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1.
The endangered herb Kirengeshoma palmata, from eastern Asia, has had its population severely reduced in number through habitat loss and fragmentation. All of the
individuals within five subgroups at Mt. Baek-un-san, in the southern part of Korea, were genetically surveyed by allozyme
analysis. Genetic diversity levels within subgroups were relatively high, and a consistently high outcrossing rate as well
as a negligible biparental mating rate were confirmed by this study. Several groups of visibly connected ramets were observed
in a clustered distribution which suggested cloning. Absence of mating partner rather than pollinators decreased seed production
in small mating groups. The present genetic structure of the five subgroups was probably the result of local extinction of
intervening populations. Because K. palmata may be a self-incompatible species, populations with few genets face lowered seed set due to mate scarcity. Thus, this type
of population may be at an increased risk of extinction as a result of inbreeding depression, loss of genetic variability,
and reduced sexual reproduction. The small, genetically depauperate subgroups may need an input of seeds or plants from other
populations in China or Japan in order to regenerate, but the possibility of outcrossing depression leads us to recommend
outbreeding among the local subgroups of Mt. Baek-un-san to restore genetic variability. 相似文献
2.
We developed 11 polymorphic microsatellite markers for an endangered shrub Ammopiptanthus mongolicus using the Fast Isolation by AFLP of Sequences Containing repeats protocol. Polymorphism of each locus was assessed in 24
individuals from five natural populations of A. mongolicus. The average allele number of these markers was 4.2, ranging from 2 to 7. The observed (H
O) and expected (H
E) heterozygosities were 0.044–0.956 and 0.044–0.827, respectively. Further assessment in the congeneric species A. nanus revealed that nine of eleven loci were successfully amplified, but only two loci showed polymorphism. These markers provide
powerful tools for the conservation genetics studies of A. mongolicus. 相似文献
3.
In vitro propagation of Rhododendron ponticum L. subsp. baeticum, an endangered species present in limited and vulnerable populations as a Tertiary relict in the southern Iberian Peninsula, was attained. Several cytokinin:IAA ratios and a range of zeatin concentrations were evaluated for their effect on shoot multiplication from apical shoots and nodal segments. The type of cytokinin and the origin of the explant were the most important factors affecting shoot multiplication. The highest shoot multiplication rate was obtained from single-nodal explants on medium supplemented with zeatin. Increasing zeatin concentration promotes shoot multiplication independently of explant type, although this effect tends to decrease with higher zeatin concentration. Shoot growth was higher in apical shoots and it was not stimulated by the presence of auxin. A number of experiments were conducted to identify suitable procedures for rooting of in vitro produced shoots. The best results in terms of in vitro rooting were obtained with Andersons modified medium with macrosalts reduced to one-half, regardless of the auxin or its concentration in the medium. Although rooting frequency rose to 97% by basal immersion of shoots in auxin concentrated solution followed by in vitro culture on an auxin-free medium, the survival of the plants after 6 months of acclimatization was poor (50%). Best results (100% rooting and survival) were observed for ex vitro rooting. The micropropagated plants from this study were successfully reintroduced into their natural habitat (87% of survival after 8 months). 相似文献
4.
5.
Ranunculus nipponicus (Makino) Nakai is a vulnerable aquatic macrophyte in the Kinki district, which is the southernmost distribution of this species
in Japan. The genetic diversity and structure within and among eleven extant populations were assessed using the inter-simple
sequence repeats (ISSR) polymerase chain reaction in association with combinations of propagation pattern (clonal and/or seeds)
and genotypic geographical structure. In total, 53 bands were amplified, of which 18 (34%) were polymorphic. Analysis of the
ISSR bands identified 46 genotypes among 81 individuals from one stream population and 72 distinct genotypes among 147 individuals
in the Kinki district. An unweighted pair group method with arithmetic mean (UPGMA) dendrogram showed some unity among upstream
and downstream subpopulations within one stream and eleven populations. The Shannon index of genetic diversity was 0.109 for
one stream population and 0.313 for total genetic diversity, suggesting relatively high genetic diversity. Analysis of molecular
variance (AMOVA) revealed that 84.1% of the total genetic diversity occurred among populations and the remaining diversity
(15.9%) occurred within populations. Significant genetic differentiation occurred among populations in the Kinki district.
