共查询到20条相似文献,搜索用时 15 毫秒
1.
Evaluation of allelic diversity at chloroplast microsatellite loci among common wheat and its ancestral species 总被引:14,自引:0,他引:14
T. Ishii N. Mori Y. Ogihara 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(6-7):896-904
Twenty four chloroplast microsatellite loci having more than ten mononucleotide repeats were identified from the entire chloroplast
DNA sequence of common wheat, Triticum aestivum cv Chinese Spring. For each microsatellite, a pair of primers were designed to produce specific PCR products in the range
of 100– 200 bp. The allelic diversity at the microsatellite loci was evaluated using 43 accessions from 11 Triticum and Aegilops species involved in wheat polyploid evolution. Polymorphic banding patterns were obtained at 21 out of 24 chloroplast microsatellite
loci. The three monomorphic microsatellites were found to be located in coding regions. For the polymorphic microsatellites,
the number of alleles per microsatellite ranged from 2 to 7 with an average of 4.33, and the diversity values (H) ranged from
0.05 to 0.72 with an average of 0.47. Significant correlations (P<0.01) were observed between the number of repeats and the number of alleles, and between the number of repeats and diversity
value, respectively. The genetic diversity explained by chloroplast microsatellites and nuclear RFLP markers were compared
using 22 tetraploid accessions. Although the number of alleles for nuclear RFLP markers was found to be higher than that for
chloroplast microsatellites, similar diversity values were observed for both types of markers. Among common wheat and its
ancestral species, the percentages of common chloroplast microsatellite alleles were calculated to examine their phylogenetic
relationships. As a result, Timopheevi wheat species were clearly distinguished from other species, and Emmer and common wheat
species were divided into two main groups, each consisting of a series of wild and cultivated species from tetraploid to hexaploid.
This indicates that the two types of chloroplast genomes of common wheat might have independently originated from the corresponding
types of wild and cultivated Emmer wheat species.
Received: 6 October 2000 / Accepted: 13 March 2001 相似文献
2.
Elm breeding programs worldwide have relied heavily on Asian elm germplasm, particularly Ulmus pumila, for the breeding of Dutch elm disease tolerant cultivars. However, the extent and patterning of genetic variation in Asian elm species is unknown. Therefore, the objective of this research was to determine the extent of genetic diversity among 53 U. pumila accessions collected throughout the People's Republic of China. Using 23 microsatellite loci recently developed in the genus Ulmus, a total of 94 alleles were identified in 15 polymorphic and 4 monomorphic loci. The average number of alleles per locus was 4.9, with a range of 1-11 alleles. Gene diversity estimates per locus ranged from 0.08 to 0.87, and the non-exclusion probability for the 15 polymorphic loci combined was 0.7 x 10(-9). Nineteen region-specific alleles were identified, and regional gene diversity estimates were moderately high (0.48-0.57). The genetic relationships among accessions and regions were estimated by UPGMA and principal coordinate analysis. Both techniques discriminated all accessions and regions. Two microsatellite markers (UR175 + UR123 or Ulm-3) were sufficient to discriminate up to 99.7% of the accessions studied. This research provides useful information for DNA-based fingerprinting, breeding, ecological studies, and diversity assessment of elm germplasm. 相似文献
3.
KYUNG‐HO MA KWANG‐HO KIM ANUPAM DIXIT JAE‐WOONG YU JONG‐WOOK CHUNG JEONG‐HEUI LEE EUN‐GI CHO TAE SAN KIM YONG‐JIN PARK 《Molecular ecology resources》2006,6(3):689-691
A microsatellite‐enriched library of Job's tears (Coix lacryma‐jobi L. var. Ma‐yuen Stapf) was constructed using a modified biotin–streptavidin capture method. After screening, 17 polymorphic microsatellites were used for diversity analysis among 30 Job's tears accessions. The number of alleles ranged from one to five alleles per locus with an average of 2.8 alleles. Expected heterozygosity (HE) and polymorphism information content (PIC) ranged from 0 to 0.676 and from 0 to 0.666, respectively. The newly developed microsatellite markers are expected to be very valuable tools for evaluation of genetic diversity among large germplasm collection of Job's tears present in our Korean Gene Bank. 相似文献
4.
