Proportion Of Polymorphic Bands Research Articles

Genetic Diversity and Population Structure Analysis of 10 Species of Ranunculaceae by Inter-Simple Sequence Repeats Markers

To analyze genetic diversity in 10 species of Ranunculaceae. The genetic diversity and genetic structure of 10 species of Ranunculaceae in 22 populations in Luoyang and surrounding areas were analyzed using primers selected by ISSR molecular markers. The 12 selected primers amplified a total of 116 clear bands, and the proportion of polymorphic bands was 98.1%. The average polymorphism information content (PIC) of the primers was 0.9478. The results of genetic diversity analysis showed that the Shannon information index (I) of 22 populations of Ranunculaceae plants was 0.4367±0.1904, and Nei’s genetic diversity index (H) was 0.2807±0.1481. The above results showed rich polymorphism in all 12 primers, and very rich genetic diversity in the 10 species of Ranunculaceae from 22 populations. The gene flow Nm was 0.3096 and genetic differentiation index Gst was 0.5997, indicating that genetic differentiation mainly derived from diversity within populations, with less gene communication among populations. The Mantel test showed positive correlation between genetic distance and geographical distance (r = 0.2530, P < 0.01). Cluster analysis, principle coordination analysis (PCoA) and population cluster analysis yielded broadly consistent clustering results showing that individuals of the same germplasm were closely related, tending to be clustered into one group first; the second grouping was arranged according to the geographical distance. The genetic diversity of 10 species of Ranunculaceae in 22 populations is very rich. The variation among 22 populations is large, which indicates that the 10 species of Ranunculaceae have a strong ability to adapt to the environment. The combination of the three methods can improve the accuracy of cluster analysis of wild Ranunculaceae samples. This study lays the foundation for rational utilization and resource management of Ranunculaceae.

Cytomorphological and genetic indicators in the early ontogenesis of the wild and farmed broad whitefish (Coregonus nasus)

The qualitative and quantitative composition of primordial germ cells (PGCs) and the genetic variability of embryos of the Coregonus nasus from the Ob river basin and domesticated population breeding outside the natural areal was examined. In the broad whitefish, typical, binuclear, polymorphic nuclei cells, as well as PGCs represented primary gonocytes during embryogenesis in clusters. When hatching larvae PGCs mitoses were noted only in domesticated juveniles. The genetic variability of embryos of the broad whitefish was studied by polymerase chain reaction of inter simple sequence repeats (ISSR-PCR). The high polymorphism of the broad whitefish cultured population was revealed. The proportion of polymorphic bands was 89.4%, Nei's genetic diversity was 0.32. Reproduction of the domesticated broad whitefish did not affect the overall level of polymorphism of neutral DNA markers. These findings suggest the preservation of cytomorphological and genetic diversity in C. nasus embryo from different sources.

Genetic Diversity of Elaeagnus angustifolia L. (Elaeagnaceae) Populations in İzmir (Turkey)

This study was performed out genetic diversity of some Elaeagnus angustifolia L. populations growing in İzmir province by using ISSR markers. In the study, PCR was performed using 15 ISSR primers. PCR products were run in agarose gel and visualized under UV light. Amplified products were scored as follows. A total of 46 bands were produced from 15 ISSR primers, of which 27 were polymorphic. The proportion of polymorphic bands was evaluated as approximately 58.7%. Genetic distances between phylogenetic trees and genotypes were calculated using the PAUP program. The phylogenetic tree consists of two large clades. The longest distance between populations was between Gümüldür-Özdere and Çeşme-Alaçatı population with a value of 0.50, while the closest distance was between Çeşme-Ayayorgi and Konak-Hatay populations with a value of 0.06. The results show that ISSR markers are useful tools for determining genetic relationships between E. angustifolia populations

ISSR polymorphism of laying hens of broiler parental stock distinguished by rates of growth and productivity indicators