These results suggest that conservation of each population is important for maintaining genetic diversity of R. nipponicus in this district.
An erratum to this article can be found at 相似文献
6.
Allozyme variation was investigated in two local populations of Bulbophyllum drymoglossum and three populations Sarcanthus scolopendrifolius, two rare and endangered lithophytes and epiphytes from South Korea. Genetic diversity was extremely low within populations
(mean H
e = 0.011 for B. drymoglossum; 0.002 for S. scolopendrifolius). Among the putative screened 21 loci, we found only one polymorphic locus for each species. Only one polymorphic locus,
detected just one population of each species, revealed significantly high degree of population differentiation between and
among populations (F
ST = 0.253 for B. drymoglossum and F
ST = 0.899 for S. scolopendrifolius). These results suggest that genetic drift (consequence of a very small effective population size), coupled with a limited
gene flow would play a major role in shaping population genetics of these species in South Korea. The current status of both
species (small population sizes, spatially isolated populations, and highly localized habitats) in addition to the extremely
low levels of genetic diversity and reckless collection of endangered orchids by plant sellers, significantly threaten the
long-term survival of these species in Korea. Conservation of the two species requires both in situ strategies, by introducing of genets to increase effective population sizes by minimizing adverse effects (e.g., outbreeding
depression and genetic swamping by non-native genotypes), and ex situ strategies, such as collection of genets from clonal ramets. 相似文献
7.
Heparan sulfate proteoglycans play a vital role in signaling of various growth factors in both Drosophila and vertebrates. In Drosophila, mutations in the tout
velu (ttv) gene, a homolog of the mammalian EXT1 tumor suppressor gene, leads to abrogation of glycosaminoglycan (GAG) biosynthesis. This impairs distribution and signaling
activities of various morphogens such as Hedgehog (Hh), Wingless (Wg), and Decapentaplegic (Dpp). Mutations in members of
the exostosin (EXT) gene family lead to hereditary multiple exostosis in humans leading to bone outgrowths and tumors. In this study, we provide
genetic and biochemical evidence that the human EXT1 (hEXT1) gene is conserved through species and can functionally complement the ttv mutation in Drosophila. The hEXT1 gene was able to rescue a ttv null mutant to adulthood and restore GAG biosynthesis. 相似文献
8.
Vesna Milankov Gunilla Ståhls Jelena Stamenković Ante Vujić 《Conservation Genetics》2008,9(5):1125-1137
The genetic structure of 10 populations of the Merodon aureus group from the Balkan Peninsula was examined through allozyme electrophoresis and mitochondrial DNA sequencing of the cytochrome
c oxidase subunit I (COI). Six diagnosable cryptic taxa were identified within the morphologically defined species M. aureus Fabricius, 1805 and M. cinereus (Fabricius, 1794), with clear separation of the populations (((M. aureus A + M. aureus B) + cinereus complex) + M. aureus C). The parsimony analysis of COI sequence data of the aureus–cinereus complex using Merodon avidus A species as an outgroup resulted in two main clades, (M. aureus A + M. aureus B) and ((M. aureus C + M. cinereus B + M. cinereus C) + M. cinereus A), which differed on average by 5.7%. The observed spatial distribution of the taxonomic diversity of the group suggested
that these taxa originated from a common ancestral population in the Mediterranean. Identification of genetic uniqueness and
genetic endemism emphasizes the importance of molecular markers and estimation of genetic diversity in recognition of conservation
units. The primary goals of the conservation measures that we propose are the protection of phylogenetic lineages within the
highly diverse M. aureus group taxa and conservation of the genetic variation through management of important areas. 相似文献
9.
Na Chen Yan-Zhuo Yang Xiao-li Yang Xing-xu Zhang Chun-jie Li 《Conservation Genetics》2008,9(4):961-963
Microsatellites are often highly variable and abundant in most complex genomes, therefore are widely used in population genetic
studies. In this study, twelve polymorphic microsatellite loci were isolated and characterized for the Achnatherum inebrians, a plant abundant in grasslands of Northwest China. Characterization of 24 A. inebrians individuals form four geographically distant populations (Gansu, Qinghai, Xinjiang and Inner Mongolia provinces) showed moderate
to high allelic diversity ranging from 3 to 13 alleles per locus, and the expected heterozygosity ranging from 0.41 to 0.67.