Microsatellite analysis of Aegilops tauschii germplasm 总被引:8,自引:0,他引:8
E. Pestsova V. Korzun N. P. Goncharov K. Hammer M.W. Ganal M.S. Röder 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(1-2):100-106
The highly polymorphic diploid grass Aegilops tauschii isthe D-genome donor to hexaploid wheat and represents a potential source for bread wheat improvement. In the present study
microsatellite markers were used for germplasm analysis and estimation of the genetic relationship between 113 accessions
of Ae. tauschii from the gene bank collection at IPK, Gatersleben. Eighteen microsatellite markers, developed from Triticum aestivum and Ae. tauschii sequences, were selected for the analysis. All microsatellite markers showed a high level of polymorphism. The number of
alleles per microsatellite marker varied from 11 to 25 and a total of 338 alleles were detected. The number of alleles per
locus in cultivated bread wheat germplasm had previously been found to be significantly lower. The highest levels of genetic
diversity for microsatellite markers were found in accessions from the Caucasian countries (Georgia, Armenia and the Daghestan
region of Russia) and the lowest in accessions from the Central Asian countries (Uzbekistan and Turkmenistan). Genetic dissimilarity
values between accessions were used to produce a dendrogram of the relationships among the accessions. The result showed that
all of the accessions could be distinguished and clustered into two large groups in accordance with their subspecies taxonomic
classification. The pattern of clustering of the Ae. tauschii accessions is according to their geographic distribution. The data suggest that a relatively small number of microsatellites
can be used to estimate genetic diversity in the germplasm of Ae. tauschii and confirm the good suitability of microsatellite markers for the analysis of germplasm collections.
Received: 8 September 1999 / Accepted: 7 October 1999 相似文献
5.
Genetic diversity in spring bread wheat (T.␣aestivum L.) was studied in a total of 69 accessions. For this purpose, 52 microsatellite (SSR) markers were used and a total of 406
alleles were detected, of which 182 (44.8%) occurred at a frequency of <5% (rare alleles). The number of alleles per locus
ranged from 2 to 14 with an average of 7.81. The largest number of alleles per locus occurred in the B genome (8.65) as␣compared
to the A (8.43) and D (5.93) genomes, respectively. The polymorphism index content (PIC) value varied from 0.24 to 0.89 with
an average of 0.68. The highest PIC for all accessions was found in the B␣genome (0.71) as compared to the A (0.68) and D␣genomes
(0.63). Genetic distance-based method (standard UPGMA clustering) and a model-based method (structure analysis) were used for cluster analysis. The two methods led to analogical results. Analysis of molecular variance (AMOVA)
showed that 80.6% of the total variation could be explained by the variance within the geographical groups. In comparison
to the diversity detected for all accessions (H
e
= 0.68), genetic diversity among European spring bread wheats was H
e
= 0.65. A comparatively higher diversity was observed between wheat varieties from Southern European countries (Austria/Switzerland,
Portugal/Spain) corresponding to those from other regions. 相似文献
6.
? Premise of the study: Chloroplast microsatellites were developed in Theobroma cacao to examine the genetic diversity of cacao cultivars in Trinidad and Tobago. ? Methods and Results: Nine polymorphic microsatellites were designed from the chloroplast genomes of two T. cacao accessions. These microsatellites were tested in 95 hybrid accessions from Trinidad and Tobago. An average of 2.9 alleles per locus was found. ? Conclusions: These chloroplast microsatellites, particularly the highly polymorphic pentameric repeat, were useful in assessing genetic variation in T. cacao. In addition, these markers should also prove to be useful for population genetic studies in other species of Malvaceae. 相似文献
7.
