Polymorphic Random Amplified Polymorphic DNA Research Articles

Relationships among some cornelian cherry genotypes (Cornus mas L.) based on RAPD analysis

Turkey is an important producer of cornelian cherries (Cornus mas L.), especially in northern Anatolia. Seed propagation and long-term human selection has given rise to a great diversity of trees. Twenty-six cornelian cherry genotypes (CC1–CC26) from the Coruh Valley in northern Anatolia were evaluated for genetic relationships by using Randomly Amplified Polymorphic DNA (RAPD) markers, based on 56 decamer random primers, seven of which showed reliable polymorphisms. These seven primers generated 80 markers, with 77 (96.25%) displaying polymorphisms. Cluster analysis of the cornelian cherry genotypes was performed based on data from polymorphic RAPD bands, by using Jaccard’s similarity coefficient and the Unweighted pair-group method with arithmetic average (UPGMA) clustering method. A similarity matrix showed that the highest genetic similarity (0.913) was between CC15 and CC16 and the least (0.129) was between CC4 and CC16. The cophenetic correlation coefficient between the similarity matrix and the cophenetic matrix of the dendrogram was relatively high (r = 0.87), supporting the validity of the dendrogram. Based on these results, RAPD analysis can be used for the characterization and grouping of cornelian cherry genotypes. Genetically divergent genotypes identified in this study may be useful for future breeding programs. This is the first study demonstrating that RAPD analyses can be used to differentiate and classify cornelian cherry genotypes.

EVALUATION OF THE CYTOGENETIC EFFECT OF CYCLOOXYGENASE INHIBITOR; FLUNIXIN MEGLUMINE (FINADYNE)® IN RATS

A study was carried out to evaluate the effect of Flunixin meglumine (Finadyne)®; a cyclo-oxygenase inhibitor; on different cytogenetic parameters including mitotic index, chromosomal aberrations, quantitative estimation of nucleic acids (DNA and RNA) and detection of genetic diversity using Random Amplified Polymorphic DNA RAPD technique in rats. The experiment was conducted on 30 female albino rats divided into three equal groups each of ten as follows: The first group was the control group. The second group was intramuscularly injected with finadyne; 2.5 mg /kg body weight once daily for 7 successive days. The third group was intramuscularly injected with the same dose of finadyne for 30 days prolonged administration. Analysis of the obtained results indicated that, finadyne elicited a significant decrease in the mitotic index when intramuscularly injected to rats for 7 days and 30 days compared with the control .Only prolonged administration of finadyne for 30 days evoked a significantincrease in the mean values of the total structural chromosomal aberrations. Quantitative estimation of nucleic acids (DNA and RNA) revealed significant decrease in DNA and RNA contents of rats given finadyne for 30 days .Analysis of genetic identity and diversity using Random Amplified Polymorphic DNA (RAPD) technique by the means of random oligodeoxyribonucleotide primers showed that the numbers of produced bands were found to be variable among groups using different primers. DNA extracted from blood of rats injected with finadyne for 30 days showed the lowest numbers of polymorphic with unique bands compared with the control. The dendrogram based on the correlation matrix between different groups showed high similarity between amplified polymorphic bands of DNA of the control and those of rats treated with finadyne for 7 days while there was significant genetic diversity between DNA of rats treated with finadyne for 30 days compared with those of the control. Taken together, our findings are not in favor of the unjustified prolonged administration of flunixin meglumin due to the detectable hazard of cytogenetic influences.

Abundant genetic diversity in cultivated Codonopsis pilosula populations revealed by RAPD polymorphisms

Genetic diversity of seven cultivated populations of Codonopsis pilosula Nannf. from Longxi County, Gansu Province of China was estimated using randomly amplified polymorphic DNA (RAPD) markers. The 17 selected RAPD primers amplified 205 polymorphic bands out of a total of 235 (87.2%). Nei’s gene-diversity statistics and population differentiation parameters based on AMOVA analysis indicated that the cultivated C. pilosula populations remained a high level of genetic diversity with Hs = 0.299 and I = 0.450. A greater proportion of genetic diversity was found within (77%) rather than among (23%) the populations. In addition, we also detected that populations from different altitudes had a considerable genetic differentiation after 40 years of cultivation at the same site. Populations from higher altitude had lower genetic diversity than those from lower altitude. Our results suggested that irregular and sparse cultivation practices, i.e., random collecting, preserving, and planting seeds of the medicinal species without deliberate selection, might be an efficient way to conserve genetic resources of medicinal plants, in addition to their effective uses.

