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1.
Chloroplast DNA phylogeography of Alnus glutinosa (L.) Gaertn. 总被引：8，自引：0，他引：8
Traditionally, information on the postglacial history of plant species has been gained from the analysis of fossil pollen data. More recently, surveys of present patterns of genetic variation have given valuable insights into species phylogeography. The genus Alnus , based on fossil data, is known to have had at least four glacial refugia. A survey of chloroplast DNA (cpDNA) diversity in populations of black alder ( A. glutinosa ) was undertaken in order to gain more insight into its postglacial history. This revealed a high degree of structuring of 13 cpDNA haplotypes on a European scale which indicated that most of northern and central Europe was colonized from a refuge in the Carpathian Mountains. Based on the distribution of two common cpDNA haplotypes, colonization routes from this refuge can be determined. The locations of other previously identified refugia are confirmed and two formerly unconfirmed refugial areas for alder (southern Spain and Turkey) are proposed. 相似文献
2.
Variation in the chloroplast genome of Ilex aquifolium (English holly), a dioecious evergreen tree native to south, west and central Europe, was analysed using polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLPs) and microsatellites. Differentiation between populations was high (GST = 0.595) and evidence for phylogeographical structure was detected (NST = 0.697, significantly higher than GST). Two chloroplast lineages were inferred originating from putative glacial refugia in southern Europe (Iberia, Italy and possibly the Balkans). The GST value was higher than reported for endozoochorous hermaphrodite species and for anemochorous dioecious species investigated over a similar geographical scale. It appears that dioecy has contributed to strong differentiation between refugia and that this has been maintained following postglacial recolonization as a result of limited seed flow. Palynological records for I. aquifolium are poor, thus these results give an important insight into patterns of glacial isolation and postglacial recolonization of this species. 相似文献
3.
Variation in the chloroplast genome of Calluna vulgaris (heather), the dominant species of northwest European heath communities, was analysed using polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLPs) and microsatellites. No length polymorphisms were detected in the 100-200 base pair (bp) fragments amplified by the conserved microsatellite primers, and sequencing revealed that the repeat regions were interrupted relative to the corresponding sequence in Nicotiana tabacum. In contrast, PCR-RFLP analysis revealed high levels of haplotype diversity within populations (hS = 0.443, hT = 0.842), as well as substantial differentiation between populations (GST = 0.473). Diversity and differentiation were higher in southern Europe than in northern Europe. Interpreted in the light of data from allozyme studies and pollen core records, the results suggest that the main glacial refugia for C. vulgaris were located in southwest Europe, including northern Spain, the Pyrenees and the Massif Central region of France. There is also evidence for diffuse survival of the species at more northerly latitudes. 相似文献
4.
The distribution of haplotypic diversity of 38 European chestnut (Castanea sativa Mill.) populations was investigated by PCR/RFLP analysis of regions of the chloroplast and mitochondrial genomes in order to shed light on the history of this heavily managed species. The rapid expansion of chestnut starting from 3000 years ago is strongly related to human activities such as agricultural practice. This demonstrates the importance of human impact, which lasted some thousands of years, on the present-day distribution of the species. No polymorphism was detected for the single mitochondrial analysed region, while a total of 11 different chloroplast (cp) haplotypes were scored. The distribution of the cpDNA haplotypes revealed low geographical structure of the genetic diversity. The value of population subdivision, as measured by GSTc, is strikingly lower than in the other species of the family Fagaceae investigated. The actual distribution of haplotypic diversity may be explained by the strong human impact on this species, particularly during the Roman civilization of the continent, and to the long period of cultivation experienced during the last thousand years. 相似文献
5.