Bryan D. Neff Mart R. Gross 《Evolution; international journal of organic evolution》2001,55(9):1717-1733
Abstract We analyze published data from 592 AC microsatellite loci from 98 species in five vertebrate classes including fish, reptiles, amphibians, birds, and mammals. We use these data to address nine major questions about microsatellite evolution. First, we find that larger genomes do not have more microsatellite loci and therefore reject the hypothesis that microsatellites function primarily to package DNA into chromosomes. Second, we confirm that microsatellite loci are relatively rare in avian genomes, but reject the hypothesis that this is due to physical constraints imposed by flight. Third, we find that microsatellite variation differs among species within classes, possibly relating to population dynamics. Fourth, we reject the hypothesis that microsatellite structure (length, number of alleles, allele dispersion, range in allele sizes) differs between poikilotherms and homeotherms. The difference is found only in fish, which have longer microsatellites and more alleles than the other classes. Fifth, we find that the range in microsatellite allele size at a locus is largely due to the number of alleles and secondarily to allele dispersion. Sixth, length is a major factor influencing mutation rate. Seventh, there is a directional mutation toward an increase in microsatellite length. Eighth, at the species level, microsatellite and allozyme heterozygosity covary and therefore inferences based on large-scale studies of allozyme variation may also reflect microsatellite genetic diversity. Finally, published microsatellite loci (isolated using conventional hybridization methods) provide a biased estimate of the actual mean repeat length of microsatellites in the genome. 相似文献
8.
Eder Jorge de Oliveira Vanusia Batista Oliveira Amorim Edneide Luciana Santiago Matos Juliana Leles Costa Milene da Silva Castellen Juliano Gomes Pádua Jorge Luiz Loyola Dantas 《Plant Molecular Biology Reporter》2010,28(3):519-530
A set of 81 new microsatellite markers for Carica papaya L. previously identified by data mining using freely available sequence information from Genbank were tested for polymorphism
using 30 germplasm accessions from the Papaya Germplasm Bank (PGM) at Embrapa Mandioca e Fruticultura Tropical (CNPMF) and
18 landraces. The data were used to estimate pairwise genetic distances between the genotypes. A neighbor-joining based dendrogram
was used to define clusters and infer possible genetic structuring of the collection. Most microsatellites were polymorphic
(73%), with an observed number of alleles per locus ranging from one to eleven. The levels of observed and expected heterozygosity
for 51 polymorphic loci varied from 0.00 to 0.85 and from 0.08 to 0.82, averaging 0.19 and 0.59, respectively. Forty-four
percent of microsatellites showed polymorphism information content (PIC) higher than 0.50. The compound microsatellites seem
to be more informative than dinucleotide and trinucleotide repeats in average alleles per locus and PIC. Among dinucleotides,
AG/TC or GA/CT repeat motifs exhibited more informativeness than TA/AT, GT/CA and TG/AC repeat motifs. The neighbor-joining
analysis based on shared allele distance could differentiate all the papaya accessions and landraces as well as differences
in their genetic structure. This set of markers will be useful for examining parentage, inbreeding and population structure
in papaya. 相似文献
9.
Genetic Diversity and Core Collection Evaluations in Common Wheat Germplasm from the Northwestern Spring Wheat Region in China 总被引:6,自引:0,他引:6
C. Y. Hao X. Y. Zhang L. F. Wang Y. S. Dong X. W. Shang J. Z. Jia 《Molecular breeding : new strategies in plant improvement》2006,17(1):69-77
Fluorescence microsatellite markers were employed to reveal genetic diversity of 340 wheat accessions consisting of 229 landraces
and 111 modern varieties from the Northwest Spring Wheat Region in China. The 340 accessions were chosen as candidate core
collections for wheat germplasm in this region. A core collection representing the genetic diversity of these accessions was
identified based on a cluster dendrogram of 78 SSR loci. A total of 967 alleles were detected with a mean of 13.6 alleles
(5–32) per locus. Mean PIC was 0.64, ranged from 0.05 to 0.91. All loci were distributed relatively evenly in the A, B and
D wheat genomes. Mean genetic richness of A, B and D genomes for both landraces and modern varieties was B > A > D. However,
mean genetic diversity indices of landraces changed to B > D > A. As a whole, genetic diversity of the landraces was considerably
higher than that of the modern varieties. The big difference of genetic diversity indices in the three genomes suggested that
breeding has exerted greater selection pressure in the D than the A or B genomes in this region. Changes of allelic proportions
represented in the proposed core collection at different sampling scales suggested that the sampling percentage of the core
collection in the Northwest Spring Wheat Region should be greater than 4% of the base collection to ensure that more than
70% of the variation is represented by the core collection.