The impact of over-exploitation on the genetic structure of Turkish red pine (Pinus brutia Ten.) populations determined by RAPD markers

To determine the possible impact of over-exploitation on the genetic structure of Turkish red pine (Pinus brutia Ten.) populations, three natural and three over-exploited (human degraded) populations of the species in the Mediterranean region of Turkey were investigated with Randomly Amplified Polymorphic DNA (RAPD). With the 80 RAPD primers tested, 12 of them yielded 137 polymorphic RAPD fragments. Four of the studied populations maintained unique fragments. The mean proportion of polymorphic fragments for all populations ranged from 89.8 to 98.9% and there were no significant differences between natural (94.8%) vs. over-exploited populations (92.7%). The estimated heterozygosity values suggested that Turkish red pine maintains high levels of genetic diversity (range 0.24–0.28) though studied populations and grouped ones as natural (H = 0.28) vs. over-exploited (0.27) did not differ significantly. The mean F value indicated that the large portion of the total genetic diversity was within populations (93%), but this value was lower in the natural populations (92%) than in the over-exploited ones (94%). In over-exploited populations, excess of homozygosity was observed (about 6% higher) as compared to natural populations, indicating impacts of inbreeding in P. brutia.eST

Cultivars identification and their genetic relationships in Dimocarpus longan subspecies based on RAPD markers

Abstract Random amplified polymorphic DNA (RAPD) analysis was employed to identify cultivars and the relationships between 22 morphologically more or less alike genotypes of longan ssp. Fifteen registered cultivars and seven exotic primitive cultivated forms of longan ssp. were used in this study. The 26 primers, selected from 87 initially screened, generated 190 bands of which 102 were reproducible polymorphic and size-separated from 480 to 2300 bp. These polymorphic RAPD markers distinguished 22 genotypes by at least six marker differences. The use of only 28 RAPD markers amplified by primers A39, C59, C62, F10, and F44 were sufficient to identify uniquely all the genotypes, indicating that RAPD markers are efficient for use in genetic fingerprinting in longan ssp. Jaccard's similarity between pairs of genotypes ranged between 0.554 and 0.930 with a mean of 0.672. The unweighted pair-group method using arithmetic averages (UPGMA) dendrogram indicated that 19 genotypes were classified into two major groups. Each group was divided into two subgroups. Most of the genotypes developed/registered from the same country or same breeding center clustered very closely. One Taiwan cultivar ‘Fungkok’, one Chinese cultivar ‘Fuku Yan’, and one exotic primitive cultivated form ‘Malay’ from Malaysia were independently distant from the 19 genotypes of the two main groups. This information would be helpful for future genome mapping programs as well as for the application of intellectual breeder.

GENETIC STRUCTURE OF NATURAL POPULATIONS IN THE RED ALGAEGELIDIUM CANARIENSE(GELIDIALES, RHODOPHYTA) INVESTIGATED BY RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD) MARKERS1

Random amplified polymorphic DNA (RAPD) marker variation was analyzed in female gametophytes in natural populations ofGelidium canariense(Grunow) Seoane‐Camba ex Haroun, Gil‐Rodríguez, Diaz de Castro et Prud'Homme van Reine from the Canary Islands to estimate the degree and distribution of genetic variability and differentiation. A total of 190 haploid individuals were analyzed with 60 polymorphic RAPDs bands which produced 190 distinct multilocus genotypes. A high level of polymorphism was detected in all populations analyzed. Within‐population gene diversity ranged from 0.156 to 0.264. The populations on the island of Gran Canaria showed higher genetic variation than the other populations analyzed. The partitioning of molecular variance by analysis of molecular variance showed that most genetic variation resides within populations (68.85%). These results suggest that sexual reproduction is the predominant mode of reproduction forG. canariensegametophytic populations, and the main determinant in reaching high levels of genetic diversity. The Neighbor‐Joining tree and FCA analysis displayed two subclusters that correspond to the populations from the western islands (Tenerife, La Palma, Gomera) and the eastern island (Gran Canaria). In addition, we have detected a significant relationship betweenFST/(1−FST) and geographical distance consistent with data on water circulation and age of islands. The results obtained agree with an isolation by distance model, with gene flow from eastern to the western islands, and a high level of genetic differentiation between populations (FST=0.311,P<0.001).

