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1.
Maize (Zea mays L.) landraces have the highest genetic variation and adaptation to the natural and anthropological environment where they have evolved. Surveying both qualitative and quantitative morphological traits of existing landraces may be useful in maintaining their genetic diversity and preserving them from genetic erosion. Our research deals with the morpho-phenological and agronomic characterization of a flint maize landrace, named 'Nostrano di Storo', still grown in an inland hilly environment in the low valley of Chiese River in Trentino, North-Eastern Italy. The majority of plants from twenty field populations proved to belong, with few exceptions (NSt2, NSt9, NSt11), to a single population. It means that the plant material long grown in this area and maintained by local farmers through yearly selection forms a single landrace within which some populations (i.e. NSt1, NSt3, NSt4, NSt7, NSt10, NSt18, NSt19, NSt20) could be considered as most representative and taken as 'core'. This is supported by the fact that the genetic variability was much higher within than between field populations: half of the plant and ear traits investigated did not show any significant difference between populations whereas all traits but two showed highly significant differences within populations. Selection carried out over the years by each farmer according to his own criteria produced little genetic differentiation within the original population. Gene flow among farmer populations, most likely occurred through both pollen dispersion to neighboring cultivated fields and seed exchange among farmers, may help to explain the low genetic differentiation. This information is useful for both planning conservation and recognizing the landrace as a unique germplasm source of specific geographic origin. 相似文献
2.
Mulatu Geleta Tomas Bryngelsson Endashaw Bekele Kifle Dagne 《Genetic Resources and Crop Evolution》2007,54(3):601-614
Genetic diversity of 70 populations of niger (Guizotia abyssinica) representing all its growing regions in Ethiopia was investigated using random amplified polymorphic DNA (RAPD) to reveal
the extent of its populations genetic diversity. Ninety-seven percent of the loci studied was revealed to be polymorphic for
the whole data set. The within population diversity estimated by Shannon diversity index and Nei gene diversity estimates
was revealed to be 0.395 and 0.158, respectively. The extent of genetic variation of populations from major niger producing
regions was significantly lower than that of populations from other regions; however, it is distributed regardless of altitude
of growth. Genetic differentiation between populations was estimated with Shannon index as G′
ST (0.432), Nei’s G
ST (0.242) and AMOVA based F
ST (0.350) and appears to be equivalent to the average values calculated from various RAPD based studies on outcrossing species.
Higher proportion of the variation detected by AMOVA resided within populations (64.58%) relative to the amount of variation
among populations (35.42%). UPGMA cluster analysis showed that most of the populations were clustered according to their region
of origin. However, some populations were genetically distant from the majority and seem to have unique genetic properties.
It is concluded that the crop has a wide genetic basis that may be used for the improvement of the species through conventional
breeding and/or marker assisted selection. Collection of germplasm from areas not yet covered and/or underrepresented is the
opportunity to broaden the genetic basis of genebank collection. 相似文献
3.
Bernardette Primieri Carelli Lee Tseng Sheng Gerald Felipe Gobbi Grazziotin Sergio Echeverrigaray 《Genetic Resources and Crop Evolution》2006,53(2):395-400
Random amplified polymorphic DNA markers (RAPD) were used to estimate the variability of 35 tomato accessions (Lycopersicon esculentum Mill.). A total of 257 reproducibly scorable bands were obtained from 20 primers, 78.6% of which were polymorphic. The percentage
distribution of RAPD markers shows a bimodal distribution, and the frequency of rare alleles is similar in commercial and
landrace accessions. Genetic distances among accessions were calculated and a dendrogram showing the genetic relationships
among them was constructed allowing for the separation of four groups. Twenty out of 23 Brazilian landraces fell within one
group, whereas commercial cultivars were distributed in the four groups. AMOVA analysis of RAPD data showed that, despite
the high within Brazilian landraces and commercial cultivars variation, these two groups are significantly different, indicating
that landraces can be a source of variation for breeding programs. 相似文献
4.