Searching for biomarkers of high productivity in chickens is currently one of the relevant tasks facing poultry farming. Thus, the research was aimed at studying genetic traits of laying hens. The hens belonged to parental stock of the «Arbor Acres Plus» hybrid cross and varied according to the productivity abilities. The study was carried out in 2018-2019 at the PRODO Tyumen Broiler factory located in Tyumen, Tyumen region on three groups of chickens numbering from 6000 to 6085 bird units. Raising and evaluation of laying hens were carried out in accordance with the «Arbor Acres Plus» guidelines and standards for breeding of the parental generation and the regulations for the technology of the parent stoсk management and bird weighing which were developed on the basis of those guidelines and standards and adopted at the factory. The practice of raising the «Arbor Acres Plus» hybrid cross revealed a distinct differentiation of laying hens by body weight during the growth period. There were distinguished fast-growing «large» individuals, «small» individuals and «medium» individuals occupying an intermediate position. At the beginning of the experiment, during the 18th week of age the average mass of «small» chickens was 106 g less than that of chickens from the «medium» group. The average mass of chickens from the «medium» group was 139 g less than the indications in the «large» group, and the differences between the «large» and the «small» hens amounted to 245 g. Such differences remained until the 35th week, and then they leveled out substantially. The differences between groups of chickens were observed also in egg production rates, which decreased with increasing the age of laying hens (by 31-33 weeks). The amount of eggs per layer per week averaged out at 71.1 % for “small” hens, 72.8 % for the «medium», and 74.4 % for the «large» ones. To assess the genetic polymorphism of chickens the ISSR-PCR method was applied. Seven primers were used to study the genetic polymorphism of laying hens: (AG)8G, (AG)8T, (CA)8G, (GT)8C, (AC)8T, (TC)8C, (TG)8A. The experimental groups of laying hens differed both in the frequencies of ISSR bands and in the average indicators of polymorphism. Higher parameters of the proportion of polymorphic bands (P), genetic diversity (h), apparent (ne) and effective number of alleles (na) were observed in the group of «large» laying hens, while the «medium» and «small» groups had lower rates and did not significantly differ in the level of polymorphism among themselves. Higher rates of ISSR polymorphism observed in the group of fast-growing («large») laying hens could be a marker of a higher level of genetic diversity in this group compared to chickens from the other two groups. The conducted studies showed that ISSR markers can be recommended as a simple tool for monitoring the genetic diversity of stocks of laying hens.

Analysis of genetic diversity of soybean germplasm from five different origins using RAPD markers

ABSTRACTThe pattern of genetic diversity among 92 genotypes of soybean from 5 different origins/sources (Pakistan, the USA, Asian Vegetable Research Development Centre (AVRDC), Japan and North Korea) was analyzed using randomly amplified polymorphic DNA markers. Out of 20 random primers 6 tested, 10 were polymorphic among genotypes and they yielded 107 markers, with an average of 10.7 markers per primer. The proportion of polymorphic bands within genotypes ranged from 0.47 to 0.71 with an average of 0.59. Pakistani and US genotypes exhibited the highest number of polymorphic bands (95%), while North Korean genotypes revealed the lowest (60%). The mean band frequency of the primers among genotypes was 0.57 with a range of 0.08–0.99. The Shannon’s index and Nei’s genetic diversity index revealed that primer OPF-06 showed maximum genetic diversity among the genotypes. Dendrogram constructed using Unweighted Pair Group Mean Average (UPGMA) method divided the genotypes into 5 main groups consisting of 13 clusters. The results of cluster analysis indicated that the genetic diversity between Pakistani and US or AVRDC genotypes is much larger than that between Pakistani and North Korean or Japanese genotypes. The Pakistani genotypes had distinct bands from plant introductions. Therefore, the Pakistani genotypes may be useful to soybean breeders.