Relationships between an Italian Strawberry Ecotype and its Ancestor using RAPD Markers

Random-amplified polymorphic DNA (RAPD) markers were used to evaluate genetic variability among populations of an Italian strawberry ecotype, and to determinate genetic relationships between genotypes and their putative ancestor. A total of 65 selections and one cultivar ‘Madame Moutot’ (MM), were analysed to evaluate genetic variability present in Etna mountain area and to confirm as MM was one of the cultivars that originated the ecotype. A total of 222 RAPD markers was obtained using 16 decamer primers and 6 longer primers, 90.8% of the markers obtained by selected primers resulted polymorphic at least within analysed genotypes. RAPDs were used to calculate genetic similarity coefficients and to generate dendrograms representing genetic relationships among genotypes analysed. Cluster analysis displays as RAPD polymorphisms were able to characterize the genotype variability among closely related groups. The data show as MM could be considered the ancestral genotypes introduced in that area. The results obtained confirm that RAPD markers could be used as reliable markers to perform phylogenetic studies in Fragaria×ananassa Duch. ex Rozier.

The extent of clonality and genetic diversity in the rare Caldesia grandis (Alismataceae): Comparative results for RAPD and ISSR markers

Genetic variation and clonal diversity of three natural populations of the rare, highly clonal marsh herb Caldesia grandis Samuelsson were investigated using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. Both of the markers worked effectively in clone identification of C. grandis. RAPD markers detected more diversity than ISSR markers in the three populations examined. Of the 60 RAPD primers screened, seven produced highly reproducible bands. Using these primers, a total of 61 DNA fragments were generated with 52 (85.25%) being polymorphic indicating considerable genetic variation at the species level. Analysis of molecular variance (AMOVA) showed that a large proportion of genetic variation (81.5%) resided within populations, while only a small proportion (18.5%) resided among populations. With the use of 52 polymorphic RAPD markers, we were able to identify 127 genets among 342 samples from three populations. The proportion of distinguishable genets (PD: mean 0.37), Simpson's diversity index ( D: mean 0.91), and evenness ( E: mean 0.78) exhibited high levels of clonal diversity compared to other clonal plants. These results imply that sexual reproduction has played an important role at some time during the history of these populations. Nevertheless, the high level of diversity could have been also partially generated from somatic mutations, although this is unlikely to account for the high diversity generally found among C. grandis genets.

A Partial Genetic Map of Stylosanthes Developed Using Inter-Specific F2 Cross

Low polymorphism in Stylosanthes emphasizes use of inter-specific crosses for the development of mapping population for genetic linkage map. Using 78 F2 individuals of the cross of S. scabra cv. Seca and S. fruticosa, 7 linkage groups were obtained when 81 polymorphic RAPD (Random Amplified Polymorphic DNA) markers were processed. Of these, 53 segregated in expected ratio of 3 : 1 for dominant marker in the F2 generation, 11 markers in 1 : 1 while 17 deviated from the expected ratio. Thirty markers remain unlinked. Total genome length covered by markers in the present partial map is 630.4 cM (centi Morgan) with an average interval of 39.4 cM. The skeleton map developed is being used to place reasonable numbers of RAPD and STS (Sequence Tagged Sites) markers and to identify QTLs (Quantitative Trait Loci) for anthracnose disease, one of the most important disease of the genus Stylosanthes.

Genetic diversity in camelina germplasm as revealed by seed quality characteristics and RAPD polymorphism

AbstractCamelina is an alternative oilseed crop species with limited information about the origin and diversity of available germplasm. Therefore, a set of 130 camelina accessions from a world collection was evaluated for oil content, protein content and 1000‐seed weight in field experiments grown in three macro‐environments in Austria. Based on phenotypic data, accessions were categorized into four groups with different seed characteristics using k‐means cluster analysis or principal component extraction. Subsequently, a representative set of 41 accessions was subjected to random amplified polymorphic DNA (RAPD) analysis. Of 24 primers, 15 were polymorphic producing a total of 30 marker loci. Genetic distance estimates between the 41 accessions were calculated, based both on RAPD polymorphism and on seed quality characteristics, and dendrograms were generated for comparison. Similarities were found between the two different clustering approaches, and grouping was partly in agreement with pedigree information or geographic origin. However, as the two estimates of diversity sampled different segments of the genome, i.e. regions coding for seed characteristics or phenotypically neutral genomic regions highlighted by discrete markers, the correlation between the two distance matrices was low.

