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CO I (co + i)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Haplotype Frequency Distribution in Northeastern European Saduria entomon (Crustacea: Isopoda) Populations.

INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 6 2003
A Phylogeographic Approach
Abstract The distribution pattern of mtDNA haplotypes in distinct populations of the glacial relict crustacean Saduria entomon was examined to assess phylogeographic relationships among them. Populations from the Baltic, the White Sea and the Barents Sea were screened for mtDNA variation using PCR-based RFLP analysis of a 1150 bp fragment containing part of the CO I and CO II genes. Five mtDNA haplotypes were recorded. An analysis of geographical heterogeneity in haplotype frequency distributions revealed significant differences among populations. The isolated populations of S. entomon have diverged since the retreat of the last glaciation. The geographical pattern of variation is most likely the result of stochastic (founder effect, genetic drift) mechanisms and suggests that the haplotype differentiation observed is probably older than the isolation of the Baltic and Arctic seas. [source]

Analysis of mitochondrial DNA protein-coding region in the Yeso Sika deer (Cervus nippon yesoensis)

ANIMAL SCIENCE JOURNAL, Issue 4 2004
Kenta WADA
ABSTRACT In the present study, mitochondrial DNA sequences of the Yeso Sika deer (Cervus nippon yesoensis) were studied. Specifically, protein-coding genes as mitochondrial NADH dehydrogenase subunits (ND1, ND2, ND3, ND4L, ND4, ND5 and ND6), cytochrome c oxidase subunits (CO I and CO III), ATP synthase subunits (ATPase8 and ATPase6) and cytochrome b. Also, phylogenetic analyses on eight mammalian species were performed, including the Muntjac deer (Muntiacus reevesi). The rate of amino-acid substitution was lowest (3.74%) between Yeso Sika deer and Muntjac deer, and the values between Yeso Sika deer and other species (sheep, cattle, horse, pig, mouse, human and chimpanzee) were 6.63%, 7.30%, 12.55%, 13.03%, 23.59%, 24.82% and 25.04%, respectively. Among them, the highest value of divergence was recognized in ATPase8, and the second structure of ATPase8 showed a difference between the Yeso Sika deer and Muntjac deer as a result of the substitution of 34His,Tyr and 49Thr,Ile. In addition, we identified a substitution of an amino-acid sequence (19Thr,Ala) between the Yeso Sika deer and Yakushima Sika deer (C. n. yakushimae). From these results, ATPase8 was also a variable region in Cervidae. [source]

Deep genetic divergences among morphologically similar and parapatric Skistodiaptomus (Copepoda: Calanoida: Diaptomidae) challenge the hypothesis of Pleistocene speciation

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009
RYAN A. THUM
We used mitochondrial [cytochrome c oxidase subunit I (CO I), cytochrome b, and 16S] and nuclear [internal transcribed spacer (ITS) phylogenies of Skistodiaptomus copepods to test hypotheses of Pleistocene divergence and speciation within the genus. Mitochondrial (mt)DNA sequence divergences do not support hypotheses for Pleistocene speciation and instead suggest much more ancient speciation events in the genus. Skistodiaptomus oregonensis and Skistodiaptomus pygmaeus (i.e. two morphologically similar and parapatric species) exhibited uncorrected mtDNA sequence divergences exceeding 20%. Similarly, we identified three divergent clades of Skistodiaptomus pallidus that exhibited mtDNA sequence divergences exceeding 15%, suggesting that even intraspecific divergence within this morphospecies predates the Pleistocene. We found clear evidence of CO I pseudogenes in S. pygmaeus, but their presence did not lead to significant overestimates of sequence divergences for this gene. Substitution saturation and strong purifying selection have most likely led to underestimates of sequence divergences and divergence times among Skistodiaptomus. The widespread phenomenon of morphological stasis among genetically divergent copepod groups indicates that speciation often occurs with little or no morphological change. Instead, morphological evolution may occur idiosyncratically after speciation and create discordant patterns of morphological similarity, shared ancestry and divergence time. Cryptic species complexes are therefore common in copepods, and morphological species concepts underestimate their true species diversity. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 150,165. [source]

Disentangling causes of disjunction on the South Island of New Zealand: the Alpine fault hypothesis of vicariance revisited

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2007
MARTIN HAASE
Many elements of the flora and fauna of New Zealand's South Island show disjunct distributions with conspecific populations or closely-related species that occur in the north-west and south separated by a central gap. Three events have been implicated to account for this pattern: Pleistocene glaciations, Pliocene mountain building, or displacement along the Alpine fault, the border of the Pacific and Australian plates stretching diagonally across the South Island from south-west to north-east that formed during the Miocene. Disjunct distributions of species level taxa are probably too young to be due to Alpine fault vicariance. It has therefore been suggested that the biogeographical impact of the Alpine fault, if any, should be apparent on deeper phylogenetic levels. We tested this hypothesis by reconstructing the phylogenetic relationships of the hydrobiid gastropods of New Zealand based on mitochondrial DNA fragments of cytochrome oxidase subunit I (CO I) and 16S rDNA. The creno- and stygobiont species of this family are typically poor dispersers. Therefore, ancient patterns of distribution may be conserved. The phylogenetic reconstructions were in accordance with the Alpine fault hypothesis uniting genera occurring on either side of the fault. Divergence estimates based on a molecular clock of CO I indicated splits predating the Pliocene uplift of the Alps. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 361,374. [source]