희귀수종 먹넌출 엽의 형태적 특성과 유전변이

우리나라에서 안면도에만 분포하는 먹넌출 집단의 생명자원보존을 위하여 엽의 형태적 특성과 I-SSR 표지자를 이용한 유전변이를 조사하였다. 10가지 엽특성에 대한 ANOVA 분석결과 모든 특성에서 개체 간에 통계적인 유의성이 인정되었다. 조사된 39개체의 평균특성은 엽신장 11.8 cm, 최대엽폭 7.1 cm, 엽지수 1.67, 상1/3폭 5.4 cm, 하1/3폭 6.2 cm, 엽병길이 3.6 cm, 엽두께 0.19 mm, 엽맥수(좌) 11.5개, 엽맥수(우) 11.4개, 엽면적 61.7 <TEX>$cm^2$</TEX>로 나타났다. 변이계수 값은 엽두께, 엽병길이, 엽면적이 각각 18.8%, 21.7%, 22.0%로 높게 나타났으며, 나머지 특성들에서는 15% 이내의 비교적 낮은 변이를 나타냈다. 선발된 8개 I-SSR Primer에서 총 50개의 증폭산물을 얻었으며, 유효대립 유전자의 수 1.719개, 다형적 유전자좌의 비율 26.0%, 이형접합도의 기대치 0.410 및 Shannon의 다양성지수 0.598로 각각 나타났다. 안면도 먹넌출 집단은 제한된 지역에 분포하며 개체수가 적음에도 불구하고 높은 유전다양성을 유지하는 것으로 나타났다. This study was conducted to investigate the morphological characteristics of leaf and the genetic diversity of Berchemia racemosa var. magna which is only found in Anmyeon Island of South Korea. ANOVA test showed that there were significant differences among individuals within population in all 10 leaf characteristics. Average characteristics of 39 individuals were 11.8 cm in leaf length, 7.1 cm in leaf width, 1.67 in leaf index, 5.4 cm in upper 1/3 width, 6.2 cm in lower 1/3 width, 3.6 cm in petiole length, 0.19 mm in leaf thickness, 11.5 ea. in number of veins (left), 11.4 ea. in number of veins (right) and 61.7 <TEX>$cm^2$</TEX> in leaf area, respectively. Except for leaf thickness (18.8%), petiole length (21.7%) and leaf area (22.0%), the coefficients of variation of most leaf characteristics were relatively low (<15.0%). A total of 50 bands was generated from 8 selected I-SSR primers. The estimates of genetic variation were 1.719 in effective number of alleles (<TEX>$A_e$</TEX>), 26.0% in proportion of polymorphic bands (P), 0.410 in expected heterozygosity (<TEX>$H_e$</TEX>) and 0.598 in Shannon's diversity index (S.I.), respectively. In spite of the small number and the limited distribution, the B. racemosa var. magna population in Anmyeon Island showed high genetic diversity.

High Genetic Diversity and Insignificant Interspecific Differentiation inOpisthopappusShih, an Endangered Cliff Genus Endemic to the Taihang Mountains of China

Opisthopappus Shih is endemic to the Taihang Mountains, China. It grows in the crevice of cliffs and is in fragmented distribution. This genus consists of two species, namely, O. taihangensis (Ling) Shih and O. longilobus Shih, which are both endangered plants in China. This study adopted intersimple sequence repeat markers (ISSR) to analyze the genetic diversity and genetic structure from different levels (genus, species, and population) in this genus. A total of 253 loci were obtained from 27 primers, 230 of which were polymorphic loci with a proportion of polymorphic bands (PPB) of up to 90.91% at genus level. At species level, both O. taihangensis (PPB = 90.12%, H = 0.1842, and I = 0.289) and O. longilobus (PPB = 95.21%, H = 0.2226, and I = 0.3542) have high genetic diversity. Their respective genetic variation mostly existed within the population. And genetic variation in O. longilobus (84.95%) was higher than that in O. taihangensis (80.45%). A certain genetic differentiation among populations in O. taihangensis was found (G st = 0.2740, Φst = 0.196) and genetic differentiation in O. longilobus was very small (G st = 0.1034, Φst = 0.151). Gene flow in different degrees (N m = 1.325 and 4.336, resp.) and mating system can form the existing genetic structures of these two species. Furthermore, genetic differentiation coefficient (G st = 0.0453) between species and the clustering result based on the genetic distance showed that interspecific differentiation between O. taihangensis and O. longilobus was not significant and could occur lately.