Random amplified polymorphic DNA markers were used to study sub-structure and genetic differentiation amongst 31 populations
(seven cultivated and 24 wild populations) belonging to 14 Asiatic Vigna species. Ten pre-selected RAPD primers generated 152 polymorphic amplification products. Estimates of polymorphism indices
were higher for the wild taxa in comparison to the cultivated forms. FST values between populations ranged from 0.111 to 0.801 and Nei’s genetic diversity values between and within species varied
from 0.26 to 0.70 and 0.04 to 0.56 respectively. The high FST and FCT values indicated strong subdivision of populations and high differentiation among species. Analysis of molecular variance
was performed by grouping the populations conforming to specific species. AMOVA was also performed separately to better resolve
the differentiation of species within mungo–radiata complex. Molecular phylogenetic relationships amongst the species of radiata–mungo complex; namely, black gram (V. mungo (L.) Hepper), green gram (V. radiata (L.) Wilczek), V. radiata var. sublobata, V. radiata var. setulosa, V. mungo var. silvestris and V. hainiana, were studied through cluster analyses. Two distinct groups were recognized within the complex, with population samples of
V. hainiana forming one cluster. Further, V. hainiana appeared to be equidistant to both V. radiata and V. mungo. 相似文献
5.
Miao-Miao Li Yu-Liang Cai Zeng-Qiang Qian Gui-Fang Zhao 《Genetic Resources and Crop Evolution》2009,56(4):455-464
In this study, the genetic diversity and differentiation of 10 natural Prunus pseudocerasus Lindl. populations were investigated using inter-simple sequence repeat (ISSR) markers. Totally, 18 selected primers generated
150 loci, with an average of 8.33 bands per primer. The results showed that the percentage of polymorphic bands (PPB) was pretty low at the population level (PPB = 1.13–32%), but relatively high at the species level (PPB = 84%). Besides, a high level of genetic differentiation among populations was detected based on the gene differentiation
coefficient (G
ST = 0.7118) and the hierarchical analysis of molecular variance (AMOVA) (Φ
ST = 64.53%, P < 0.001), in line with the low inter-population gene flow (N
m = 0.2025). Moreover, Mantel test revealed a significant correlation between genetic and geographic distances among the populations
(r = 0.5272, P < 0.005). The high level of intraspecific genetic diversity was probably related with its life history traits, while its
small population size and the resultant high levels of genetic drift and inbreeding might explain the low genetic diversity
within populations. The relatively high inter-population genetic differentiation was largely attributed to its small population
size, habitat fragmentation, the mode of pollen and seed dispersal, and geographic isolation. Based on the present study,
conservation strategies were proposed to preserve this valuable natural germplasm resource. 相似文献
6.
Jinggui Fang Chih-Cheng T. Chao Philip A. Roberts Jeffrey D. Ehlers 《Genetic Resources and Crop Evolution》2007,54(6):1197-1209
Cowpea is an important grain legume and hay crop of many tropical and subtropical regions, especially in the dry savanna region
of West Africa. The cowpea gene pool may be narrow because of a genetic bottleneck during domestication. Genetic variation
within specific breeding programs may be further restricted due to breeding methods, ‘founder effects’ and limited exchange
of germplasm between breeding programs. Genetic relationships among 60 advanced breeding lines from six breeding programs
in West Africa and USA, and 27 landrace accessions from Africa, Asia, and South America were examined using amplified fragment
length polymorphism (AFLP) markers with six near infrared fluorescence labeled EcoRI + 3/1bases/MseI + 3/1bases primer sets. A total of 382 bands were scored among the accessions with 207 polymorphic bands (54.2%). Despite
a diverse origin, the 87 cowpea accessions shared a minimum 86% genetic similarity. Principal coordinates analysis showed
clustering of breeding lines by program origin, indicating lack of genetic diversity compared to potential diversity. Accessions
from Asia and the Americas overlapped and were distinct from West African breeding lines, indicating that germplasm from Asia
and the Americas have common origins outside West Africa. US and Asian breeding programs could increase genetic variability
in their programs substantially by incorporating germplasm from West Africa, while national programs in West Africa should
consider introgression of Asian germplasm and germplasm from other parts of Africa into their programs to ensure long-term
gains from selection. 相似文献
7.
