共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
Michael J. Wade 《Evolution; international journal of organic evolution》1990,44(8):2004-2011
The norm of reaction, the set of average phenotypes produced by a genotype in different environments, can be affected by spatial variation in natural selection especially when there exists genotype-environment interaction. In subdivided populations, the greater the genotype-environment interaction variance and the lower the migration rate, the more independent are the possible evolutionary trajectories for local adaptation. I examined genotype-environment interaction in the rate of population increase for lineages randomly derived from a wild population of Tribolium castaneum across a series of ecologically important environments. The lineages were derived from an outbred, wild-caught population by 14 generations of random genetic drift, during which the effective size of each lineage was approximately 22 breeding adults. The environments studied were the classic temperate-wet and cold-dry climates of Park (1954) in factorial combination with two genetic strains of a congeneric competitor, T. confusum. Much among-lineage genetic variation for rate of population increase was found for each of these ecologically important environments of climate and competition. Genotype-environment interaction accounted for 40.5% of the total among-lineage variance in rate of population increase signifying that the performance of a lineage in one environment is not necessarily a good predictor of its performance in another. Changing the genetic identity of the competitor changed the rate of increase of some lineages as much or more than changing the climatic conditions of temperature and humidity. This is the first empirical study to characterize the genotype-environment interaction variance associated with genetic variation in a competing congeneric species. This competitor-specific genetic variation in competitive ability may play an important role in coevolution in subdivided populations. 相似文献
4.
5.
6.
THE EVOLUTION OF AGRICULTURE IN BEETLES (CURCULIONIDAE: SCOLYTINAE AND PLATYPODINAE) 总被引:6,自引:0,他引:6
Brian D. Farrell Andrea S. Sequeira Brian C. O'Meara Benjamin B. Normark Jeffrey H. Chung Bjarte H. Jordal 《Evolution; international journal of organic evolution》2001,55(10):2011-2027
Abstract Beetles in the weevil subfamilies Scolytinae and Platypodinae are unusual in that they burrow as adults inside trees for feeding and oviposition. Some of these beetles are known as ambrosia beetles for their obligate mutualisms with asexual fungi—known as ambrosia fungi—that are derived from plant pathogens in the ascomycete group known as the ophiostomatoid fungi. Other beetles in these subfamilies are known as bark beetles and are associated with free‐living, pathogenic ophiostomatoid fungi that facilitate beetle attack of phloem of trees with resin defenses. Using DNA sequences from six genes, including both copies of the nuclear gene encoding enolase, we performed a molecular phylogenetic study of bark and ambrosia beetles across these two subfamilies to establish the rate and direction of changes in life histories and their consequences for diversification. The ambrosia beetle habits have evolved repeatedly and are unreversed. The subfamily Platypodinae is derived from within the Scolytinae, near the tribe Scolytini. Comparison of the molecular branch lengths of ambrosia beetles and ambrosia fungi reveals a strong correlation, which a fungal molecular clock suggests spans 60 to 21 million years. Bark beetles have shifted from ancestral association with conifers to angiosperms and back again several times. Each shift to angiosperms is associated with elevated diversity, whereas the reverse shifts to conifers are associated with lowered diversity. The unusual habit of adult burrowing likely facilitated the diversification of these beetle‐fungus associations, enabling them to use the biomass‐rich resource that trees represent and set the stage for at least one origin of eusociality. 相似文献
7.
8.
9.
Michael J. Wade 《Evolution; international journal of organic evolution》1991,45(7):1574-1584
The genetic and ecological effects of population subdividsion were investigated for two wild strains of Tribolium castaneum and two wild strains of T. confusum and compared with the effects of population subdivision on the synthetic laboratory strain of T. castaneum (c-SM), used extensively in earlier experiments. For the c-SM strain, it has been shown repeatedly, for a variety of different population structures (different combinations of effective numbers, Ne, and migration rates, m), that large heritable differences in population growth rate arise among demes during 10 to 15 generations of population subdivision. Because this laboratory strain was synthesized by mass mating several “inbred” strains in 1973 (80 to 100 generations ago), it is possible that it has genetic variation for fitness (measured as the heritable variance among demes in the rate of population increase) unusually large compared to natural populations of flour beetles. In this paper, I report that natural populations of flour beetle exhibit as much or more phenotypic and genetic variation in the effects of population structure on fitness than the laboratory strain, c-SM. The observation of substantial heritable variation for fitness in natural populations is unexpected under additive theory and may be indicative of nonadditive genetic variance. 相似文献
10.
11.