설악산 눈잣나무 천연집단의 침엽특성과 유전변이

설악산 눈잣나무 천연집단은 국내 유일하게 분포하는 남방한계 분포지 수종으로 유전자원보존을 위하여 침엽의 형태적 해부학적 특성과 I-SSR 표지자를 이용한 유전변이를 조사하였다. 8가지 침엽특성에 대한 ANOVA 분석결과 모든 특성에서 개체 간에 통계적인 유의성이 인정되었다. 조사된 66개체의 평균특성은 침엽길이 53.59 mm, 침엽폭 0.78 mm, 침엽지수 68.98 및 침엽두께 0.65 mm, 최대기 공열수 4.56개, 최소기공열수 3.80개, 전체기공열수 8.36개 및 수지구수 1.71개로 각각 나타났다. 특히, 수지구는 모두 바깥쪽에 위치하는 외위 형태의 1~3개 범위로 수지구 2개 유형이 69.47%을 나타낸 반면 1개 유형은 30.45%를 나타냈다. 선발된 9개 I-SSR Primer에서 총 78개의 증폭산물을 얻었으며, 다형적 유전자좌의 비율은 61.5%, 유효대립유전자의 수 1.698개, 이형접합도의 기대치 0.388 및 Shannon의 다양성지수 0.567로 각각 나타났다. This study was conducted to investigate the morphological and anatomical characteristics of needle and the genetic diversity of Pinus pumila Regel which is a unique and the southern peripheral population in South Korea. ANOVA test showed that there were significant differences among individuals within population in all 8 needle characteristics. Average characteristics of 66 individuals were 53.59 mm in needle length, 0.78 mm in needle width, 68.98 in needle index, 0.65 mm in needle thickness, 4.56 ea. in maximum stomata row, 3.80 ea. in minimum stomata row, 8.36 ea. in total stomata row and 1.71 ea. in resin canals, respectively. Resin canal per needle of this species ranged from one to three, depending on external type. Especially, arrangement types were 69.47% in two resin canals and 30.45% in a single resin canal. A total of 78 bands was generated from 9 selected I-SSR primers. The estimates of genetic variation were 61.5% in proportion of polymorphic bands (P), 1.698 in effective number of alleles (<TEX>$A_e$</TEX>), 0.388 in expected heterozygosity (<TEX>$H_e$</TEX>) and 0.567 in Shannon's information index (S.I.), respectively.

Increased genetic differentiation but no reduced genetic diversity in peripheral vs. central populations of a steppe grass

Intraspecific genetic variation is essential for the performance and evolution of species. Populations at a species' geographic range periphery receive considerable attention in biogeography and conservation because they are smaller and spatially more isolated than central populations, a pattern expected to lead to higher genetic differentiation and lower within-population genetic diversity. We tested these predictions in central and peripheral populations of the Eurasian steppe grass Stipa capillata. We analyzed AFLP fingerprint patterns in 319 individuals from 20 large and abundant populations in the core, in Kazakhstan, and 23 small and isolated populations at the periphery, in Central Europe. We calculated different genetic diversity estimates and assessed genetic differentiation among populations by examining F(ST) values, a neighbor-net network, and an AMOVA. As expected, genetic differentiation among populations was significantly larger at the range periphery (F(ST) = 0.415) than in the range core (F(ST) = 0.164). In contrast to predictions, however, we found similarly low genetic diversity within central (proportion of polymorphic bands = 21.9%) and peripheral (20%) populations. Higher genetic differentiation in the small and spatially isolated peripheral populations is likely driven by genetic drift and reduced gene flow due to a complex landscape structure and the abandonment of traditional management regimes. With regard to unchanged genetic diversity, it appears that life-history traits like longevity or sufficiently large population sizes could allow S. capillata to escape deleterious effects at the range edge.