IVANA SHEHLIK J. JAKOB SCHNELLER fls KONRAD BACHMANN 《Biological journal of the Linnean Society. Linnean Society of London》2002,77(1):87-103
It has been hypothesized that the subalpine Erinus alpinus survived the Pleistocene glaciation in southern French refugia peripheral to the Alps and postglacially immigrated to its northern Alpine distribution (tabula rasa hypothesis). However, E. alpinus is also known from nunataks in the northern Prealps. PCR–RFLP of the cpDNA revealed no variation, whereas AFLPs identified three phylogeographical groups among the 22 populations: (1) a central Swiss group, (2) a single central Swiss population on Mount Rigi, and (3) all other populations located to the west and east of the central Swiss group (west-eastern populations). The population representing the putative French refugium was not distinct from the west-eastern populations but was different from the populations of central Switzerland. We consider this support for locally restricted in situ survival of E. alpinus in the northern Prealps or nearby Jura mountains (dating back to 60–28 ky BP). However, the west-eastern gene-pool probably immigrated postglacially from southern France through the prealpine lowlands (not before 14.6 kyr BP), skirting central Switzerland. The near-absence of gene flow among the central Swiss and the west-eastern populations may be the reason why these historical genetic patterns are still detectable. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 77, 87–103. 相似文献
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Koskinen MT Ranta E Piironen J Veselov A Titov S Haugen TO Nilsson J Carlstein M Primmer CR 《Molecular ecology》2000,9(10):1609-1624
In stark contrast to other species within the Salmonidae family, phylogeographic information on European grayling, Thymallus thymallus, is virtually nonexistent. In this paper, we utilized mitochondrial DNA polymerase chain reaction-restriction fragment length polymorphism (mtDNA PCR-RFLP) and sequence variation to infer the postglacial dispersal routes of T. thymallus into and within northern Europe, and to locate geographically, potential evolutionarily distinct populations. Mitochondrial analyses revealed a total of 27 T. thymallus haplotypes which clustered into three distinct lineages. Average pairwise interlineage divergence was four and nine times higher than average intralineage divergence for RFLP and sequence data, respectively. Two European grayling individuals from the easternmost sample in Russia exhibited haplotypes more genetically diverged from any T. thymallus haplotype than T. arcticus haplotype, and suggested that hybridization/introgression zone of these two sister species may extend much further west than previously thought. Geographic division of the lineages was generally very clear with northern Europe comprising of two genetically differentiated areas: (i) Finland, Estonia and north-western Russia; and (ii) central Germany, Poland and western Fennoscandia. Average interpopulation divergence in North European T. thymallus was 10 times higher than that observed in a recent mtDNA study of North American T. arcticus. We conclude that (i) North European T. thymallus populations have survived dramatic Pleistocene temperature oscillations and originate from ancient eastern and central European refugia; (ii) genetic divergence of population groups within northern Europe is substantial and geographically distinct; and (iii) the remainder of Europe harbours additional differentiated assemblages that likely descend from a Danubian refugium. These findings should provide useful information for developing appropriate conservation strategies for European grayling and exemplify a case with a clear need for multinational co-operation for managing and conserving biodiversity. 相似文献
7.
JEAN-MICHEL LEONG POCK TSY ROSELYNE LUMARET† DIANA MAYNE‡ ABDALLAHI OULD MOHAMED VALL§ YAHIA I. M. ABUTABA¶ MAURICE SAGNA SOAHARIN'NY ONY RAKOTONDRALAMBO RAOSETA PASCAL DANTHU 《Molecular ecology》2009,18(8):1707-1715
The African baobab ( Adansonia digitata L.) is an emblematic, culturally important, and physically huge tropical tree species whose natural geographical distribution comprises most of tropical Africa, but also small patches of southern Arabia, and several Atlantic and Indian Ocean islands surrounding the African continent, notably including Madagascar. We analysed the polymerase chain reaction–restriction fragment length polymorphism of five chloroplast DNA fragments obtained from 344 individuals of A. digitata collected from 74 populations covering the entire extant distribution range of the species. Our goal was to reconstruct the phylogeographical history of the species and, if possible, to identify its centre of origin, which has been a subject of controversy for many decades. We identified five haplotypes whose distribution is clearly geographically structured. Using several species of Adansonia and of closely related genera as outgroups, the haplotypes showed a clear phylogeographical pattern of three groups. Two are phylogenetically related to the outgroup taxa, and are distributed in West Africa. The third group is substantially more differentiated genetically from outgroup species, and it corresponds to southern and eastern Africa, Arabia and the Indian Ocean islands, including Madagascar. According to our results, the tetraploid A. digitata , or its diploid progenitor, probably originated in West Africa and migrated subsequently throughout the tropical parts of that continent, and beyond, by natural and human-mediated terrestrial and overseas dispersal. 相似文献
8.