The genus Tribolium Desv. consists of nine species, i.e., T. utriculosum (Nees) Renv., T. ciliare (Stapf) Renv., T. echinatum (Thunb.) Desv., T. hispidum (Thunb.) Desv., T. acutiflorum (Nees) Renv., T. obliterum sensu Davidse, T. glomeratum sensu Davidse, T. uniolae (L.f.) Renv., and T. brachystachyum (Nees) Renv. The genus has a basic chromosome number of 6, and from diploid to hexaploid specimens have been examined. Precocious segregation of metaphase I bivalents were observed in four species. Multivalent formation results in unequal chromosome segregation during anaphase I, and several cells with an 11–13 chromosome distribution have been observed. The presence of univalents and anaphase I bridges in all T. brachystachyum specimens suggests a hybrid origin for the species. B-chromosomes were present in specimens from four species. The B-chromosomes are similar to the euchromosomes with the exception that they do not participate in meiosis. The B-chromosomes have a possible isochromosome origin. The cytogenetic evidence presented supports the combination of Plagiochloa and Lasiochloa into Tribolium and indicates that the genus is closely related to Urochlaena, whereas it is not closely related to Prionanthium. 相似文献
12.
中国麻黄属的地理分布与演化 总被引:8,自引:0,他引:8
中国现有麻黄属植物15种,2变种和1变型,这些种属于膜果麻黄组和麻黄组中的麻黄亚组,没有原始类型藤麻黄亚组的代表。我国除长江中下游及珠江流域的省区处,其他省区都有分布。麻黄花粉的化石-麻分在地层中的分布说明,麻黄在过去曾遍布我国各地,发现的最早时期是在侏罗纪,到白垩纪-早第三纪时,种类较现在丰富,将近50种,根据麻黄粉在世界各地地层中的分布和时期,结合大陆飘移和海底扩张板块构造学说推断,原麻黄在各 相似文献
13.
14.
15.
16.
Richard Gomulkiewicz Mark Kirkpatrick 《Evolution; international journal of organic evolution》1992,46(2):390-411
We extend methods of quantitative genetics to studies of the evolution of reaction norms defined over continuous environments. Our models consider both spatial variation (hard and soft selection) and temporal variation (within a generation and between generations). These different forms of environmental variation can produce different evolutionary trajectories even when they favor the same optimal reaction norm. When genetic constraints limit the types of evolutionary changes available to a reaction norm, different forms of environmental variation can also produce different evolutionary equilibria. The methods and models presented here provide a framework in which empiricists may determine whether a reaction norm is optimal and, if it is not, to evaluate hypotheses for why it is not. 相似文献
17.
18.
Norman C. Duke John A. H. Benzie John A. Goodall Elizabeth R. Ballment 《Evolution; international journal of organic evolution》1998,52(6):1612-1626
Allozyme variation in species of the mangrove genus Avicennia was screened in 25 populations collected from 22 locations in the Indo-West Pacific and eastern North America using 11 loci. Several fixed gene differences supported the specific status of Avicennia alba, A. integra, A. marina, and A. rumphiana from the Indo-West Pacific, and A. germinans from the Atlantic-East Pacific. The three varieties of A. marina, var. marina, var. eucalyptifolia, and van australasica, had higher genetic similarities (Nei's I) and no fixed gene differences, confirming their conspecific status. Strong genetic structuring was observed in A. marina, with sharp changes in gene frequencies at the geographical margins of varietal distributions. The occurrence of alleles found otherwise in only one variety, in only immediately adjacent populations of another variety, provided evidence of introgession between varieties. The varieties appear to have diverged recently in the Pleistocene and are apparently not of ancient Cretaceous origin, as suggested earlier. Despite evidence of high degrees of outcrossing, gene flow among populations was relatively low (Nem < 1–2), except where populations were geographically continuous, questioning assumptions that these widespread mangrove species achieve high levels of long-distance dispersal. 相似文献
19.
William R. Atchley 《Evolution; international journal of organic evolution》1987,41(2):316-330
A model is presented which permits integration of developmental information into genetic discussions about evolutionary change in morphology. Development of a trait is described in terms of an ontogenetic trajectory whose properties are defined by a small number of parameters. Some evolutionary aspects of development are examined from the perspective of this quantitative genetic model. Particular attention is given to the developmental origin of pleiotropic effects, developmental constraints, heterochrony, and the growth and morphogenesis of complex morphologies. The role of genetic maternal effects in mammalian development is briefly examined, particularly as it relates to selection on developmental traits. 相似文献