Differentiation of Vaccinium Cultivars and Wild Clones Using RAPD Markers

The potential use of the random amplified polymorphic DNA (RAPD) technique for characterization and assessment of genetic relatedness was investigated in 13 wild cranberry (Vaccinium macrocarpon Ait) clones collected from Newfoundland and Labrador, Canada. RAPD markers were also used to distinguish representatives of three different Vaccinium species. Twenty-two decamer arbitrary primers yielded informative, reproducible and polymorphic banding patterns in 13 cranberry clones and produced a total of 134 bands, of which 114 were polymorphic. The UPGMA cluster analysis separated the clones into two main groups: Cluster I of seven and Cluster II of six with 0.62 to 0.91 and 0.50 to 0.77 Nei and Li’s similarity range, respectively. In another experiment, a subset of eight primers was used and the RAPD markers discriminated the three Vaccinium species: cranberry, lowbush blueberry (V. angustifolium Ait) and lingonberry (V. vitis-idaea L). The RAPD polymorphisms will be useful for Vaccinium genotype differentiation and the technology should be valuable for the maintenance of germplasm banks and the efficient choice of parents in the current Vaccinium germplasm improvement program.

Morphological and Molecular Characterization of Common Bean Landraces and Cultivars from the Caribbean

Little information is available regarding the relationship of Caribbean bean landraces with the Andean and Mesoamerican gene pools of common bean (Phaseolus vulgaris L.) While small‐seeded Mesoamerican black beans are prevalent in parts of the Caribbean, many of the regionally preferred red mottled and medium‐to‐large‐seeded bean landraces found there are postulated to belong to the Andean gene pool. To test this hypothesis, we analyzed the morphological characteristics, phenological traits, phaseolin status, and random amplified polymorphic DNA (RAPD) banding patterns of 54 red mottled or large‐seeded bean landraces and cultivars from the Caribbean (16 from the Dominican Republic, 14 from Haiti, 1 from Jamaica and 23 from Puerto Rico) compared with 11 Andean bean lines from other regions. To estimate phylogenetic relationships among the lines, distances were calculated and dendrograms constructed for morphological and/or phenological and molecular characteristics by the complete clustering method. The landraces were grouped into two clusters morphologically: one with Mesoamerican characteristics, which included all the red mottled lines from Haiti and three landraces from the Dominican Republic collected near the Haitian border and the other with Andean characteristics, which included all the lines from Puerto Rico and the remaining lines from the Dominican Republic. RAPD and phaseolin polymorphisms identified three groups, one corresponding to the genotypes with Mesoamerican morphologies, one to those with Andean morphologies, and another that had Andean phenotypes but proximity to the Mesoamerican group, suggesting possible introgression between the gene pools. Phaseolin variability agreed with other molecular and morphological data allowing the assignment of genotypes to a Mesoamerican or Andean gene pool. Knowledge of this variability may provide useful information concerning the potential value of Caribbean landraces to Andean bean breeding programs.

Relationship between Origin and Genetic Diversity in Chinese Soybean Germplasm

The soybean [Glycine max (L.) Merr.] was domesticated in China. Information about the amount and distribution of genetic diversity in China is critical to effective soybean germplasm management. Information is currently available from only a few provinces in China. The objectives of this research are to estimate the genetic variation within and among four geographically diverse provinces (Zhejiang, Sichuan, Gansu, and Hebei) in China and to determine the relationship between geographical origin and genetic diversity. Ten primitive cultivars from each province were characterized by random amplified polymorphic DNA (RAPD) fragments produced from 31 selected decamer primers. CNS, an important U.S. ancestral line, was also included as a control. Genetic variation was estimated by AMOVA analysis with 125 polymorphic RAPD fragments. Genetic distances were calculated by means of Jaccard's coefficient and expressed as dissimilarity coefficients. Unweighted paired group method using arithmetic averages (UPGMA), Ward's minimum‐variance method, VARCLUS, and multidimensional scaling (MDS) were applied to define the genetic relationships. AMOVA identified significant genetic differences between all pairs of provinces except between Zhejiang and Sichuan. The greatest difference was observed between Hebei and Zhejiang. There was disagreement among the clustering methods, but each procedure identified clusters of accessions that originated from the same province. Based on data from all clustering procedures, six major clusters containing a total of 32 accessions were defined with each cluster dominated by accessions from a single province. These data provide additional evidence that primitive cultivars of China were generally genetically isolated in relatively small geographical areas.