Balloux F 《Evolution; international journal of organic evolution》2004,58(9):1891-1900
It has been proposed that effective size could be estimated in small dioecious population by considering the heterozygote excess observed at neutral markers. When the number of breeders is small, allelic frequencies in males and females will slightly differ due to binomial sampling error. However, this excess of heterozygotes is not generated by dioecy but by the absence of individuals produced through selfing. Consequently, the approach can also be applied to self-incompatible monoecious species. Some inaccuracies in earlier equations expressing effective size as function of the heterozygote excess are also corrected in this paper. The approach is then extended to subdivided populations, where time of sampling becomes crucial. When adults are sampled, the effective size of the entire population can be estimated, whereas when juveniles are sampled, the average effective number of breeders per subpopulations can be estimated. The main limitation of the heterozygote excess method is that it will only perform satisfactorily for populations with a small number of reproducing individuals. While this situation is unlikely to happen frequently at the scale of the entire population, structured populations with small subpopulations are likely to be common. The estimation of the average number of breeders per subpopulations is thus expected to be applicable to many natural populations. The approach is straightforward to compute and independent of equilibrium assumptions. Applications to simulated data suggest the estimation of the number of breeders to be robust to mutation and migration rates, and to specificities of the mating system. 相似文献
9.
European hedgehogs, Erinaceus europaeus and E. concolor, are among the many European plant and animal taxa that have been subjected to cyclical restriction to glacial refugia and interglacial expansion. An analysis of 95 mitotypes, comprising partial cytochrome b and control region sequences, shows deep divergence between the two hedgehog species. Three europaeus and two concolor clades are clearly identified and are consistent with previously identified refugia for Europe: the Iberian peninsula, Italy, and the Balkans. The degree of mitochondrial divergence among these clades suggests pre-Pleistocene separation of the refugial populations. In contrast, analysis of two nuclear introns clearly separates the two concolor clades, as in the mitochondrial data, but cannot discriminate the three europaeus clades. This discrepancy between nuclear and mitochondrial data is attributed to historical differences in the refugial population size of europaeus and concolor. The geographical distribution of mitotypes is analysed using nested clade analysis. This method, by including unobserved ('missing') mitotypes, can identify mitotype groupings that remain undetected in conventional analyses. However, the application of nested clade analysis to the study of refugial populations may be hampered by such factors as the loss of haplotypes from the refugial areas by repeated contractions of the population and the recent time scale of colonization relative to mutation rate. 相似文献
10.
Isolation and characterization of 11 microsatellite markers from Sagittaria latifolia (Alismataceae)
We developed 11 microsatellite loci for Sagittaria latifolia, an aquatic plant common to wetlands of North America. From an (AG)-enriched library, we identified 66 unique microsatellite sequences for which primers could be designed. Twenty-two loci reliably amplified a clear single band of expected size, and 11 loci were scoreable and polymorphic. For these 11 loci, we genotyped a monoecious and a dioecious population, yielding four to 14 alleles per locus. Three loci exhibited significant linkage disequilibrium leaving eight independent variable loci. Eight loci also amplified in four other Sagittaria species. These microsatellite loci will be useful to compare genetic structure among monoecious and dioecious populations of S. latifolia. 相似文献
11.