Shao-Qing Tang Xiao-Yun Bin Yun-Tao Peng Jun-Ya Zhou Li Wang Yang Zhong 《Genetic Resources and Crop Evolution》2007,54(5):1053-1061
Genetic variation of wild populations and cultivars of Luohanguo (Siraitia grosvenorii), a plant species endemic to southern China, was assessed using random amplified polymorphic DNA (RAPD) and amplified fragment
length polymorphism (AFLP) markers. Based on the results for 130 individuals from seven populations, a high level of genetic
diversity of Luohanguo was observed at the species level. The percentage of polymorphic loci (P) was 89.4%, Nei’s gene diversity (H
e) was 0.239, and Shannon’s information index (H
o) was 0.373 based on the combined AFLP and RAPD data. There was a high degree of genetic differentiation, with 45.1% of the
genetic variation attributed to differences between the populations. The genetic diversity of the Luohanguo cultivars is much
lower than that of wild populations (P = 41.8%, H
e = 0.141, H
o = 0.211), and a distinct genetic differentiation is observed between the cultivars and wild accessions. The pool of genetic
variation in the wild populations provides an excellent gene resource for Luohanguo breeding. 相似文献
8.
9.
Nivaldo Peroni Paulo Yoshio Kageyama Alpina Begossi 《Genetic Resources and Crop Evolution》2007,54(6):1333-1349
This study focuses the inter-relationships among the men, the use, and the intra-specific cassava diversity, under the perspective
of this crop evolutionary dynamics. The origin, the use and the current local management of varieties with high and low cyanogenic
potential are important questions around cassava domestication. We collected 169 local varieties identified as “sweet” or
“bitter” cassava by traditional farmers from Atlantic Forest and Amazon (Medium Negro River Basin), Brazil. Using a population
genetics and an ethnobotany approach, the diversity and the genetic structure of cassava were evaluated. We found a total
of 115 vernacular names, and in the Atlantic Forest sample the average genetic diversity (H
S = 0.654) was higher for the sweet varieties than for bitter ones (0.582). The genetic differentiation coefficient (R
ST), used to estimate the diversity among groups, was 0.057 (P < 0.001), indicating that the divergence between the two groups is low. We obtained a low correlation between the morphological
and genetic distances, and the congruence was high when the ethnoclassification and the genetic structure were considered.
We discuss the adaptive advantages of the sweet varieties use, the current socio-economic changes in bitter varieties use,
and the ecological history of these variety groups. 相似文献
10.
Accurate assessment of genetic similarity is important for plant breeding, germplasm enhancement and conservation of plant
genetic resources. A comparative analysis of genome diversity among a group of six-rowed spring barley (Hordeum vulgare L.) cultivars was carried out using sequence-specific amplified polymorphism (S-SAP) and single nucleotide polymorphism (SNP),
with the results compared to the kinship coefficients derived from the pedigree data. Mean pair-wise GS values were estimated
to be 0.0957 ± 0.144 (Kinship), 0.491 ± 0.189 (SNPs), and 0.602 ± 0.098 (S-SAPs). S-SAP and SNP-based genetic similarity (GS)
values were normally distributed but kinship values had a non-normal and skewed distribution. Pair-wise correlation of GS
values were lowest for the S-SAP and the SNP matrices (r =; 0.040, p<0.230) and highest for the SNP and pedigree matrices (r =; 0.240, p < 0.001). Analysis of molecular variance (AMOVA) attributed about 90.4% of observed variation to the cultivars within each
of the malting and feed groups. Variance component between malting and feed groups was 6.6% for both SNP and S-SAP data suggesting
lack of a significant genetic differentiation along this agronomic division. The remaining 3% of variation was attributed
to genetic diversity within cultivars. Although both DNA-based marker systems were able to differentiate all barley cultivars,
significant difference were observed in the pattern of genetic relationships obtained by the two marker systems and the pedigree
data. 相似文献
11.
Toan Duc Pham Tri Minh Bui Gun Werlemark Tuyen Cach Bui Arnulf Merker Anders S. Carlsson 《Genetic Resources and Crop Evolution》2009,56(5):679-690
Sesame (Sesamum indicum L.) is a traditional oil crop cultivated throughout South East Asia. To estimate the genetic diversity of this crop in parts
at the region, 22 sesame accessions collected in Vietnam and Cambodia were analyzed using 10 RAPD markers. The 10 primers
generated 107 amplification products of which 88 were polymorphic fragments (83%). Genetic diversity of all populations was
Ht = 0.34 when estimated by Nei’s genetic diversity and species diversity was H′sp = 0.513 when estimated by Shannon diversity index. Genetic distance ranged from 0.03 to 0.43, with a mean genetic distance
of 0.23. The unweighted pair group method with arithmetic averages (UPGMA) cluster analysis for the 22 accessions divided
the material in four groups. The dendrogram revealed a clear division among the sesame accessions based on their geographical
region. Interestingly, some geographically distant accessions clustered in the same group, which might indicate the human
factor involved in the spreading of sesame varieties. The high level of polymorphism shown suggests that RAPD techniques can
also be useful for the selection of parents in sesame (Sesamum indicum L.) breeding program and for cultivar differentiation. 相似文献
12.