No evidence of linkage disequilibrium was found for any locus pairwise comparisons. The markers described here will be useful
for investigating the genetic diversity, genetic structure and gene flow of this species.
Na Chen and Yan-Zhuo Yang contributed equally to this work. 相似文献
10.
We used random amplified polymorphic DNA markers (RAPDs) to assess genetic variation between- and within-populations of Anisodus tanguticus (Solanaceae), an endangered perennial endemic to the Qinghai-Tibetan Plateau with important medicinal value. We recorded
a total of 92 amplified bands, using 12 RAPD primers, 76 of which (P = 82.61%) were polymorphic, and calculated values of Ht and Hsp of 0.3015 and 0.4459, respectively, suggesting a remarkably high rate of genetic variation at the species level. The average
within-population diversity also appeared to be high, with P, He and Hpop values of 55.11%, 0.1948 and 0.2918, respectively. Analyses of molecular variance (AMOVA) showed that among- and between-population
genetic variation accounted for 67.02% and 32.98% of the total genetic variation, respectively. In addition, Nei’s coefficient
of differentiation (GST) was found to be high (0.35), confirming the relatively high level of genetic differentiation among the populations. These
differentiation coefficients are higher than mean corresponding coefficients for outbreeding species, but lower than reported
coefficients for some rare species from this region. The genetic structure of A. tanguticus has probably been shaped by its breeding attributes, biogeographic history and human impact due to collection for medicinal
purposes. The observed genetic variations suggest that as many populations as possible should be considered in any planned
in situ or ex situ conservation programs for this species. 相似文献
11.
A high-frequency and simple procedure for Agrobacterium tumefaciens-mediated genetic transformation of the medicinal plant Salvia miltiorrhiza was developed. Leaf discs were pre-cultured on MS medium supplemented with 6.6 μmol l−1 BAP and 0.5 μmol l−1 NAA for one day, then co-cultured with A. tumefaciens strain EHA105 harboring the plasmid pCAMBIA 2301 for three days on the same medium. Regenerated buds were obtained on selection
medium (co-culture medium supplemented with 60 mg l−1 kanamycin and 200 mg l−1 cefotaxime) after two cycles’ culture of 10 days each and then transferred to fresh MS medium with 60 mg l−1 kanamycin for rooting. Fifteen days later, the rooted plantlets were obtained and then successfully transplanted to soil.
The transgenic nature of the regenerated plants was confirmed by PCR, Southern hybridization analysis and GUS histochemical
assay. Averagely, 1.1 independent verified transgenics per explant plated were obtained through this protocol. Adopting this
procedure, positive transformed plants could be obtained within 2–3 months from mature seeds germination to transplant to
soil, and more than 1,000 transgenic plants with several engineered constructs encoding different genes of interest were produced
in our lab in the past two years. 相似文献
12.
Echinops setifer is an endangered grassland plant species in Japan. We isolated and characterized nine microsatellite loci in this species.
The number of alleles ranged from 3 to 7 and expected heterozygosities from 0.108 to 0.761. These markers described here will
be useful for investigating the genetic diversity, genetic structure and gene flow, and planning for conservation of E. setifer. 相似文献
13.
This report deals with micropropagation of the critically endangered and endemic Turkish shrub, Thermopsis turcica using callus, root and cotyledonary explants. Callus cultures were initiated from root and cotyledon explants on MS medium
supplemented with 0.5–20 μM NAA or 2,4-D. The root explants were found to be better in terms of quick responding and callusing
percentages as compared to the cotyledons. Organogenic callus production with adventitious roots and shoots were obtained
on MS medium with only NAA. The calli obtained with NAA, root and cotyledonary explants were cultured with BA and kinetin
(2–8 μM) alone or in combination with a low level (0.5 μM) of 2,4-D or NAA. The best regeneration of shoots from root explants
was observed on hormone-free MS medium. NAA with BA or kinetin in the medium improved shoot induction from the calli obtained
with NAA. Maximum percentage of shoots (93.3%), maximum number of shoots (6.2) and maximun length of shoots (8.22 cm) were
achieved from cotyledonary explants at 4 μM BA and 0.5 μM NAA. The presence of 0.5 μM or higher levels of 2,4-D in shoot induction
medium inhibited the regeneration in T. turcica explants. 83% of in vitro rooting was attained on pulsed-IBA treated shoots. The regenerated plants with well developed shoots and roots were successfully
acclimatized. Application of this study’s results has the potential to conserve T. turcica from extinction. 相似文献
14.
