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Molecular systematics and phylogeography of the gigantic earthworms of the Metaphire formosae species group (Clitellata, Megascolecidae) 总被引:1,自引:0,他引:1
The earthworms of the Metaphire formosae species group distributed in Taiwan are members of the Pheretima complex within the Megascolecidae. In this study, the systematics and phylogeography of this species group were investigated using DNA sequences of mitochondrial cytochrome c oxidase subunit I (COI), 16S ribosomal (r)RNA, and NADH dehydrogenase subunit 1 (ND1). The results indicated that the 13 taxa of the M. formosae species group form a clade, including a cryptic species discovered in this study. In addition, Metaphire hengchunensis (James, S.W., Shih, H.-T., Chang, H.-W., 2005. Seven new species of Amynthas (Clitellata: Megascolecidae) and new earthworm records from Taiwan. J. Nat. Hist. 39, 1007-1028) should be regarded as a subspecies of Metaphire paiwanna Tsai, C.-F., Shen, H.-P., Tsai, S.-C., 2000a. Native and exotic species of terrestrial earthworm (Oligochaeta) in Taiwan with reference to Northeast Asia. Zool. Stud. 39, 285-294, Tsai, C.-F., Tsai, S.-C., Liaw, G.-J., 2000b. Two new species of pontandric pheretimoid earthworms belonging to the genus Metaphire (Megascolecidae: Oligochaeta) from Taiwan. J. Nat. Hist. 34, 1731-1741, and Metaphire bununa glareosa Tsai et al. 2000 should be elevated to specific status. Phylogeographical inferences showed that allopatric speciation occurred in this species group during the rapid uplift of the main island of Taiwan between 5.0 and 2.5 million years ago. Our analysis exposes non-monophyly within each of the genera Amynthas and Metaphire, and more generally within the Pheretima complex. Further revisions of this speciose complex are urgently needed. 相似文献
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Members of the steroid hormone receptor superfamily interact with TFIIB (S300-II). 总被引:34,自引:0,他引:34
N H Ing J M Beekman S Y Tsai M J Tsai B W O'Malley 《The Journal of biological chemistry》1992,267(25):17617-17623
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The influence of self-complementary oligodeoxynucleotides on the chemical shifts of protons of the mutagenic acridine dye 9-aminoacridine has been measured. Upfield shifts indicative of intercalative binding are found in the cases of dG-dC, dC-dG, and dA-dT-dG-dC-dA-dT but not in dA-dT. Geometries for the complexes that are compatibile with the chemical-shift data and the X-ray structure of the complex between ri5C-rG and 9-aminoacridine determined by Sakore et al. [Sakore, T.D., Jain, S.C., Tsai, C., and Sobell, H.M. (1977), Proc. Natl. Acad. Sci. U.S.A. 74, 188--192] can be identified using recent theoretical estimates of shifts induced by nucleotide bases. 相似文献
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The 4S RNA genes in HeLa mitochondrial DNA (mtDNA) have been mapped by electron microscopy using the electron-opaque label ferritin. This method is based on the high affinity interaction between the protein, avidin, and biotin. 4S RNA, covalently coupled to biotin, was hybridized to single-stranded mtDNA. The hybrids were then labeled with ferritin-avidin conjugates. The positions of ferritin-labeled 4S RNA genes were determined relative to the rRNA genes on both heavy (H) and light (L) strands of mtDNA. This region was recognized as a duplex segment after hybridization either with rRNA in the case of H strands or with DNA complementary to rRNA in the case of L strands.Our studies suggest that at least nineteen 4S RNA genes are present in the HeLa mitochondrial genome. On the H strand, we have confirmed the nine map positions found in a previous electron microscope mapping study (Wu et al., 1972) and obtained evidence for three additional 4S RNA genes. On the L strand, seven 4S RNA genes have been mapped. The nineteen genes are distributed more or less uniformly around the genome. There is a pair of closely spaced genes, approximately 150 nucleotides apart, on the H strand, and another closely spaced pair on the L strand. 相似文献
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Formation and stability of the 5 S RNA transcription complex 总被引:49,自引:0,他引:49
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Differential transcription of Xenopus oocyte and somatic-type 5 S genes in a Xenopus oocyte extract 总被引:10,自引:0,他引:10
L Millstein P Eversole-Cire J Blanco J M Gottesfeld 《The Journal of biological chemistry》1987,262(35):17100-17110
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While this sequence shares a significant homology with the 5S RNAs of other archaebacteria and is consistent with current models for the secondary structure of 5S RNAs, it contains three unusual features. The G + C content (72-74%) is significantly higher than other 5S RNAs; the secondary structure is distinguished by unusually stable and extended helical structures and, most important, there is evidence for sequence heterogeneity in the form of complementary base substitutions and precursor processing. This supports recent evidence (Newmann, H., Gierl, A., Tu, J., Leibrock, J., Staiger, D. and Zillig, W. (1983) Mol. Gen. Genet. 192, 66-72) that, like many of the higher eukaryotes, this group of sulphur-metabolizing bacteria may contain multiple 5S RNA genes. 相似文献
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Goats and some sheep synthesize a juvenile hemoglobin, Hb C (alpha 2 beta
C2), at birth and produce this hemoglobin exclusively during severe anemia.
Sheep that synthesize this juvenile hemoglobin are of the A haplotype.
Other sheep, belonging to a separate group, the B haplotype, do not
synthesize hemoglobin C and during anemia continue to produce their adult
hemoglobin. To understand the basis for this difference we have determined
the structural organization of the beta- globin locus of B-type sheep by
constructing and isolating overlapping genomic clones. These clones have
allowed us to establish the linkage map 5' epsilon I-epsilon II-psi beta
I-beta B-epsilon III-epsilon IV- psi beta II-beta F3' in this haplotype.
Thus, B sheep lack four genes, including the BC gene, and have only eight
genes, compared with the 12 found in the goat globin locus. The goat
beta-globin locus is as follows: 5' epsilon I-epsilon II-psi beta X-beta
C-epsilon III-epsilon IV-psi beta Z-beta A-epsilon V-epsilon VI-psi beta
Y-beta F3'. Southern blot analysis of A-type sheep reveals that these
animals have a beta- globin locus similar to that of goat, i.e., 12 globin
genes. Thus, the beta-globin locus of B-haplotype sheep resembles that of
cows and may have retained the duplicated locus of the ancestor of cows and
sheep. Alternatively, the B-sheep locus arrangement may be the result of a
deletion of a four-gene set from the triplicated locus.
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