Analysis of Genetic Relationships among Turkish Cultivars and Breeding Lines of Lens culinatis Mestile Using RAPD Markers 总被引:1,自引:0,他引:1
Ertuğrul Yüzbaşıoğlu Sebahattin Özcan Leyla Açık 《Genetic Resources and Crop Evolution》2006,53(3):507-514
Randomly Amplified Polymorphic DNA markers were used to determine the genetic relationships among Turkish lentil cultivars
and breeding lines. Fourteen cultivars and thirteen breeding lines were evaluated to determine genetic variability using nine
random 10-mer primers (among 45 primers). Forty-one reproducible bands were obtained, 54% of which were polymorphic. Genetic
distances among cultivars and breeding lines were obtained from the simple matching coefficients (SM). The lowest genetic
distance was observed between the cultivars of Ali Dayi and Kafkas with 5.0%, while ‘Seyran-96’ and ‘Ozbek’ had the highest
genetic distance with 58.3%. An unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis was performed
on the distance matrix using Phylip software. The dendrogram clearly showed two distinct groups. The first group is composed
of Akm 565 and Akm 563. The second group contains all the cultivars and remaining eleven breeding lines. 相似文献
13.
Mario Augusto Pagnotta Linda Mondini Pasquale Codianni Clara Fares 《Genetic Resources and Crop Evolution》2009,56(3):299-310
Emmer wheat (Triticum dicoccon Schrank, 2n = 4x = 28) consists in a hulled wheat; its cultivation has been drastically reduced during the last century as a consequence of
its low yield. Recently, its agronomic and nutritive values, as well as the increase of popularity of organic agriculture,
have led to a renewed interest making its cultivation economically viable in the marginal lands with an increase of the cultivated
areas. In Italy, it mainly survives in few marginal lands of central and southern Italy, where local varieties, adapted to
the natural environment from where they originate, are used; moreover, some selected lines have also been developed. In the
present work, agro-morphological and qualitative traits, together with molecular analyses of 20 emmer accessions consisting
of Italian landraces, breeding lines, and cultivars, were performed. The field experiments were conducted for two consecutive
years (2001/2002–2002/2003) in two locations: Viterbo in central Italy, and Foggia in south Italy. The analyzed emmer wheat
accessions showed a good amount of genetic variability for both evaluated agro-morphological and molecular traits. This study
illustrates an increase in earliness, GY, TW, TKW, and YI going from landraces, breeding lines to cultivars, while the variability
does not change proportionally. 相似文献
14.
Makiko Mimura Clarice J. Coyne Marie W. Bambuck Thomas A. Lumpkin 《Genetic Resources and Crop Evolution》2007,54(3):497-508
Edamame [Glycine max (L.) Merr.] is a type of soybean selected for fresh or frozen vegetable use at an immature stage. Since edamame has a similar
protein content, milder flavor, nuttier texture, and is easier to cook when compared to grain soybean, it is being promoted
as a new vegetable for global consumption. Global production will require breeding programs for local adaptation; however,
limited research has been published on genetic diversity of edamame varieties for the assessment of genetic resources. Simple
sequence repeats (SSRs) were used to study the genetic diversity among 130 accessions, including edamame cultivars and landraces
from Japan, China and the US, and also the new breeding lines in the US. Although it is assumed that elite edamame cultivars
would have narrow genetic diversity, seventeen SSRs detected polymorphism to distinguish 99 of the 130 accessions. The cluster
analysis generated nine clusters and 18 outliers. Genetic diversity within Japanese edamame was lower than that within Chinese
vegetable soybean accessions (maodou), even though only 10 Chinese maodou were analyzed compared to 107 Japanese edamame.
Cluster analysis revealed that the patterns of SSR diversity in edamame can generally distinguish maturity classes and testa
color. We concluded that Japanese edamame have a narrow genetic base different from others and that SSRs can describe the
patterns of genetic diversity among the elite vegetable soybean. 相似文献
15.
