Population structure and interspecific differentiation of the peat moss sister speciesSphagnum rubellum andS. capillifolium (Sphagnaceae) in northern Europe

Isozyme electrophoresis was used to study the morphologically similar sister speciesSphagnum rubellum andS. capillifolium from a sample of 1313 plants representing 37 populations from Scandinavia, Great Britain and S Germany. The mean pairwise genetic identities (I) among conspecific populations were 0.976 forS. rubellum and 0.969 forS. capillifolium, versus 0.627 between populations of the two species. Interspecific gene flow was indicated by the observation of occasional plants in sympatric populations with alleles otherwise unique to the other species. Populations of bisexualS. capillifolium were significantly more variable than populations of unisexualS. rubellum. Alpine populations ofS. rubellum andS. capillifolium were dominated by few genotypes, and differentiation among populations was pronounced, indicating a low level of sexual recombination. InS. rubellum, maximum variability was found in western areas with high annual precipitation. Distribution of alleles inS. rubellum indicated restricted gene flow between Great Britain and Scandinavia. Postglacial migration from separate refugia may explain large-scale variation inS. rubellum.     

Patterns of variation in morphological characters and isoenzymes in populations of Sphagnum capillifolium (Ehrh.) Hedw. and S. rubellum Wils. from two bogs in southern Sweden

Abstract

Isoenzymatic and morphological data of four populations from two bogs in southern Sweden are presented. From each bog one population of Sphagnum rubellum was sampled from the mire expanse and one population of S. capillifolium from the mire margin. Data from isoenzyme-electrophoresis show that there is agenetic difference corresponding to the two morphological taxa. It is also indicated that they may hybridize. The fact that the taxa seem to be better separated at the continental Aggarps Mosse than at the suboceanic Traneröds Mosse would suggest that hybridization occurs more often in coastal than in inland climates.     

Genetic diversity of Poa annua in western Oregon grass seed crops

The genetic diversity of Poa annua L.populations collected from western Oregon grass-seed fields was surveyed using 18 randomly amplified polymorphic DNA (RAPD) markers. Markers from 1357 individual plants from 47 populations collected at three sampling dates (fall, winter, and spring) for 16 sites were used to measure genetic diversity within and among populations. Site histories varied from low to high herbicide selection pressure, and some sites were subdivided by 3 years of differing post-harvest residue management. Gene diversity statistics, simple frequency of haplotype occurrence, and analysis of molecular variance (AMOVA) revealed the presence of significant variability in P. annua among sites, among collection dates within sites, and within collection dates. Nei gene-diversity statistics and population-differentiation parameters indicated that P. annua populations were highly diverse. Mean Nei gene diversity (h) for all 47 populations was 0.241 and total diversity (H_T) was 0.245. A greater proportion of this diversity, however, was within (H_S=0.209) rather than among (G_ST=0.146) populations. When populations were grouped by season of collection, within-group diversity was H_S=0.241, while among-group diversity was G_ST=0.017. When populations were grouped by site, within-group diversity was H_S=0.224, while among-group diversity was G_ST=0.087. The diversity among populations within season for fall, winter, and spring collections was G_ST=0.121, 0.142, and 0.133, respectively. Populations collected from fields with histories of high herbicide selection pressure showed low differentiation among collection dates, with G_ST as low as 0.016, whereas those collected from fields with low herbicide selection pressure showed greater differentiation among collection dates, with G_ST as high as 0.125. At high selection-pressure sites, populations were also lower in gene diversity (as low as h=0.155), while at low selection-pressure sites there was higher gene diversity (as high as h=0.286). The site to site variability was greater for the high selection-pressure sites (G_ST=0.107 or 69% of the total among-population variance), while the season of germination variability was greater at sites of low herbicide-selection pressure (G_ST=0.067, or 70% of the total among-population variance). High initial diversity coupled with a long-term re-supply of genotypes from the seed bank must have been factors in maintaining the genetic diversity of this weed despite the intensive use of herbicides. Knowledge of the genetic diversity of Willamette Valley P. annua should help in formulating more effective strategies for managing this weed. Received: 24 July 1999 / 11 November 1999     