Electronic supplementary material Electronic supplementary material is available for this article at
and accessible for authorised users. 相似文献
10.
S. Achtar M. Y. Moualla A. Kalhout M. S. Röder N. MirAli 《Russian Journal of Genetics》2010,46(11):1320-1326
Genetic diversity among 49 wheat varieties (37 durum and 12 bread wheat) was assayed using 32 microsatellites representing
34 loci covering almost the whole wheat genome. The polymorphic information content (PIC) across the tested loci ranged from
0 to 0.88 with average values of 0.57 and 0.65 for durum and bread wheat respectively. B-genome had the highest mean number
of alleles (10.91) followed by A genome (8.3) whereas D genome had the lowest number (4.73). The correlation between PIC and
allele number was significant in all genome groups accounting for 0.87, 074 and 0.84 for A, B and D genomes respectively,
and over all genomes, the correlation was higher in tetraploid (0.8) than in hexaploid wheat varieties (0.5). The cluster
analysis discriminated all varieties and clearly divided the two ploidy levels into two separate clusters that reflect the
differences in genetic diversity within each cluster. This study demonstrates that microsatellites markers have unique advantages
compared to other molecular and biochemical fingerprinting techniques in revealing the genetic diversity in Syrian wheat varieties
that is crucial for wheat improvement. 相似文献
11.
N. Zhao W. Ai Z. Shao B. Zhu S. Brosse J. Chang 《Zeitschrift fur angewandte Ichthyologie》2005,21(1):7-13
Four microsatellites were used to examine the genetic variability of the spawning stocks of Chinese sturgeon, Acipenser sinensis, from the Yangtze River sampled over a 3‐year period (1999–2001). Within 60 individuals, a total of 28 alleles were detected over four polymorphic microsatellite loci. The number of alleles per locus ranged from 4 to 15, with an average allele number of 7. The number of genotypes per locus ranged from 6 to 41. The genetic diversity of four microsatellite loci varied from 0.34 to 0.67, with an average value of 0.54. For the four microsatellite loci, the deviation from the Hardy–Weinberg equilibrium was mainly due to null alleles. The mean number of alleles per locus and the mean heterozygosity were lower than the average values known for anadromous fishes. Fish were clustered according to their microsatellite characteristics using an unsupervised ‘Artificial Neural Networks’ method entitled ‘Self‐organizing Map’. The results revealed no significant genetic differentiation considering genetic distance among samples collected during different years. Lack of heterogeneity among different annual groups of spawning stocks was explained by the complex age structure (from 8 to 27 years for males and 12 to 35 years for females) of Chinese sturgeon, leading to formulate an hypothesis about the maintenance of genetic diversity and stability in long‐lived animals. 相似文献
12.