Genetic variation in remnant Festuca hallii populations is weakly differentiated, but geographically associated across the Canadian Prairie

AbstractGenetic diversity is essential for predicting plant evolutionary potential and for formulating conservation strategies. However, little is known about the genetic variation of plains rough fescue [Festuca hallii (Vasey) Piper], a widespread and diagnostic grass in the Fescue Prairie. We used the amplified fragment length polymorphism (AFLP) technique to assess the genetic variation of 30 fragmented populations of F. hallii across the northern Canadian Prairie and its associations with 12 geographical, fragmentation and environmental attributes. Three AFLP primer pairs were used to screen 840 samples, representing approximately 30 samples from each population, and 246 polymorphic bands were scored. The fescue plant was genetically diverse, as revealed by the proportion of polymorphic bands (0.870–0.967), the mean band frequency (0.364–0.457) and the within‐population variation (69.4–85.4). The genetic variation was not highly differentiated, with only 6.5% of the total AFLP variation residing among populations. A Mantel test revealed a significant correlation between genetic and geographical distances (r = 0.39; P &lt; 0.004) and a spatial autocorrelation up to 60 km among populations was detected. The AFLP variation displayed a longitudinal decline and was significantly associated with environmental attributes related to moisture, indicating local adaptation. However, the AFLP variation was not significantly associated with the estimated population size and geographical distance to the nearest neighbor, suggesting that fragmentation has not generated considerable genetic impact on the fescue populations. Implications for fescue conservation, restoration and management are discussed.

QTL mapping of agronomic traits using an RIL population derived from a cross between temperate japonica cultivars in rice (Oryza sativa L.)

To employ molecular marker-aided selection for developing japonica rice (Oryza sativa L.) cultivars with high yielding potential and good eating quality, we carried out QTL analysis for agronomic and grain traits using 231 recombinant inbred lines (RIL) from a cross between two temperate japonica cultivars, Suweon365 and Chucheongbyeo. A linkage map with 221 loci, including 134 simple sequence repeats (SSRs), 66 amplified fragment length polymorphisms (AFLPs), and 21 miniature inverted repeat transposable elements (MITEs)-anchored markers, was constructed covering 2,227 cM of the twelve rice chromosomes, with an average distance of 11.0 cM between markers. The proportion of polymorphic bands between parents averaged 19.5%, 12.9% and 42.3% for SSRs, AFLPs and MITEs, respectively. Construction of maps without AFLP or MITE markers indicated that expansion of this map is due to the incorporation of AFLP markers, and this result is consistent with previous reports. Twenty-seven QTLs for ten traits were identified over two years, and fourteen were consistently detected in two consecutive years. When the locations of each QTL detected in this study were compared with those in previous QTLs studies, eight QTLs for culm length, spikelets per panicle and, thickness, length and shape of grain, had not been reported in previous mapping studies, indicating potentially novel alleles of japonica rice. Interestingly, a cluster of seven QTLs, including heading date and grain morphology traits, was detected on the long arm of chromosome 7. The markers linked to these QTLs would be valuable in a marker-assisted breeding program for japonica cultivars.

