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211.
212.
213.
Avise JC; Shapira JF; Daniel SW; Aquadro CF; Lansman RA 《Molecular biology and evolution》1983,1(1):38-56
We address the problem of the possible significance of biological
speciation to the magnitude and pattern of divergence of asexually
transmitted characters in bisexual species. The empirical data for this
report consist of restriction endonuclease site variability in maternally
transmitted mitochondrial DNA (mtDNA) isolated from 82 samples of
Peromyscus polionotus and P. leucopus collected from major portions of the
respective species' ranges. Data are analyzed together with previously
published information on P. maniculatus, a sibling species to polionotus.
Maps of restriction sites indicate that all of the variation observed can
be reasonably attributed to base substitutions leading to loss or gain of
particular recognition sites. Magnitude of mtDNA sequence divergence within
polionotus (maximum approximately equal to 2%) is roughly comparable to
that observed within any of five previously identified mtDNA assemblages in
maniculatus. Sequence divergence within leucopus (maximum approximately
equal to 4%) is somewhat greater than that within polionotus. Consideration
of probable evolutionary links among mtDNA restriction site maps allowed
estimation of matriarchal phylogenies within polionotus and leucopus.
Clustering algorithms and qualitative Wagner procedures were used to
generate phenograms and parsimony networks, respectively, for the
between-species comparisons. Three simple graphical models are presented to
illustrate some conceivable relationships of mtDNA differentiation to
speciation. In theoretical case I, each of two reproductively defined
species (A and B) is monophyletic in matriarchal genealogy; the common
female ancestor of either species can either predate or postdate the
speciation. In case II, neither species is monophyletic in matriarchal
genotype. In case III, species B is monophyletic but forms a subclade
within A which is thus paraphyletic with respect to B. The empirical
results for mtDNA in maniculatus and polionotus appear to conform closely
to case III. These theoretical and empirical considerations raise a number
of questions about the general relationship of the speciation process to
the evolution of uniparentally transmitted traits. Some of these
considerations are presented, and it is suggested that the distribution
patterns of mtDNA sequence variation within and among extant species should
be of considerable relevance to the particular demographies of speciation.
相似文献
214.
Accessing genetic diversity for crop improvement 总被引:1,自引:0,他引:1
215.
Developing taste buds in the anterior mandibular floor of perihatching
chicks were studied by high voltage electron microscopic autoradiography in
order to identify proliferating gemmal cell types. Montaged profiles of 29
taste buds in five cases euthanized between embryonic day 21 and
posthatching day 2 were analyzed after a single [3H]thymidine injection
administered on embryonic day 16, 17 or 18. Results showed that dark cells
comprised 55% of identified (n = 900 cells) and 62% of labeled (n = 568
cells) gemmal cells as compared with light, intermediate, basal or
perigemmal bud cells. Dark cells had both a greater (P < 0.05) number of
labeled cells and a greater amount of label (grains/nucleus) than the other
four bud cell types, irrespective of injection day. The nuclear area
(micron 2) of dark cells was not significantly larger (P > 0.05) than
that of the other gemmal cell types and therefore cannot account for the
greater amount for label in the dark cells. Interestingly, only dark cells
showed a positive correlation (P < 0.003) between amount of label and
nuclear area. Results suggest that, during the perihatching period of
robust cell proliferation, dividing dark cells may give rise primarily, but
not exclusively, to dark cell progeny.
相似文献
216.
217.
Amino acid sequence of locust neuroparsins 总被引:2,自引:0,他引:2
Neuroparsins A and B were isolated from the nervous part of the corpus cardiaca of Locusta migratoria via a two-step purification procedure. Both consist of two polypeptide chains linked by disulfide bridges. The N-terminal sequence of both native neuroparsins was determined: the N-terminal end of neuroparsin B was unique while that of neuroparsin A showed three different sequences. These sequences were that of neuroparsin B and two others having five and two extra N-terminal residues. Neuroparsin B was found as a homodimer and the complete sequence of the monomer, determined from peptide fragments generated by treatment with cyanogen bromide and endoprotease Glu-C, comprises 78 residues. 相似文献
218.
Amélie Zanetti Françoise Beauvais Jean-Claude Huet Jean-Claude Pernollet 《Planta》1992,187(2):163-170
In culture, Phytophthora fungi — except P. nicotianae — secrete proteins, called elicitins, which cause necrosis on the leaf of the non-host tobacco (Nicotiana tabacum L.) at a distance from the inoculation site, and are responsible for the incompatible reaction. Cryptogein and capsicein are elicitins secreted by P. cryptogea and P. capsici, respectively, and form part of a novel family of 10-kDa holoproteins. On tobacco, the necrotic activity of cryptogein is approx. 100-fold higher than that of capsicein. Using elicitins radioactively labelled in vivo, we have demonstrated that cryptogein and capsicein (i) move from a wound in the stem towards the leaves where they interact directly, (ii) reach their target without undergoing any molecular alteration, (iii) are carried in, and at the same rate as, the sap flow in the xylem, (iv) do not alter the rate of the xylem flow although they are able to provoke drastic damage to the lamina. Consequently, the remote necrotic activity of elicitins does not require any transportable secondary plant elicitor, so the differences in necrotic properties should be due to structural features involved in the interaction of elicitins with the leaf target cells.Abbreviations Mr
relative molecular mass
- RPLC
reversephase liquid chromatography
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
The authors are indebted to Mauricette Sallé-Tourné, Marc Sallantin and Christian Ouali for their skilful technical assistance. 相似文献
219.
220.
P. Touzet F. Riccardi C. Morin C. Damerval J. -C. Huet J. -C. Pernollet M. Zivy D. de Vienne 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1996,93(5-6):997-1005
This paper describes the first maize database of proteins separated by two-dimensional electrophoresis. Fifty-six coleoptile proteins and 18 leaf proteins from two maize lines were partially microsequenced. Thirty-six proteins (49%) displayed high similarity with database proteins. Nine of these proteins, representing five different functions, had never been described in maize. No conclusive function could be found for 45 polypeptides (61% of the microsequenced proteins). In addition, an alternative identification method, based on amino acid analysis, allowed candidates to be proposed for 17 proteins out of 44 additional proteins analyzed in the coleoptiles. These results are stored in a database which also includes, when available, genetic information about the chromosomal location of structural genes and regulatory factors of proteins. This database is being used in the context of a project on the genetic mapping of the expressed genome in maize. 相似文献