Aziz Ebrahimi Abdolkarim Zarei Shaneka Lawson Keith E. Woeste M. J. M. Smulders 《Tree Genetics & Genomes》2016,12(6):114
Persian walnut (Juglans regia L.) is the world’s most widely grown nut crop, but large-scale assessments and comparisons of the genetic diversity of the crop are notably lacking. To guide the conservation and utilization of Persian walnut genetic resources, genotypes (n = 189) from 25 different regions in 14 countries on three continents were sampled to investigate their genetic relationships and diversity using ten microsatellite (SSR) loci. The SSRs amplified from 3 to 25 alleles per locus, with a mean value of 11.5 alleles per locus. The mean values of observed and expected heterozygosity were 0.62 and 0.73, respectively. Based on Nei’s genetic identity, accessions from Bratislava (Slovakia) and Antalya (Turkey) showed the lowest similarity (0.36), while accessions from Algeria and Tunisia as well as accessions from Debrecen (Hungary) and Trnava (Slovakia) had the highest similarity (0.97). Two populations from Iran (Alborz and Ardabil) had the highest number of private alleles (7 and 5), but they were quite different as they also had the lowest genetic identity when compared to the remaining populations as well as to each other. Although overall differentiation among regions was relatively low (F st = 0.07), cluster analysis grouped accessions generally but not completely according to geography. STRUCTURE software confirmed these results and divided the accessions into two main groups, separating accessions collected from Europe and North Africa from those from Greece and the Near East. Results indicate the presence of a likely center of diversity for Persian walnut in Eastern and Southeastern Europe. They also provide information that can be used to devise conservation actions. Notably, the genetic diversity of threatened populations from two regions in Iran should be conserved. 相似文献
13.
部分耐盐小麦品种(系)SSR位点遗传多样性研究 总被引:8,自引:3,他引:5
选择有多态性的32对SSR引物对80个小麦耐盐品种(系)进行遗传差异研究,共检测出155个等位变异,平均每个位点上有4.75个等位变异;供试80份耐盐小麦品种(系)来源广泛,遗传基础丰富,表现出较高的遗传多样性,遗传相似系数范围在0.26~0.81;聚类分析结果显示,冬性小麦品种(系)聚为一大类;春性小麦品种(系)也聚为一大类;一些系谱相同或相近的品种(系)遗传相似系数较大;A、B、D基因组中SSR位点平均等位变异差异不大,以B基因组较高. 相似文献
14.
Isolation of EST-derived microsatellite markers for genotyping the A and B genomes of wheat 总被引:39,自引:0,他引:39
Eujayl I Sorrells ME Baum M Wolters P Powell W 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(2-3):399-407
Genetic variation present in 64 durum wheat accessions was investigated by using three sources of microsatellite (SSR) markers:
EST-derived SSRs (EST-SSRs) and two sources of SSRs isolated from total genomic DNA. Out of 245 SSR primer pairs screened,
22 EST-SSRs and 20 genomic-derived SSRs were polymorphic and used for genotyping. The EST-SSR primers produced high quality
markers, but had the lowest level of polymorphism (25%) compared to the other two sources of genomic SSR markers (53%). The
42 SSR markers detected 189 polymorphic alleles with an average number of 4.5 alleles per locus. The coefficient of similarity
ranged from 0.28 to 0.70 and the estimates of similarity varied when different sources of SSR markers were used to genotype
the accessions. This study showed that EST-derived SSR markers developed in bread wheat are polymorphic in durum wheat when
assaying loci of the A and B genomes. A minumum of ten EST-SSRs generated a very low probability of identity (0.36×10−12) indicating that these SSRs have a very high discriminatory power. EST-SSR markers directly sample variation in transcribed
regions of the genome, which may enhance their value in marker-assisted selection, comparative genetic analysis and for exploiting
wheat genetic resources by providing a more-direct estimate of functional diversity.
Received: 19 December 2000 / Accepted: 17 April 2001 相似文献
15.
Simple sequence length polymorphism analysis was carried out to reveal microsatellite variation and to clarify the phylogenetic relationships among A-genome species of rice. Total DNA from 29 cultivars (23 Oryza sativa and 6 O. glaberrima) and 30 accessions of wild A-genome species (12 O. rufipogon, 5 O. glumaepatula, 2 O. longistaminata, 6 O. meridionalis, and 5 O. barthii) was used as a template for PCR to detect 24 nuclear and 10 chloroplast microsatellite loci. Microsatellite allelic diversity was examined based on amplified banding patterns. Microsatellites amplified clearly in all 59 accessions, with an average of 18.4 alleles per locus. The polymorphism information content (PIC) value ranged from 0.85 to 0.94, with an average of 0.89. At the species level, high average PIC values were observed in O. sativa (0.79) and O. rufipogon (0.80). For chloroplast microsatellites, the average number of alleles per locus and the average PIC value were 2.9 and 0.38, respectively. While the magnitude of diversity was much greater for nuclear microsatellites than for chloroplast microsatellites, they showed parallel patterns of differentiation for each taxonomic group. Using the ratio of common alleles (estimated as size of amplified fragments) as a similarity index, the average percentages of common microsatellite alleles were calculated between taxa. For both nuclear and chloroplast microsatellites, O. sativa showed the highest similarity values to O. rufipogon, and O. glaberrima was most similar to O. barthii. These data support previous evidence that these cultivars originated from the corresponding wild ancestral species. 相似文献
16.