Reproduction in Myurium hochstetteri

Abstract

Isozyme electrophoresis was used to study the genetic relationship between the morphologically overlapping taxa Sphagnum rubellum and S. capillijolium. Multilocus genotypes were determined for over 1300 plants representing 36 sites in Scandinavia, Great Britain and southern Germany. In total 121 multilocus genotypes were recorded. The 14 most abundant genotypes constituted ca 70% of the shoots analysed. From the genotypic data a species index (SI) was constructed to test the single- and two-species hypotheses. At the molecular level, a division corresponding to the two taxa was evident. S. rubellum was recorded from wet, ombrotrophic to weakly minerotrophic bog/poor fen habitats, while S. capillijolium was usually found in drier, minerotrophic forest/(sub) alpine heath habitats. Few individuals (1.6%) had mixed isozyme marker alleles, and these tended to occur in mixed populations from mire margins. Sphagnum capillijolium was only recorded at one out of eight British sites. Species concepts and methods for integrating genetic data with morphological data are discussed.     

Genetic diversity among geographically separated populations of Nepenthes mirabilis

The distribution of Nepenthes mirabilis ranges from Northeast (NE) to South (S) Thailand. Eleven individuals from NE, S and Suen Jatujak market in Bangkok, Central (C) Thailand, were collected and divided into four populations according to their geographical areas. These four populations were analyzed to determine a genetic diversity profile using thirteen inter-simple sequence repeat markers. The individuals produced 75.18% polymorphic banding profiles. The Shannon’s index was used to estimate genetic diversity. Total genetic diversity (H _T) and inter-population genetic diversity (H _S) were 0.854 and 0.678, respectively. The degree of genetic differentiation (G _ST) of the species populations is 0.206, whereas the gene flow (Nm) among all the various geographical area populations is 1.016. Both the dendrogram and the results of the Shannon’s diversity index suggest great genetic diversity. These results support the broad range of distribution sites of Nepenthes mirabilis, which would require high genetic diversity to adapt to the environmental variations that can be found between NE, C, and S Thailand. ANOVA shows that the genetic diversity in each population is not significantly different (P > 0.05). Mantel tests reveal that geographical distance is an important factor for affecting the genetic distances among populations.     

Population genetic analysis of Elliottiaracemosa (Ericaceae), a rare Georgia shrub

Genetic and genotypic diversity found within populations of threatened plant species can have important implications for their conservation and management. In this study we describe genetic and genotypic diversity found within 10 populations of the endemic shrub Elliottiaracemosa (Ericaceae), the Georgia plume. E. racemosa is a threatened species known from fewer than 50 locations, all within the state of Georgia, USA. Seedset is limited to nonexistent in some E. racemosa populations and sexual recruitment has not been documented. However, the species is known to spread vegetatively via root-sprouts. Twenty-one allozyme loci were resolved for E. racemosa, nine of which were polymorphic. Compared with other woody taxa, E. racemosa has low genetic (i.e. allelic) diversity within populations (H_ep = 0.063) and at the species level (H_es = 0.091). Most of the genetic variation (82%) was found within populations, and genetic identities between populations were high (mean I = 0.96). However, genotypic diversity (i.e. the number of multilocus genotypes) differed markedly among populations. Two of the 10 populations consisted almost entirely of single multilocus genotypes, whereas more than 20 multilocus genotypes (in samples of 48 stems) were detected at three sites. Sites in which few multilocus genotypes were detected have low seedset, suggesting that the lack of clonal diversity limits reproduction in some populations of this reportedly self-incompatible species.     

HIGH LEVELS OF GENETIC VARIABILITY IN THE HAPLOID MOSS PLAGIOMNIUM CILIARE

Horizontal starch-gel electrophoresis was used to measure variability at 14 enzyme loci from 13 natural populations of the dioecious moss Plagiomnium ciliare. Overall levels of genetic polymorphism were unexpectedly high for a haploid organism. Using a 1% frequency criterion, 71% of the loci surveyed were polymorphic for the species as a whole. The number of alleles per polymorphic locus for the species as a whole was 2.82 ± 0.34 (mean ± standard error), and mean gene diversity per locus was 0.078 ± 0.035. While total gene diversity (H_T = 0.178) was similar to that observed for highly outcrossed diploid plants such as pines, the variance within (H_S = 0.098 ± 0.027) and among (D_ST = 0.080 ± 0.033) populations was more evenly distributed than that reported for populations of conifers. Genetic distances between populations ranged from 0.0002 to 0.2064, with mosses from the Piedmont region of the southeastern United States showing less differentiation among populations than did mosses from the Appalachian Mountains. Gene diversity was much reduced in populations from disturbed, secondary forests in the Piedmont (0.058 ± 0.018) relative to those from minimally disturbed, primary forests in the mountains (0.146 ± 0.048). Intensive sampling within populations revealed heterogeneity even within small (5 × 5 cm) clumps. The discovery of high levels of genetic variability in a plant with a dominant haploid life cycle challenges the traditional view of bryophytes as a genetically depauperate group. Multipleniche selection is proposed as a possible explanation for this anomaly, but the data are also consistent with the view that allozyme polymorphisms are selectively neutral.     