The microtubule-binding protein tau has been investigated for its contribution to various neurodegenerative disorders. However,
the findings from transgenic studies, using the same tau transgene, vary widely among different laboratories. Here, we have investigated the potential mechanisms underlying tauopathies
by comparing Drosophila (d-tau) and human (h-tau) tau in a Drosophila model. Overexpression of a single copy of either tau isoform in the retina results in a similar rough eye phenotype. However, co-expression of Par-1 with d-tau leads to lethality, whereas co-expression of Par-1 with h-tau has little effect on the rough eye phenotype. We have found analogous results by comparing larval proteomes. Through genetic
screening and proteomic analysis, we have identified some important potential modifiers and tau-associated proteins. These
results suggest that the two tau genes differ significantly. This comparison between species-specific isoforms may help to clarify whether the homologous
tau genes are conserved.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
This study was supported by the National Science Foundation of China (30270341; 30630028), the Multidisciplinary Program (Brain
and Mind) of the Chinese Academy of Sciences, the Major State Basic Research Program (“973 program”; G2000077800; G2006CB806600;
2006CB911003), the Precedent Project of Important Intersectional Disciplines in the Knowledge Innovation Engineering of the
Chinese Academy of Sciences (KJCX1-09-03). 相似文献
15.
Summary This study reports a protocol for successful micropropagation of Decalepis arayalpathra (Joseph and Chandras) Venter. (Janakia arayalpathra Joseph and Chandrasekhran; Periplocaceae), a critically endangered and endemic ethnomedicinal plant in the southern forests of the Western Ghats which is overexploited
for its tuberous medicinal roots by the local Kani tribes. Natural regeneration is rare and conventional propagation is difficult.
Conservation of the species through micropropagation was attempted. The nodal explants of greenhouse-raised plants, were more
desirable than cotyledonary nodal explants of aseptic seedlings. The basal nodes (73%) of 12–16-wk-old greenhouse-grown plants
cultured in Murashige and Skoog (MS) medium containing 12.96 μM 6-benzyladenine (BA), 2.48 μM 2-isopentenyladenine (2-ip) and 2.68 μM α-naphthaleneacetic acid (NAA) formed 16–17 cm long unbranched robust solitary shoots in 8 wk. Cotyledonary nodal explants
cultured in the same medium showed multiple shoot formation and axillary branching. But the shoots were thin, fragile and
not suitable for mass propagation. Single nodes of a solitary shoot subcultured on MS medium containing 2.22 μM BA and 0.24 μM 2-ip together produced 9.8±0.3 nodes from 18.0±0.6 cm long shoots within 5–6 wk. The basal nodes of the shoots so formed
were repeatedly subcultured to increase the stock of propagules while the 2.5–3.0 cm terminal cuttings were used for rooting.
The best root induction (68%) and survival (86%) was achieved on half-strength MS medium supplemented with 1.07 μM NAA. Field-established plants showed uniform growth and phenotypic similarity to parental stock. 相似文献
16.
Nine polymorphic microsatellite loci were developed and characterized for Handeliodendron bodinieri, an endangered tree endemic to karst forest in southwest China. Each locus displayed between 4 and 11 alleles. The observed
heterozygosity ranged from 0.345 to 0.931 and expected heterozygosity varied from 0.414 to 0.824. The combined probabilities
of paternity exclusion over all loci were 0.931 for P
r(Ex1) and 0.993 for P
r(Ex2), respectively. These loci represent a powerful tool in investigating gene flow and population structure in natural populations
of H. bodinieri. 相似文献
17.