Genetic relationships among common wheat varieties from the 10 wheat growing regions of China were assessed using SSR markers. The wheat varieties included 33 modern varieties and 63 landraces selected from the national gene bank collection of China. One hundred and four pairs of selected primers detected a total of 802 alleles, of which 234 were specific to A genome, 309 to B genome, and 221 to D genome. The average genetic richness per locus (A
ij
/loci) for A, B and D genomes were 6.88, 7.92 and 7.62, respectively. Their average genetic dispersion indices (H
t
) were 0.637, 0.694 and 0.656, respectively. The B genome showed the highest genetic diversity among the three wheat genomes. The landraces had a higher genetic diversity than the modern varieties, and the major difference between the landraces and the modern varieties in China existed in the D genome, followed by B and A genomes. The majority of the accessions (65.6%) had heterogeneity at the 112 loci detected. The highest heterogeneity locus percentages were 9.09 and 12.73 in the modern varieties and the landraces, respectively. SSR data were analyzed with NTSYS-pc software. The genetic similarities between accessions were estimated with the DICE coefficient. The accessions clustered into two groups, the modern varieties and the landraces by the un-weighted pair-group method using arithmetic average (UPGMA). The trend of correlation coefficients between genetic similarity matrices based on different numbers of random alleles and that of 802 alleles showed that 550 alleles were sufficient to construct a robust dendrogram. The separated simulations from six sub-samples revealed that 550 alleles were the minimum number required to confidently determine the genetic relationships. It was shown that the number of alleles (loci) needed do not have a strong association with the number of wheat lines in the sample size. These data suggested that 73 loci with good polymorphism are needed to reflect genetic relationships among accessions with more than 90% certainty. In the dendrogram, most accessions from the same wheat region were clustered together, and those from geographically adjacent regions usually appeared in the same small group. This indicated that genetic diversity of Chinese common wheat has a close association with their geographic distribution and ecological environment. 相似文献
17.
In this study, 28 simple sequence repeat (SSR) primer sets were used to analyze the genetic diversity, population structure, and genetic relationships among 37 accessions of foxtail millet from Korea, China and Pakistan. A total of 298 alleles were detected with an average allele number of 10.6 per locus among 37 foxtail millet accessions. The number of alleles per locus ranged from 2 (b226) to 20 (b236). Of the 298 alleles, 138 alleles (46.3%) were rare (frequency < 0.05), 152 alleles (51.0%) were detected at an intermediate frequency (range, 0.05?C0.50), and eight alleles (2.7%) were abundant (frequency > 0.50), respectively. The average gene diversity values were 0.652, 0.692, and 0.491 and polymorphic information content values were 0.621, 0.653, and 0.438, for accessions from Korea, China, and Pakistan, respectively. The accessions from China showed higher SSR diversity than those from Korea and Pakistan. A phylogenetic tree constructed using the un-weighted pair group methods with arithmetic mean algorithm revealed three major groups of accessions that were not congruent with geographical distribution patterns with a few exceptions. The lack of correlation between the accession clusters and their geographic location indicates that the diffusion of foxtail millet from China to Korea might have occurred through multiple routes. Our results provide support for the origin and diffusion route of foxtail millet in East Asia. This SSR-based assessment of genetic diversity, genetic relationships, and population structure among genetic resources of foxtail millet landraces will be valuable to foxtail millet breeding and genetic conservation programs in Korea. 相似文献
18.