Genetic Heterogeneity of the Tropical Abalone (Haliotis asinina) Revealed by RAPD and Microsatellite Analyses

Genetic heterogeneity of the tropical abalone, Haliotis asinina was examined using randomly amplified polymorphic DNA (RAPD) and microsatellite analyses. One hundred and thirteen polymorphic RAPD fragments were generated. The percentage of polymorphic bands of H. asinina across overall primers was 85.20%. The average genetic distance of natural samples within the Gulf of Thailand (HACAME and HASAME) was 0.0219. Larger distance was observed when those samples were compared with HATRAW from the Andaman Sea (0.2309 and 0.2314). Geographic heterogeneity and F(ST) analyses revealed population differentiation between H. asinina from the Gulf of Thailand and the Andaman Sea (p < 0.0001). Three microsatellite loci (CUHas1, CUHas4 and CUHas5) indicated relatively high genetic diversity in H. asinina (total number of alleles = 26, 5, 23 and observed heterozygosity = 0.84, 0.42 and 0.33, respectively). Significant population differentiation was also found between samples from different coastal regions (p < 0.0001). Therefore, the gene pool of natural H. asinina in coastal Thai waters can be genetically divided to 2 different populations; the Gulf of Thailand (A) and the Andaman Sea (B).

Segregation patterns of several morphological characters and RAPD markers in interspecific hybrids between Dianthus giganteus and D. carthusianorum

The segregation ratio of morphological characters (15 quantitative and 4 qualitative) and random amplified polymorphic DNA (RAPD) markers in 55 interspecific hybrids between Dianthus giganteus and D. carthusianorum and their parents were studied. Interspecific hybrids exhibited either intermediate characteristics between parents shorter, fewer characteristics than parents except for stem length and height of corolla where heterosis was found. Segregation of four qualitative characters such as profile of the lower part of the corolla, stigma color, the main secondary color of petal blade, and arrangement of individual flowers, were exhibited as either characteristics of female parent or male parent. Two hundred and sixteen polymorphic RAPD bands detected in 55 interspecific hybrids were divided into four types: AB type (both-parental type) which was presented in both female parent and male parent, Ab type (female parental type) which was presented in only female parent, aB type (male parental type) which was presented in only male parent, and ab type (non-parental type) which was presented in only hybrids except their parents. The number of AB, Ab, aB, and ab type bands were 33 (15.3%), 56 (26.0%), 50 (23.1%), and 77 (35.6%), respectively. The proportion of parental type bands to non-parental type bands was two to one and only 54.6% of four type bands coincided with expected ratio.

Conservation Genetics of Mexican Beech, Fagus grandifolia var. mexicana

Fagus grandifolia var. mexicana(Fagaceae) is a Mexican endemic tree, currently threatened with extinction. In order to assess the level and structure of genetic variation in four remaining populations, leaf samples were analysed using random amplified polymorphic DNA (RAPD) and cpDNA PCR-RFLP markers. A sample of the more widespread congener, F. grandifoliavar. grandifolia from the USA was also analysed for comparison. Thirty-three polymorphic RAPD bands were produced using 18 10-mer primers. AMOVA of RAPD data indicated significant (P < 0.002) population differentiation, with 15.6% of variation recorded between Mexican populations. PCR-RFLP analysis enabled three cpDNA haplotypes to be identified, denoted types A, B, and C. Types A and B were each restricted to an individual Mexican population, whereas Type C was fixed for two Mexican populations, and the population from the USA. Within-population genetic variation, quantified as percentage polymorphic bands, Shannon's Diversity Index and Nei's gene diversity measure, was found to be lower in Mexican populations than in that from the USA, and was positively related to population size. These results suggest that an unexpectedly high degree of genetic variation exists within Mexican beech, and this variation should be considered in developing the conservation strategy that is urgently required if extinction of this taxon is to be prevented.