Genetic diversity in the northernmost<Emphasis Type="Italic"> Oryza rufipogon</Emphasis> populations estimated by SSR markers 总被引:16,自引:0,他引:16
Song ZP Xu X Wang B Chen JK Lu BR 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,107(8):1492-1499
To estimate genetic diversity of the residual northern populations of Oryza rufipogon, a total of 232 individuals from six populations were analyzed using microsatellites (SSRs). The O. rufipogon populations with different status included three from Dongxiang (Jiangxi Province) and three from Chaling (Hunan Province) in China. The 23 rice SSR primer pairs selected from the RiceGenes Database detected a total of 115 alleles, indicating that all the SSR loci were polymorphic in this study. The total gene diversity was 0.919 in the six O. rufipogon populations, and the Donxiang populations showed higher diversity than the Chaling populations. More significant genetic differentiation and less gene flow were found among the Dongxiang populations than those from Chaling. The two putative introgressed populations showed relatively high genetic variation. One in situ conserved population from Dongxiang had the lowest level of genetic diversity. The re-introduced population from Chaling restored about 90% of the genetic variation, compared with the original source population. It is concluded from these results that a relatively high level of genetic variation resided in the northern O. rufipogon populations and continued efforts of conservation of these populations are needed; and that the conservation of some Chaling and Dongxiang populations has been effective in preventing gene flow from cultivated rice. Introgression of cultivated rice demonstrated significant impacts on genetic variability of the O. rufipogon populations, and should be carefully considered in conserving this wild rice. This study also suggested that re-introduction to its original habitats is an effective approach to restore O. rufipogon populations.Communicated by J.S. Heslop-Harrison 相似文献
18.
Yessica Rico Consuelo Lorenzo Francisco X. González-Cózatl Eduardo Espinoza 《Conservation Genetics》2008,9(6):1467-1477
The Tehuantepec jackrabbit (Lepus flavigularis) is an endangered species restricted to a small area in the Isthmus of Tehuantepec, Oaxaca, Mexico. To evaluate its phylogeographic
structure, population genetics, and demographic history we sequenced the mitochondrial Control Region hypervariable domain
(CR-1) for 42 individuals representing the entire species range. Phylogenetic patterns indicated that this species is subdivided
into two highly divergent clades, with an average nucleotide genetic distance of 3.7% (TrN) between them. Clades A and B are
geographically distributed in non-overlapping areas to the west and to the east of the Isthmus of Tehuantepec, respectively.
Genetic diversity indices showed reduced genetic variability in L. flavigularis when compared to other species of Lepus within main clades and within populations. This low genetic diversity coupled with the restricted distribution to very small
areas of occurrence and limited gene flow suggest that genetic drift has played an important role in the evolution of this
species. Historical demographic analysis also pointed out that these two clades underwent a recent population expansion that
started about 9,000 years ago for clade A and 3,200 years ago for clade B during the Holocene. Consequently, from the conservation
perspective our results suggest that populations included in clades A and B should be regarded as distinct evolutionary lineages. 相似文献
19.
Ikuyo Saeki 《Ecological Research》2008,23(4):719-727
Japanese red maple, Acer pycnanthum, is an endangered wetland species having dioecious sex expression. Prior studies conclude that land development has caused
severe loss of habitat, and seedling regeneration is rare. However, information is lacking on sexual reproduction, which is
the first critical stage of regeneration. My research objective was to describe flowering and fruiting characteristics of
Japanese red maple, focusing on tree sizes at the onset of flowering, factors affecting flowering regularity and fruit abundance,
periodicity of fruit production, and sex ratio. In a study of a young population, Japanese red maple initiated flowering at
a small size under 100% light intensity. Initiation of flowering occurred at relatively lower height in males than females,
and males flowered more regularly than females. A survey of 1,106 clones from 46 natural populations revealed that male clones
were significantly more abundant than female clones. In a 4-year study of mature populations, nearly all clones flowered regularly,
and fruit abundance of dominant females was typically high. Fruit abundance at the population level also remained high, although
fruit abundance of individual female clones varied year by year. Therefore, sexual reproductive ability is highly vigorous.
Sex ratio exhibited a major deviation from a 1:1 ratio in populations with a small number of clones. In conservation planning,
we should prioritize avoidance of an unbalanced sex ratio by increasing population sizes. In addition, populations having
many clones >40 cm dbh with large, well-lighted crowns have a high potential of regular and abundant seed production. 相似文献