Microsatellite and mitochondrial DNA (mtDNA) variability data were used to study outbreaks of Mediterranean fruit fly in California in the years 1992-94 and 1997-99. A total of 359 flies caught in monitoring traps during these years were examined at three polymorphic mtDNA restriction sites and two microsatellite loci. Composite genotypes obtained through analysis of these markers indicate at least five independent introductions of medflies into California between 1992 and 1998. Whereas the majority of specimens displayed a single mtDNA haplotype (AAA), variation of microsatellite alleles among these flies suggests at least one additional introduction in 1993 into southern California. Flies displaying the AAB haplotype sampled in 1992 both in northern and southern California shared microsatellite alleles absent in AAA flies although lacking others commonly found in AAA specimens, thus supporting the hypothesis of an independent introduction of these flies from a different source. In contrast to earlier infestations, a few specimens caught in southern California in 1993 and again in 1998 showed both mtDNA and microsatellite patterns consistent with a Hawaiian origin. Single flies collected in Santa Clara County in 1997 and in El Monte, Los Angeles County & in 1999 most likely represent a sixth and seventh distinct introduction, respectively. 相似文献
12.
Unisexual flowers have evolved repeatedly in the angiosperms. In Poaceae, multiple transitions from bisexual to unisexual flowers are hypothesized. There appear to be at least three distinct developmental mechanisms for unisexual flower formation as found in members of three subfamilies (Ehrhartoideae, Panicoideae, Pharoideae). In this study, unisexual flower development is described for the first time in subfamily Chloridoideae, as exemplified by Bouteloua dimorpha. Scanning electron microscopy (SEM) and anatomy were used to characterize the development of male (staminate) and female (pistillate) flowers, spikelets, and inflorescences. We found the developmental pathway for staminate flowers in B. dimorpha to be distinct from that described in the other three subfamilies, showing gynoecial arrest occurs at a different stage with possible loss of some cellular contents. However, pistillate flowers of B. dimorpha had some similarity to those described in other unisexual-flowered grasses, with filament and anther differentiation in abortive stamens. Comparing our findings with previous reports, unisexual flowers seem to have evolved independently in the four examined grass subfamilies. This analysis suggests the action of different genetic mechanisms, which are consistent with previous observations that floral unisexuality is a homoplasious condition in angiosperms. 相似文献
13.
D. Ahmad A. Kikuchi S.A. Jatoi M. Mimura & K.N. Watanabe 《The Annals of applied biology》2009,155(1):91-101
We examined genetic variation in 22 accessions belonging to 11 species in four genera of the Zingiberaceae, mainly from Myanmar, by PCR–restriction fragment length polymorphism analysis to investigate their relationships within this family. Two of 10 chloroplast gene regions ( trnS-trnfM and trnK2 – trnQr ) showed differential PCR amplification across the taxa. Restriction enzyme digestion of the PCR products revealed interspecific variability. The restriction patterns were used to classify the regions as either highly conserved or variable across the taxa. None of the regions was highly conserved across the four genera, and the level of conservation varied. The gene region trnS-trnfM appeared to display interspecific variability among most of the species. However, the relative efficiency of different restriction enzymes depended on the gene regions and genera investigated. Cluster analysis revealed interspecific discrimination among the taxa. The two Curcuma species ( Curcuma zedoaria and Curcuma xanthorrhiza ) appeared to be identical, thus supporting their recent classification as synonyms. The results provide the basis for selecting specific combinations of restriction enzymes and gene regions of chloroplast DNA (cpDNA) to identify interspecific variation in the Zingiberaceae and to identify both highly conserved and variable regions. Overall, cpDNA depicted comparatively diverse genetic profile of the studied germplasm. The genetic information revealed here can be applied to the conservation and future breeding of Zingiber and Curcuma species. 相似文献
14.