JAE‐GYUN GWAG JONG‐WOOK CHUNG HUN‐KI CHUNG JEONG‐HEUI LEE KYUNG‐HO MA ANUPAM DIXIT YONG‐JIN PARK EUN‐GI CHO TAE‐SAN KIM SUK‐HA LEE 《Molecular ecology resources》2006,6(4):1132-1134
The present work reports the isolation and characterization of new polymorphic microsatellites in mung bean (Vigna radiata L.). Of 93 designed primer pairs, seven were found to amplify polymorphic microsatellite loci, which were then characterized using 34 mung bean accessions. The number of alleles ranged from two to five alleles per locus with an average of three alleles. Observed and expected heterozygosity values ranged from 0 to 0.088 and from 0.275 to 0.683, respectively. All seven loci showed significant deviations from Hardy–Weinberg equilibrium, whereas only one pairwise combination (GBssr‐MB77 and GBssr‐MB91) exhibited significant departure from linkage disequilibrium. These newly developed markers are currently being utilized for diversity assessment within the mung bean germplasm collection of the Korean Gene Bank. 相似文献
19.
Marco Manzelli Luca Pileri Nadia Lacerenza Stefano Benedettelli Vincenzo Vecchio 《Biodiversity and Conservation》2007,16(6):1715-1730
In the north-western region of Somalia, bordering Ethiopia, sorghum represents an important resources for human and animal
nutrition. The critical situation of Somalia is threatening the preservation of this valuable resource and it becomes urgent
to develop a strategy of correct evaluation of the sorghum germplasm in order to promote conservation and preservation programs.
Microsatellites, also known as Simple Sequence Repeats (SSRs), are reproducible molecular markers useful in assessing the
level of genetic diversity of plants. A total of 5 sorghum SSR-specific primer pairs were used to assess the genetic diversity
of Somali sorghum landraces. Extensive variation was found at the microsatellite loci analysed, except for a locus that resulted
in a monomorphic for some accessions. Considerable differences were found between total and effective number of alleles indicating
non uniform allele frequency. Moreover allele frequency at a single locus significantly changed among accessions. Total gene
diversity calculated for each locus ranged from 0.44 to 0.79. Most of the genetic diversity occurred within accessions demonstrating
that accessions are not under selection processes and/or there is a continuous exchange of genes between sorghum populations.
In any case, the patterns of clustering were significantly affected by the presence/absence of some alleles with high discriminant
weight. Accessions Carabi, Abaadiro, Masego Cas and Masego Cad represent distinct genotypes confirming finding observed in
previous phenotypic studies. The results highlight the central role of local farmers in maintaining and shaping local germplasm. 相似文献
20.
Use of microsatellites to evaluate genetic diversity and species relationships in the genus Lycopersicon 总被引:1,自引:0,他引:1
A. E. Alvarez C.C.M. van de Wiel M.J.M. Smulders B. Vosman 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(8):1283-1292
In order to determine how informative a set of microsatellites from tomato is across the genus Lycopersicon, 17 microsatellite loci, derived from regions in and around genes, were tested on 31 accessions comprising the nine species
of the genus. The microsatellite polymorphisms were used to estimate the distribution of diversity throughout the genus and
to evaluate the efficacy of microsatellites for establishing species relationships in comparison with existing phylogeny reconstructions.
Gene diversity and genetic distances were calculated. A high level of polymorphism was found, as well as a large number of
alleles unique for species. The level of polymorphism detected with the microsatellite loci within and among species was highly
correlated with the respective mating systems, cross-pollinating species having a significantly higher gene diversity compared
to self-pollinating species. In general, microsatellite-based trees were consistent with a published RFLP-based dendrogram
as well as with a published classification based on morphology and the mating system. A tree constructed with low-polymorphic
loci (gene diversity <0.245) was shown to represent a more-reliable topology than a tree constructed with more-highly polymorphic
loci.
Received: 19 February 2001 / Accepted: 26 March 2001 相似文献