Pan Dong Yu-Ming Wei Guo-Yue Chen Wei Li Eviatar Nevo You-Liang Zheng 《Genetic Resources and Crop Evolution》2009,56(1):121-136
Using the 8 specific primer pairs based on the conserved motifs of plant resistance genes, the plant disease resistance gene
analog polymorphisms (RGAPs) in 15 wild emmer wheat (Triticum dicoccoides) populations from Israel had been detected. High genetic variations at the RGAP loci were observed in T. dicoccoides populations. A total of 254 discernible bands were obtained among 115 accessions, and 192 bands (75.6%) were polymorphic.
Each genotype had a unique banding profile, and the genetic similarity coefficient ranged from 0.094 to 0.862. In T. dicoccoides, the proportion of polymorphic loci (P), the genetic diversity (He) and Shannon’s information index were 0.756, 0.362 and 0.541, respectively. The proportion of polymorphic loci (P) per population averaged 0.732 (range: 0.515–0.932); genetic diversity (He) averaged 0.271 (range: 0.212–0.338); and Shannon’s information index averaged 0.404 (range: 0.310–0.493). The coefficients
of genetic distance (D) among populations averaged 0.107 (range: 0.043–0.178), and the results of Mantel test (r = 0.168, P = 0.091) showed that the estimates of genetic distance were geographically independent. Neighbor-joining cluster analysis
suggested that the genetic relationships of T. dicoccoides populations were associated with their ecogeographic distribution. The hierarchical analysis of molecular variance (AMOVA)
and the coefficient of gene differentiation (G
ST
) values revealed that most of the variations were presented within populations, although significant differences among populations
and regions were also detected. The values of P and Shannon’s information index were negatively correlated with the two factors: Tdd (day–night temperature difference) and
Ev (mean annual evaporation), whereas they were positively correlated with one water factor: Rn (mean annual rainfall). The
correlation matrix between He in the RGAPs and geographic variables contained 20 significant (P < 0.05) correlations. The present study established that T. dicoccoides in Israel had a considerable amount of genetic variations at RGAP loci at least partly correlated with ecological factors. 相似文献
16.
A comparative characterization of 10 field populations of the maize (Zea mays var. indurata) landrace Nostrano di Storo was carried out using different types of PCR-based markers. The inbred line B73 and three synthetics (VA143, VA154 and VA157) selected from as many landraces were also used. Genetic diversity and relatedness were evaluated over 84 SSR and 53 I-SSR marker alleles using a total of 253 individual DNAs. Up to 23 alleles per SSR locus were scored while the average effective number of alleles per population was 6.99. Nei's total genetic diversity as assessed with SSR markers was HT = 0.851 while the average diversity within populations was HS = 0.795. The overall Wright's fixation index FST was as low as 0.066. Thus, more than 93% of the total variation was within population. Unique alleles over all SSR loci were found for six populations. An average of 17.7 marker alleles per I-SSR primer were scored with an effective number of marker alleles per locus of 1.34. The Shannon's diversity information index over all populations and I-SSR loci was 0.332, varying from 0.286 to 0.391. The extent of differentiation between populations was as low as GST = 0.091. Dice's genetic similarity matrices were estimated for both SSR and I-SSR markers. The mean genetic similarity coefficients within and between populations were respectively 0.269 and 0.217, for SSR markers, and 0.591 and 0.564, for I-SSR markers. UPGMA dendrograms displayed all field populations but one clustered into a distinct group, in which the synthetic VA154, selected from the Marano Vicentino landrace, was also included. One field population and the other two synthetics were clustered separately as well B73. The matrix correlation assayed by the Mantel's correspondence test was as high as 0.908. Findings suggest that, although a high variability can be found among plants, most plant genotypes belong to the same landrace called Nostrano di Storo. Although gene flow from commercial hybrids might have occurred, the large number of polymorphisms and the presence of both unique alleles and alleles unshared with B73 and synthetics are the main factors underlying the value of this flint maize landrace as a source of genetic variation and peculiar germplasm traits. Because of its exclusive utilization for human consumption, such a molecular marker characterization will be a key step for obtaining the IGP mark and so promote the in situ conservation and protection of the landrace Nostrano di Storo. 相似文献
17.