JOHN R. PANNELL DARREN J. OBBARD RICHARD J. A. BUGGS 《Biological journal of the Linnean Society. Linnean Society of London》2004,82(4):547-560
The evolutionary success of polyploidy most directly requires the ability of polyploid individuals to reproduce and transmit their genes to subsequent generations. As a result, the sexual system (i.e. the mating system and the sex allocation of a species) will necessarily play a key role in determining the fate of a new polyploid lineage. The effects of the sexual system on the evolution of polyploidy are complex and interactive. They include both aspects of the genetic system, the genetic load maintained in a population and the ecological context in which selection takes place. Here, we explore these complexities and review the empirical evidence for several potentially important genetic and ecological interactions between ploidy and the sexual system in plants. We place particular emphasis on work in our laboratory on the European annual plant Mercurialis annua , which offers promising scope for detailed investigations on this topic. M. annua forms a polyploid complex that varies in its sexual system from dioecy (separate sexes) through androdioecy (males and hermaphrodites) to functional hermaphroditism. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 82 , 547–560. 相似文献
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Ploidy levels were analyzed in 21 European populations of the Arenaria ciliata complex using baseline chromosome counts derived from Feulgen staining of HCl‐treated shoot meristems and calibrated flow‐cytometry analysis of fresh and archival frozen tissue. Calibration with two to three control samples of different ploidy facilitated rapid identification of ploidy states in unknown samples. Observed ploidy levels varied from 2N = 40–200, with the majority of populations showing 2N = 40–80. High‐altitude populations collectively showed the full range of ploidy states, but at low elevations only lower ploidy levels were observed. Populations with the highest observed ploidy contained the greatest observed phylogenetic diversity in the western and eastern Alps. Multiple polyploidization events are inferred in the continental European metapopulation, with lower, more stable ploidy characteristic of the west and north. The method deployed provides an effective approach to ploidy analysis for archival desiccated/frozen tissue samples from biogeographic collections. 相似文献
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Unlike the seriate lowland rain forests in SE Asia, the tropical vegetation of Xishuangbanna (SW China) has developed in habitats with comparatively lower temperatures and precipitation. Consequently, although most of the families and genera of the flora are components of tropical ecosystems, many have reached their distribution limits in latitude. Selection pressures on sexual systems in these environments may be different from that experienced in lowland tropical regions. Here, we examine the sexual systems of 685 species of flowering plants belonging to 109 families and 356 genera based on 42 plots with a total area of 15.4 ha and compare our results with surveys of sexual systems from other tropical ecosystems. Among these species, 60.6 percent were hermaphroditic, 14.3 percent were monoecious, and 25.1 percent were dioecious. The percentage of dioecious sexual system among tree species (26.1%) was similar or higher than that of other tropical tree floras. Monoecy was significantly associated with the tree growth form and was relatively common in seasonal forest vegetation. Sexual systems involving unisexual flowers (dicliny) are particularly well represented in the tropical forests of Xishuangbanna accounting for 39.4 percent of all species surveyed. This pattern may be associated with the prevalence of relatively small inconspicuous flowers in the tropical forests of SE Asia and their correlation with diclinous sexual systems generally. 相似文献
20.
Natural selection is presumed to be the driving force behind the occurrence of phenotypically and genetically divergent populations in sympatry within many north temperate freshwater fishes. If, however, these populations have different ancestral origins, history could also contribute to their divergence. We previously found evidence for the role of selection in the evolution of divergent outflow and inflow breeding populations of migratory brook charr (Salvelinus fontinalis) inhabiting postglacial Mistassini Lake (Quebec, Canada). Here, we show that these populations do not have a common origin, through the use of admixture and spatial analyses with seven microsatellite loci. Divergent populations clustered into two different population groups when compared to samples from surrounding drainages, although inflow populations appeared to be more admixed between the two population groups than the outflow population. These results are noteworthy since outflow and inflow populations were monomorphic at mitochondrial DNA (338-bp sequence of the control region) and are only moderately differentiated (mean F(ST) = 0.10). Colonization by two ancestral populations was also consistent with known outflow direction changes throughout lake formation. In addition to providing insight into how phenotypic divergence in sympatry may have been affected by the nature (i.e. timing and direction) of colonization of ancestral populations, our results also suggest that ancestral populations may have differed in their ability to colonize certain lake habitats. 相似文献