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91.
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
92.
Treatment with antithymocyte serum (ATS), prepared in burros or rabbits, significantly enhanced the antibody response to Type III pneumococcal polysaccharide (SSS-III) in 5 inbred and 2 hybrid strains of mice. The degree of enhancement attained depended upon the dose of ATS employed. Strains of mice differed with respect to the amount of enhancement produced following treatment with a given dose of the same preparation of ATS. 相似文献
93.
Spontaneous wasting disease in nude mice associated with Pneumocystis carinii infection 总被引:4,自引:0,他引:4
Several cases of wasting disease and dyspnea occurred in outbred Crl: CDI(ICR) nu/nu mice obtained recently from a commercial supplier. Gross necropsy revealed pulmonary consolidation, and histologically there was alveolar-wall thickening and filling of alveoli with macrophages and honey-combed eosinophilic material. Electron microscopic examination of lung tissue confirmed infection with Pneumocystis carinii. 相似文献
94.
Decline in suppressor T cell function with age in female NZB mice 总被引:38,自引:0,他引:38
95.
Further evidence for papovavirus as the probable etiology of transmissible lymphoma of Syrian hamsters 总被引:1,自引:0,他引:1
The role of hamster papovavirus as the etiology of transmissible lymphoma was investigated under strict conditions that prevented natural exposure to the lymphoma agent. In an initial experiment, 19 hamsters that were exposed naturally to transmissible lymphoma were placed in direct and indirect contact with weanling hamsters from an uninfected source. Lymphoma developed in the original infected hamsters as well as hamsters maintained in direct and indirect contact. In addition, one of the contact hamsters developed cutaneous epitheliomas, containing hamster papovavirus. Epithelioma homogenate was inoculated into primary hamster embryo cultures, in which hamster papovavirus replicated. Second and third passage tissue culture fluid containing hamster papovavirus induced lymphomas in suckling and weanling hamsters. Cell culture fluid from uninoculated embryo cultures was not oncogenic. 相似文献
96.
97.
Contamination of transplantable murine tumors with lymphocytic choriomeningitis virus 总被引:1,自引:0,他引:1
Lymphocytic choriomeningitis virus (LCMV) was isolated from a transplantable tumor after mice bearing the tumor began to die prematurely. Tumor lines, mice and laboratory personnel that had an association with the index laboratory were tested for LCMV infection. Testing of tumor lines from the index laboratory and four other laboratories revealed that 16 of 55 tumor samples used in vivo and one of eight tumor samples maintained in vitro were contaminated with LCMV. Laboratory personnel and uninoculated mice that were exposed to infected tumors had no LCMV antibody. The use of carefully monitored seed stocks is recommended to protect transplantable tumors that may be inadvertently contaminated by viruses. 相似文献
98.
Mammary tubular adenocarcinoma in a galago 总被引:1,自引:0,他引:1