Genetic diversity and gene flow estimates among three populations of Botryodiplodia theobromae causing die-back and bark canker of pear in Punjab

Three populations of Botryodiplodia theobromae causing die-back and bark canker of pear in Punjab were analysed to know about the genetic diversity, gene flow, heterogeneity and the probable rate of spread of races capable of overcoming the resistance present in elite cultivars. There was no relationship between the morphologically similar isolates and their pathogenic behaviour. Majority of the isolates of B. theobromae within and among the populations produced lesions of 1.9–7.2 × 0.8–3.1 cm size on detached pear twigs cv. Punjab Beauty. Incubation period and per cent infection also varied within and among the three populations of the pathogen. The genetic diversity was calculated on the basis of allele frequencies of nine simple sequence repeat (SSR) markers using Nei's genetic diversity formulae. Allele frequencies (X_ij ) varied significantly among the three populations ranging from 0.0 to 1.0. The mean genetic diversities within population (H _S) also varied in all the locations ranging from 0.18 to 0.36 indicating a high genetic diversity within the population. The total genetic diversity across all the populations (H _T) ranged between 0.1 and 0.5 with a mean of 0.36, and differed significantly from the mean H _S (0.25). Diversity indices of SSR loci varied from low (H _S < 0.1) to high (H _S > 0.4) across all the populations (G _ST) of B. theobromae in Punjab which were consistent over the presumed SSR loci with a mean G _ST of 0.29. The lower G _ST values of 0.13, 0.10, 0.11 and 0.13 were observed at LAS15-16, LAS27-28, BOT17-18 and BOT35-36 loci, respectively, showing high genetic diversity among all the isolates. However, at BOT19-20 locus, the G _ST value observed was 0.72 thereby indicating low diversity in the population at this locus. Out of 25 loci, 8 loci showed the gene flow (Nm) < 1 indicating a high genetic differentiation within the population and the remaining 6 loci showed the Nm > 1 indicating the frequent existence of gene flow across the populations of B. theobromae. Pairwise comparison (G _ST) values among all the loci were ranging from 0.18 to 0.19, which indicate a low genetic differentiation among the populations of B. theobromae. The high genetic diversity (H _S) within the population was observed in the present study suggesting that B. theobromae possess high variability in Punjab. Keeping this in view, new races would be expected soon outside the state of origin, as naturally occurring gene flow is likely to be increased by the human activity for comprehensive cultivation of pear in the near future. Therefore, it is difficult to predict the durability of resistant sources in Punjab, which in turn emphasises the identification and introgression of R genes into commercial cultivars.     

四川甘孜州高山葡萄酒产区酵母菌多样性分析

【背景】西南高山葡萄酒产区的甘孜州产区,具有生产优质葡萄酒的自然禀赋。【目的】研究四川甘孜州葡萄酒产区真核微生物种类多样性、本土酿酒酵母遗传多样性,以及商业酵母对本土酵母多样性的影响。【方法】利用ITS高通量测序技术对赤霞珠接种发酵和自然发酵过程中的微生物进行多样性分析,并利用Interdelta指纹图谱分析法,对经过26S rRNA基因鉴定的野生酿酒酵母基因型进行分类。【结果】ITS测序结果显示,接种发酵和自然发酵各时期均注释到7个科7个属的酵母,通过Interdelta指纹图谱分析发现甘孜州产区的酿酒酵母共有5种基因型。该产区酿酒酵母的6株代表菌株与我国其他产区109株酿酒酵母的进化树分析结果显示,均与来自北京产区的酿酒酵母菌株亲缘关系更近。【结论】甘孜州葡萄酒子产区酵母资源丰富,表现出较高的微生物多样性和中等程度的本土酿酒酵母基因型多样性,为后续优良本土酵母菌株的筛选奠定基础。     

Genetic diversity of the endangered Chinese endemic herb Primulina tabacum (Gesneriaceae) revealed by amplified fragment length polymorphism (AFLP)