Inverse Sequence-tagged Repeat (ISTR) Analysis of Genetic Variability in Forest Coffee (Coffea arabica L.) from Ethiopia

Genetic diversity in forest coffee (Coffea arabica L.) was estimated using inverse sequence-tagged repeat (ISTR) markers. One hundred ninety two samples representing 16 populations of C. arabica from four regions of Ethiopia were analyzed with 12 pairs of forward and backward ISTR primer combinations. A total of 144 reproducible bands were generated out of which 37 (25%) were polymorphic and scored as present (1) or absent (0) data matrix. This data was used to compute Jaccard coefficient to estimate genetic variability among all possible pairs of samples. The proportion of polymorphic bands within populations ranged from 19% for Bale-3, to 54% for Walega-2 populations. Un-weighted pair group method with arithmetic mean (UPGMA) based cluster analysis generated two clusters at 56% similarity value. The samples were clustered on the basis of their geographical origin, which could be attributed to a few region specific banding patterns detected. However, within regions most of the samples failed to cluster on the basis of their respective populations, which may be due to the presence of substantial gene flow between local populations in the form of seedlings carried out by farmers. The results may provide information to develop strategies for in situ conservation.

Genetic Diversity of Vegetable Water Pepper (Persicaria hydropiper (L.) Spach) as Revealed by RAPD Markers

The genetic diversity and genetic relationships of three cultivated varieties (benitade, aotade and ayutade) and a wild race of water pepper, Persicaria hydropiper, were analyzed using RAPD markers. The proportion of polymorphic bands and Shannon’s index of phenotypic diversity within accession in five benitade and two aotade accessions were distinctly lower than those in six wild water pepper accessions, suggesting the presence of a decline in genetic diversity within accession in the cultivated varieties under cultivation. A neighbor-joining (NJ) tree for nine cultivated and 38 wild accessions indicated the incidence of the independent domestication of the three cultivated varieties, benitade, aotade and ayutade, from wild water pepper. The NJ tree of the individual plants for five benitade accessions revealed the presence of close relationships among the accessions, but also showed a slight divergence in the accessions from different locations.

Genetic variation within the endangered species Aldrovanda vesiculosa (Droseraceae) as revealed by RAPD analysis

Aldrovanda vesiculosa L. (Droseraceae) is an endangered aquatic carnivorous plant species inhabiting standing dystrophic waters across Europe, Asia, Australia, and Africa. Despite its widespread occurrence, its population is patchily distributed. Proliferation in these mostly isolated habitats is largely clonal by shoot branching. We assessed the level of variation of random amplified polymorphic DNAs (RAPDs) in a collection of plants from Europe, Asia, and Australia to study the distribution of genetic variation. The low level of genetic variation found in a previous allozyme study was confirmed in that only 14% of 151 RAPD primers gave polymorphic banding patterns. The proportion of polymorphic bands over all primers was 37% with a mean Jaccard distance of 0.62. Cluster analysis and ordination analysis identified three clusters of closely related plants: an Australian and Japanese accession, a Ukrainian, Russian, and Rumanian accession, and a third accession from Poland and Germany. Although the plants from Germany and NW Australia did not differ from other members of the same RAPD cluster on the basis of morphological or physiological characteristics, these plants were clearly of recombinant origin based on the results of compatibility tests. Remaining accessions possessed RAPD patterns consistent with predominantly asexual mode of reproduction. By focussing on the modes of reproduction in combination with physiological and morphological features, the RAPD analyses can be used for restoration strategies of endangered plant species.

Patterns of genetic variation in Pinus chiapensis, a threatened Mexican pine, detected by RAPD and mitochondrial DNA RFLP markers.

Pinus chiapensis (Pinaceae) is a large conifer, endemic to central and southern Mexico and north-western Guatemala. In order to assess the extent of genetic variation within and between populations of this species, samples were obtained from throughout the natural range and analysed using random amplified polymorphic DNA (RAPD) and mtDNA RFLPs markers. Probes for the CoxI mitochondrial gene enabled two mitotypes to be observed. Populations from the eastern and western limit of the range of the species were fixed for one mitotype ('A'), whereas two populations distributed near the centre of the range were fixed for another ('B'). When the samples were screened with eight 10-mer RAPD primers, a total of 12 polymorphic bands were detected. The proportion of polymorphic bands was unusually low (24.5%) compared with other tree species. AMOVA analysis indicated that a significant proportion of the variation (P < 0.002) was distributed between populations; the extent of population differentiation detected (Phi(st) = 0.226; G(ST ) = 0.194) was exceptionally high for a pine species. Pair-wise comparison of Phi(st) values derived from AMOVA indicated that populations were significantly (P < 0.05) different from each other in virtually every case. These results are interpreted in the context of the evolutionary history of the species, and the implications for its in- and ex situ conservation are discussed.