Genetic Diversity Among Finnish Six-Rowed Barley Cultivars Based on Cpedigree Information and DNA Markers

Genetic diversity among Finnish six-rowed spring barleys was studied by both pedigree analysis and random amplified polymorphic DNA (RAPD) markers. 26 six-rowed barley varieties have been released by Finnish plant breeders, 22 of which are based on controlled crosses. These 22 varieties originate from 14 ancestors, of which 7 (Olli, Asplund, Vega, Gull, Hanna, Maskin, OAC21) are principal ancestors with a coancestry r 0.05. Contribution of the principal ancestors to the pedigrees of the varieties has not changed significantly during the 60 years of barley breeding in Finland. Jaccard's similarity indices, based on 54 polymorphic RAPD markers, were calculated for a set of modern, ancestral and introgression lines and varieties. Jaccard's indices varied from 0.154 to 0.935, and similarities between related accessions were significantly higher (t-test, P 0.01) than between the unrelated ones. Correlation between kinship coefficients based on pedigrees and Jaccard's indices were weak, and Jaccard's indices varied widely for accessions without a known pedigree. The genetic similarity within the old varieties is comparable to that of the modern varieties.

RAPD Variations in Selected and Unselected Blue Grama Populations

Blue grama (Bouteloua gracilis H.B.K. Lag. ex Steud.) is one of the most widespread native grasses in western North America. Little is known about the genetic diversity of this species and the genetic shift in selected populations. Random amplified polymorphic DNA (RAPD) markers were used to assess the genetic variations of blue grama plants in 11 natural source populations (SPs) in southern Manitoba and two selected populations. Population ‘BMSC’ was a balanced multisite composite of 99 clones selected for higher seed yield from the 11 SPs. Population ‘MSC’ was a mass‐selected composite of 25 clones with higher seed yield from eight SPs. Twelve RAPD primers were used to assay 108 original propagules from the 11 SPs and 96 seedlings from each selected population. A total of 69 polymorphic RAPD bands were detected. No unique RAPD bands were found for any SPs and 97.8% of the total RAPD variation was detected within SPs. Variation in RAPD markers was not associated with geographical distances. Highly significant changes in RAPD band frequency from their SPs were detected in both selected populations, but only MSC displayed the fixation of polymorphic bands. The estimated genetic shifts were small, 0.6% for BMSC and 1.9% for MSC.

RAPD Analysis of 54 North American Flax Cultivars

Broadening the genetic base of linseed flax (Linum usitatissimum L.) cultivars to sustain improvement requires assessment of genetic diversity available in flax germplasm. The objective of this study was to analyze the genetic variation, genetic erosion, and genetic relationship of 54 North American flax cultivars by means of random amplified polymorphic DNA (RAPD) markers. The variations observed at the 84 polymorphic RAPD loci were relatively moderate with respect to primer, polymorphism, and cultivar. The proportions of fixed recessive RAPD loci for all the cultivars ranged from 36.9 to 59.2%, with an average of 45.3%. Genetic erosion in the century‐long breeding programs was not statistically significant as revealed by the proportion of fixed recessive RAPD loci, but the trend appeared to be that 2.5% of variable RAPD loci were fixed over 100 yr. While some variable RAPD loci were fixed over different breeding periods, the genetic relatedness of the cultivars was reduced in the Canadian programs, but not in the U.S. programs. The genetic relationships of the cultivars inferred via RAPD similarity were largely consistent with known, but incomplete, pedigrees. Both Canadian and U.S. cultivars were intermixed in various groups without distinct separation and several genetically distinct cultivars (i.e., NDR 52, Vimy, Rocket, Norland, Dakota, and Marine) were identified.

Genetic differentiation of Aedes aegypti (Diptera: Culicidae), the major dengue vector in Brazil.

In 2000, Brazil reported 180,137 cases of dengue, approximately 80% of the total in the Americas. However, little is known about gene flow among the vector populations in Brazil. Random amplified polymorphic DNA (RAPD) was used to study the genetic structure of Aedes aegypti in 15 populations from five states, with a range extending 2,800 km. An analysis of 47 polymorphic RAPD loci estimated gene flow at the macro- (different states) and micro- (different cities) geographical levels. Genetic polymorphism was high (H(S) = 0.274), and high levels of genetic differentiation existed both between different states (G(ST) = 0.317) and between cities or neighborhoods in each state (G(ST) = 0.085-0.265). These values are higher than those described for any other populations of A. aegypti.