Primulina tabacum Hance, is a critically endangered perennial endemic to limestone area in South China. Genetic variability within and among four extant populations of this species was assessed using AFLP markers. We expected a low genetic diversity level of this narrowly distributed species, but our results revealed that a high level of genetic diversity remains, both at population level (55.5% of markers polymorphic, H _E = 0.220, I _S = 0.321), and at species level (P = 85.6% of markers polymorphic, H _E = 0.339, I _S = 0.495), probably resulting from its refugial history and/or breeding system. High levels of genetic differentiation among populations was apparent based on Nei’s genetic diversity analysis (G _st=0.350). The restricted gene flow between populations is a potential reason for the high genetic differentiation. The population genetic diversity of P. tabacum revealed here has clear implications for conservation and management. To maintain present levels of genetic diversity, in situ conservation of all populations is necessary.     

Genetic variation in the liverwort Bazzania trilobata inferred from ISSR markers

Abstract

The distribution of Bazzania trilobata in Poland coincides with two parts of the natural distribution range of Norway spruce: the mountains of southern Poland and the northeastern lowlands. The occurrence of this species is connected with primeval forest communities and it was recognized as a relict of them. Genetic variation of 10 populations of B. trilobata from two different regions of Poland (lowlands and mountains) was studied in order to establish the genetic structure of this species and to compare the level of genetic variation within and among populations originating from primeval and managed forests. An analysis based on polymorphic inter-simple sequence repeat (ISSR) loci revealed a high level of total gene diversity in B. trilobata (H _T=0.308). A higher amount of polymorphism was found among than within populations. Genetic variation of populations from the primary forest (Tatras and Bia?owieza National Park) was higher than for those originating from disturbed habitats. The Bayesian method showed consistent grouping of samples corresponding with populations, with the best grouping in 12 different clusters reflecting a geographic pattern. The geographic pattern of genetic differentiation was supported by a neighbour-joining (NJ) dendrogram based on genetic distances. All mountain populations were grouped together in one subcluster, but lowland populations were more differentiated and did not form one clear group.     

Levels of allozyme diversity in closely related toadflaxes (<Emphasis Type="Italic">Linaria</Emphasis>, Plantaginaceae) and their correspondence with the breeding systems of the species

Toadflaxes (Linaria Miller) represent the largest genus of the tribe Antirrhineae (formerly included in the Scrophulariaceae) of the Plantaginaceae family. These taxa vary according to their ranges (narrow-regional–widespread), biological traits (duration, flower morphology, breeding system) and ecological preferences. No comparative genetic studies have been performed up to the moment and the levels and distribution of genetic diversity within this genus remain undocumented. We have conducted an allozyme study in 8 taxa of Section Supinae. Five of them are narrow endemic, self-incompatible, insect-pollinated outcrossers that inhabit relatively unaltered habitats. The other three taxa are widespread, small-flowered selfers that inhabit crops subjected to high levels of recurrent disturbance. Linaria taxa showed moderate to high levels of genetic diversity. Parameters of genetic diversity were directly addressed to differences in breeding systems. Mean number of alleles per locus, total genetic diversity and genetic diversity within populations were higher among the outcrossers than among the selfers, (A _e = 2.28 vs. 1.23; H _T = 0.24 vs. 0.13; H _S = 93.99% vs. 54.2%) while genetic diversity among populations and population differentiation were lower for the outcrossers than for the selfers (D _ST = 0.02% vs. 45.98%; G _ST = 0.03 vs. 0.52). Gene flow within and among populations produced a higher number of different genotypes (mean N _G = 16 for outcrossers vs. 5.4 for selfers) and migrants (mean N _m = 4.58 for outcrossers vs. 0.84 for selfers) that were attributed to an effective pollinator service in outcrossing populations. Differences in the levels and distribution of the genetic diversity are discussed in relation to biological and autoecological constraints of each group of taxa.     