Comparison of ISSR and RAPD markers to characterize three Chilean Nothofagus species.

The present study is the first report of fingerprinting on three Chilean Nothofagus species using ISSR and RAPD markers; 61 Nothofagus nervosa, 32 Nothofagus obliqua and 32 Nothafagus dombeyi individual trees, sampled from collection and natural sites, were analyzed. Among 45 primers tested, the 6 ISSR and 6 RAPD primers selected for the analysis generated a total of 63 ISSR and 42 RAPD fragments. A high proportion of polymorphic bands, ranging from 97% and 80%, was found using both markers. A similar number of private and marker bands was generated by both markers in all the species examined and one discriminant ISSR fragment was obtained for N. dombeyi. Jaccard and Dice similarity indices were used to evaluate pairwise genetic divergence; cluster analysis of the similarity matrices was performed to estimate the intra- and inter-specific genetic diversity, and PCA analysis was employed to evaluate the resolving power of the markers to differentiate between the species. These analyses, carried out for both markers, allowed us to identify three main groups corresponding to the three Nothofagus species. The results of the present study can be seen as a starting point for future researches on the population and evolutionary genetics of these species.

Natural and culture-induced genetic variation in plantains (Musa spp. AAB group)

Random amplified polymorphic DNA (RAPD) analysis of 15, mostly African, plantain land races revealed a very low proportion of polymorphic bands (13 of 276). However, further examination of these 13 marker bands demonstrated that they varied within land races and could not be used to distinguish between land races. In many cases, this could be directly associated with tissue culture treatment of the material. In order to investigate tissue culture effects in more detail, a single meristem of the West African plantain Agbagba was introduced into axenic culture and subjected to three cycles of micropropagation. A total of 48 regenerated plants were established under field conditions and subjected to RAPD analysis. By using 40 arbitrarily selected primers, about 400 bands were scored across this population of in vitro-derived plants. Sixteen of the bands were polymorphic within the population of Agabgba plants, distinguishing 13 genotypes. The pattern of relationships of these genotypes was established by cluster analysis; field characterisation of the plants supported the relationships revealed by RAPD data. The high level of RAPD polymorphism (4% of bands polymorphic), along with a clear correlation between the genotypic classification of individual plants and their tissue culture pedigree, suggests that a substantial amount of genetic variation existed within the original cultured meristem. On this basis, a putative Agbagba meristem representing an apparent sectoral chimera has been constructed. A model is presented that takes account of the persistence and high rate of somaclonal variation and proposes that the mother Agbagba plant comprised a periclinal chimera.

Genetic variation between strains of the Mediterranean fruit fly, Ceratitis capitata, detected by DNA fingerprinting.

DNA fingerprinting has been used to detect genetic variation in the Mediterranean fruit fly, Ceratitis capitata. Three different probes have been identified that can be used to detect DNA restriction fragment length polymorphisms between strains of this species. The strains used in this study differ only in terms of their geographic origin or genetic background. One of the probes used is the bacteriophage vector M13, and the other two are repetitive sequences derived from the medfly genome based on a weak homology to M13. Within a strain, each probe produces a consistent restriction fragment profile that is not affected by the method or timing of DNA extraction. Between strains, when M13 is used as a probe, an average of 10% of the observable bands are polymorphic. Use of the medfly genomic sequences as a probe increases the proportion of polymorphic bands between strains up to 30%. The fact that genetic differences between even such closely related strains can be reliably detected by this method holds great promise for studies of insect pests including the ability to monitor the movements of pest species, determining the extent of genetic variation in pest populations, and in making identifications from otherwise unidentifiable material.