Yvonne Lokko Alfred Dixon Sam Offei Eric Danquah Martin Fregene 《Genetic Resources and Crop Evolution》2006,53(7):1441-1453
A study was conducted to determine the extent of genetic diversity among African cassava (Manihot esculenta Crantz) accessions resistant to the cassava mosaic virus disease (CMD), using simple sequence repeat (SSR) markers. The accessions
included a breeding stock (clone 58308), five improved lines, 62 CMD resistant and 10 CMD susceptible landraces. Genetic diversity
was assessed among accessions in five cluster groups derived from UPGMA analysis on data from 18 SSR primer pairs. Average
gene diversity, He, was high in all cluster groups, with an average heterozygosity of 0.591 ± 0.061. The estimator of inbreeding
Fis revealed a low level of inbreeding within groups and averaged −0.262 ± 0.142. Gene diversity among all accessions was
51.4% and gene diversity within cluster groups was 46.6%, while 4.8% was due to diversity between the different cluster groups.
The amount of genetic differentiation measured by Gst and Fst were 9.6% and 12.1% respectively, indicating a weak genetic
structure. 相似文献
18.
A wild tetraploid oat Avena maroccana Gdgr. was collected from the 11 populations in the periphery of Rommani and Casablanca geographic groups of Morocco. Genetic
diversity of the species was investigated using six allozyme systems. Allelic frequencies were scored representing eight polymorphic
and five monomorphic loci. Coefficient of gene differentiation (Gst) was 0.3019, which indicated great genetic differentiation. The number of alleles per locus was 2.6154, the percentage of
polymorphic loci was 61.54, and the expected heterozygosity was 0.2462 in all populations. Genetic diversity in A. maroccana was high in comparison to self-pollinated species. In total, nine heterozygotes resulting from outcrossing were found in
the progeny from M1, M3, M4, M22 and M26. The population of M7 had peculiar alleles Pgd–2SS and Pgd-1SS in high frequency. M9 had the lowest level of diversity out of the 11 populations. Geographic and genetic distances between
all the populations were not significantly correlated with each other (r = 0.0996). Cluster analysis showed that two groups, (M1, M22, M2 and M4) and (M3, M23, M8, M5 and M26) were apparently differentiated.
Two populations of the Casablanca group, M7 and M9 were independent from each other, and were separated distinctly from the
other populations. Genetic diversity of the Rommani and Casablanca groups was almost the same in all the parameters. This
was due to the similar man-made habitat such as roadside or rich fertile soil and brown clay soils. The population size of
A. maroccana was small and restricted to the narrow central Morocco with great genetic differentiation so that genetic diversity may be
reflected from the results of genetic drift and outcrossing heterozygote segregation. 相似文献
19.
Asako Kobayashi Kaworu Ebana Shuichi Fukuoka Tsukasa Nagamine 《Genetic Resources and Crop Evolution》2006,53(3):499-506
Landraces of rice (Oryza sativa L.) are valuable sources of genetic variation that have been lost in advanced cultivars. Seeds of a rice landrace stored
for almost 100 years were found on Sado Island in Niigata prefecture, Japan. This report aims to present basic data on the
genetic variation of this landrace, which was known as ‘Echizen’. Five samples of ‘Echizen’, consisting of two old samples,
one sample maintained on farm, and two lines regenerated from old seeds were compared with other advanced cultivars and landraces
using 19 microsatellite markers. Among the five samples of Echizen, the two stored samples showed greater diversity than the
other samples. Cluster analysis based on the UPGMA method also showed that old Echizen was a diverse landrace that could cover
the genetic diversity of most Japanese rice cultivars. 相似文献
20.
Andr W.G. van der Wurff Rieta Gols Ger Ernsting Nico M. van Straalen 《Pedobiologia》2005,49(2):167-174
We studied genetic variation and population differentiation in the springtail Orchesella cincta L. An earlier approach, using allozymes, revealed extremely low variation among and within populations from NW Europe. Microsatellite marker analysis showed higher genetic variation than allozymes, and agreed with the previously reported low population differentiation in the species. Analysis of molecular variance showed that genetic variation within populations amounted to 96.5% of the total variation, whereas the remaining 3.5% is accounted for by population differentiation. Population differentiation, as described by microsatellite markers and with the exception of one population, can be explained by an isolation by distance. Although the microsatellites are short, viz. only up to 12 repeat units, they appear to be useful tools in revealing population genetic structures in O. cincta. 相似文献