北沙柳群体遗传多样性和遗传结构分析

以内蒙古北沙柳(Salix psammophila)国家种质资源库内9个群体(P1~P9)288个无性系为实验材料,利用TP-M13-SSR技术,选取22对具有多态性EST-SSR北沙柳引物,采用毛细管电泳对PCR产物进行检测,分析北沙柳遗传多样性、分化程度和群体遗传结构,为北沙柳种质资源库遗传管理、无性系鉴定、品种选育、遗传改良和构建指纹图谱提供理论依据。结果显示:(1)22对EST-SSR引物共检测到222个等位基因,各位点平均等位基因数(A)为10,四倍体基因型丰富度(G)和特异基因型(G1)总和分别为1 460和802个,平均特异基因型比率(P1)和种质鉴别率(P2)分别为45.86%和13.21%。(2)9个群体平均等位基因数(A)为7.475,基因型丰富度(G)为15.586,观察杂合度(Ho)和期望杂合度(He)分别为0.577和0.638。以期望杂合度He为标准,北沙柳群体遗传多样性水平最低的是P1和P9。(3)北沙柳群体遗传分化系数仅为0.02,AMOVA分子变异分析显示,北沙柳群体大部分遗传变异来自群体内(97%),群体间变异仅为3%。(4)三维主成分、聚类和Structure群体遗传结构分析显示,9个群体被划分为2个组,Mantel检验表明北沙柳遗传距离与地理距离极显著相关(r=0.684 P0.001)。研究表明,北沙柳种质资源具有丰富的遗传多样性,这是其具有耐旱、耐寒、耐高温、耐沙埋和抗风蚀等适应性较强的分子基础;北沙柳的遗传变异集中在群体内;分布区群体呈现由中心向边缘群体扩张分化的趋势。     

Genetic diversity and fitness in Scabiosa columbaria in the Swiss Jura in relation to population size

Due to changes in land use, remnants ofunfertilised, nutrient-poor calcareousgrassland in the Swiss Jura are small in areaand are highly fragmented. We selected 89 seedfamilies from eleven populations of varioussizes of Scabiosa columbaria for a studyof molecular diversity, and used the samematerial in a greenhouse experiment to measurevariation in fitness-related traits and theability of populations to cope withcompetition. Using RAPD-PCR we detected 71RAPD-phenotypes among 87 genotypes. Moleculardiversity within populations was variable andrelatively high, with an expectedheterozygosity H _e ranging from 0.09 to0.24. H _e, the Shannon index (SI) and thepercentage of polymorphic bands were notcorrelated with population size, but thesmallest populations had the lowest moleculardiversity (H _e, SI). Populationdifferentiation was moderate with 12% of themolecular diversity among populations. Measuresof fitness in the greenhouse differed amongseed families (P < 0.001), but not amongpopulations. Mean above-ground biomass waslargely reduced when plants had to compete withBromus. Mean fitness of populationsdecreased when molecular diversity (H _e)was low, but only when plants had to competewith Bromus (P = 0.02). Accordingly, therelative competition ability of Scabiosaplants decreased when molecular diversity(H _e) was low (P = 0.01). Our resultssuggest an increased risk of local extinctionof Scabiosa columbaria in the Swiss Juracaused by a decreased viability and reducedphenotypic plasticity due to genetic erosion insmall populations.     

Allozyme diversity and genetic structure of marginal and central populations of Corylus avellana L. (Betulaceae) in Europe

Corylus avellana L. (hazel, Betulaceae) is a long-lived, widespread shrub in Europe, having its northern range margin in Fennoscandia and a postglacial history involving range-expansion from refugial areas in southern Europe. In this study, we tested for a relationship between marginality and low within-population genetic diversity by assessing patterns of variation at 14 putatively neutral allozyme loci (comprising 43 putative alleles) within and between 40 natural populations of C. avellana along a north-south transect in Europe. Geographically marginal populations (central Sweden) showed lower levels of within-population diversity than populations in more central regions, as indicated by significant negative correlations between latitude and the percentage of polymorphic loci (r_S=–0.47, P < 0.001), the average number of alleles per locus (r_S=–0.65, P < 0.001), the expected heterozygosity (r_S=–0.19, P < 0.05), and the proportion of distinguishable genotypes (r_S=–0.56, P < 0.001). These patterns, combined with the unusually high between-population component of gene diversity (G_ST=19.7%) and allelic richness (A_ST=24%) in the marginal region, can be attributed to historical bottlenecks during the species postglacial range-expansion, but may also reflect a history of genetic drift in the small, isolated populations occupying the marginal region. Information on the spatial distribution of genotypes provide further support for a role of vegetative reproduction (layering) in the structuring of genetic variation within populations.     

