borneo, it diversified sequentially into the kohkoa complex, D. s. bilimbata, and D. kepulauana. About 1 Mya, another radiation occurred when the ancestral populations reached the Indo-China Peninsula, forming the albomicans complex. Discrepancy between morphological groupings and phylogenetic results suggests that the male morphological traits may not be orthologous.
    Matched MeSH terms: DNA, Mitochondrial/genetics*
  20. Genetic diversity of Asian water buffalo (Bubalus bubalis): mitochondrial DNA D-loop and cytochrome b sequence variation
    Lau CH, Drinkwater RD, Yusoff K, Tan SG, Hetzel DJ, Barker JS
    Anim. Genet., 1998 Aug;29(4):253-64.
    PMID: 9745663
    Swamp and river buffalo mitochondrial DNA (mtDNA) was sequenced for 303 bp of the cytochrome b gene for 54 animals from 14 populations, and for 158 bp of the D-loop region for 80 animals from 11 populations. Only one cytochrome b haplotype was found in river buffalo. Of the four haplotypes identified in swamp buffalo, one found in all populations is apparently ancestral both to the other swamp haplotypes and to the river haplotype. The phylogenetic relationships among the 33 D-loop haplotypes, with a cluster of 11 found in swamp buffalo only, also support the evolution of domesticated swamp and river buffalo from an ancestral swamp-like animal, most likely represented today by the wild Asian buffalo (Bubalus arnee). The time of divergence of the swamp and river types, estimated from the D-loop data, is 28,000 to 87,000 years ago. We hypothesise that the species originated in mainland south-east Asia, and that it spread north to China and west to the Indian subcontinent, where the rive type evolved and was domesticated. Following domestication in China, the domesticated swamp buffalo spread through two separate routes, through Taiwan and the Philippines to the eastern islands of Borneo and Sulawesi, and south through mainland south-east Asia and then to the western islands of Indonesia.
    Matched MeSH terms: DNA, Mitochondrial/chemistry*
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