Population genetic structure of Ceriops tagal (Rhizophoraceae) in Thailand and China

Knowledge of the amount and patterns of genetic variation within and among populations of mangrove trees is essential for devising optimum genetic management strategies for their conservation and sustainable utilization. Ceriops tagal is a widespread viviparous mangrove. Genetic diversity in the species was examined with inter-simple sequence repeat (ISSR). Nine natural populations were collected from Thailand and China. The estimates of genetic variation were extremely low (H_T = 0.0179 ± 0.005, H_S = 0.0084 ± 0.001), and only 47% of the total gene diversity was maintained within populations (G_ST = 0.529). The eastern coastal populations of Thailand were more similar to populations from China than to populations from the western coastline of Thailand. A high level of Nei's genetic identity exists between populations of C. tagal (I = 0.989), suggesting their common ancestry. The low levels of genetic diversity in the species may result from a series of genetic bottlenecks during several glacial epochs.     

The population genetic diversity and pattern of Pteroceltis tatarinowii,a relic tree endemic to China,inferred from SSR markers

Pteroceltis tatarinowii (Cannabaceae), a relic tree endemic to China, is mainly distributed in limestone mountains and has a wide geographical range. In this study, 12 microsatellite primer pairs were assayed to analyse the genetic pattern and gene flow among 461 individuals sampled from 23 wild populations of P. tatarinowii. A high level of genetic diversity was detected based on high values of total alleles (159), the number of alleles (N_A = 6.373), expected heterozygosity (H_E = 0.696) and observed heterozygosity (H_O = 0.679). The high genetic diversity in this species may be attributed to its long‐life history, wide geographical distribution and wind dispersal. Only low genetic differentiation (G_ST = 0.137, F_ST = 0.138) was found among populations. Gene flow (migrants per generation, N_m) was estimated to be 1.56. This moderate level of gene flow possibly decrease interpopulation differentiation by buffering against genetic drift and improving gene exchange. However, spatial genetic structure was detected throughou the sampled range of the species (r = 0.311, p < 0.05) as well as in southern China (r = 0.453, p < 0.05), and may be related to terrain heterogeneity and the demographic history of P. tatarinowii. The east‐west high mountains of southern China might serve as physical barriers to seed and pollen flow. The isolation and local adaptation of different refugia may further limit gene flow. In addition, geographically remote populations might fail to effectively disperse pollen and seeds. Based on the above‐mentioned results, some suggestions for the conservation of the species are presented.     

Genetic structure of two endangered pitcher plants,Sarracenia jonesii and Sarracenia oreophila (sarraceniaceae)

Sarracenia jonesii and S. oreophila arc insectivorous perennial plants of the southeastern United States. Both pitcher plant taxa arc rare and endangered. Allozyme diversity was assessed for eight of the ten extant populations of S. jonesii and 14 of the 35 remaining S. oreophila populations. Genetic diversity was low and comparable for both species (H_es = 0.086 and 0.082 for S. jonesii and S. oreophila, respectively). Mean population genic diversity (H_ep) was 0.061 for S. jonesii and 0.060 for S. oreophila. Estimates of genetic diversity were typical of those commonly associated with endemic species. Small populations of each species and geographically disjunct populations tended to maintain less genetic diversity. Indirect estimates of gene flow were comparable for S. oreophila (Nm = 1.62) and S. jonesii (Nm = 1.07).     

Genetic Variation within Native Populations of Endemic Silkmoth Antheraea assamensis (Helfer) from Northeast India Indicates Need for In Situ Conservation

A. assamensis is a phytophagous Lepidoptera from Northeast India reared on host trees of Lauraceae family for its characteristic cocoon silk. Source of these cocoons are domesticated farm stocks that crash frequently and/or wild insect populations that provide new cultures. The need to reduce dependence on wild populations for cocoons necessitates assessment of genetic diversity in cultivated and wild populations. Molecular markers based on PCR of Inter-simple sequence repeats (ISSR) and simple sequence repeats (SSR) were used with four populations of wild insects and eleven populations of cultivated insects. Wild populations had high genetic diversity estimates (H_i = 0.25; H_S = 0.28; H_E = 0.42) and at least one population contained private alleles. Both marker systems indicated that genetic variability within populations examined was significantly high. Among cultivated populations, insects of the Upper Assam region (H_i = 0.19; H_S = 0.18; H_E = 0) were genetically distinct (F _ST = 0.38 with both marker systems) from insects of Lower Assam (H_i = 0.24; H_S = 0.25; H_E = 0.3). Sequencing of polymorphic amplicons suggested transposition as a mechanism for maintaining genomic diversity. Implications for conservation of native populations in the wild and preserving in-farm diversity are discussed.