The Underlying Structure of Adaptation under Strong Selection in 12 Experimental Yeast Populations

The aims of this study were to determine (i) whether adaptation under strong selection occurred through mutations in a narrow target of one or a few nucleotide sites or a broad target of numerous sites and (ii) whether the programs of adaptation previously observed from three experimental populations were unique or shared among populations that underwent parallel evolution. We used archived population samples from a previous study, representing 500 generations of experimental evolution in 12 populations under strong selection, 6 populations in a high-salt environment and 6 populations in a low-glucose environment. Each set of six populations included four with sexual reproduction and two with exclusively asexual reproduction. Populations were sampled as resequenced genomes of 115 individuals and as bulk samples from which frequencies of mutant alleles were estimated. In a high-salt environment, a broad target of 11 mutations within the proton exporter, PMA1, was observed among the six populations, in addition to expansions of the ENA gene cluster. This pattern was shared among populations that underwent parallel evolution. In a low-glucose environment, two programs of adaptation were observed. The originally observed pattern of mutation in MDS3/MKT1 in population M8 was a narrow target of a single nucleotide, unique to this population. Among the other five populations, the three mutations were shared in a broad target, sensing/signaling genes RAS1 and RAS2. RAS1/RAS2 mutations were not observed in the high-salt populations; PMA1 mutations were observed only in a high-salt environment.     

Genic Heterozygosity and Protein Polymorphism among Local Populations of OENOTHERA BIENNIS

Twenty enzyme loci were studied in 44 Illinois populations of Oenothera biennis; four were polymorphic. Most of the variation was distributed between populations. Fifty-nine percent of the populations had one genotype, 27% two genotypes and the remaining 16% from three to five genotypes; the average was 1.50. The proportion of genetic diversity present in single populations is.38 of that present in the state. Members of single populations were uniformly heterozygous for 1 to 4 loci. The mean heterozygosity per population ranged from 0 to 20%. For Illinois populations collectively, heterozygosity averaged 4.5%. There was much gene frequency heterogeneity between populations. The true standardized genetic variance among populations for alleles at polymorphic loci varied from.40 to.78. Populations from Cook County were much more similar inter se than those downstate, had fewer genotypes and polymorphic loci, and had less heterozygosity than downstate populations. The mean normalized genetic identity among Cook County populations was.987 versus.947 for downstate populations. The mean number of genotypes per population in Cook County was 1.06 versus 2.40 in downstate populations. There was only one polymorphic locus in Cook County, VLP. The genetic structure of Oe. biennis suggests that single populations are colonized by one, or at best a few individuals. Cook County populations are judged to be less variable than downstate populations because the mean age of the populations probably is less than that of those downstate.     

Morphometric variation in nearly unstudied populations of the most studied mammal: The non-commensal house mouse (Mus musculus domesticus) in the Near East and Northern Africa

The phenotypic consequences in the house mouse (Mus musculus domesticus) of the transition from an ordinary field-dwelling rodent to a species that is dependent on human populations was studied by investigating the morphometric variation of non-commensal populations of M. m. domesticus from Syria, Jordan, SW Iran, and Libya and comparing them with that of conspecific commensal populations from Eastern Turkey, Greece, and Bulgaria. Commensal populations of M. musculus musculus from the Czech Republic were used as an outgroup. About 849 adult specimens of M. musculus were analysed by multivariate procedures based on standard molar, skull and body measurements. As expected, there was considerable variation among the studied populations and a good correspondence between morphometric and geographic distances. The resulting morphometric tree was consistent with the hypothesis that the original radiation of M. m. domesticus took place somewhere in the Near East. Commensal populations of M. m. domesticus form a single derived branch. Specimens originating from four different sites in eastern Syria showed the greatest similarity to one another and possessed relatively bigger molars than the other studied populations. Commensal populations were characterised by longer tails when compared to non-commensal populations, which suggests an adaptation for living in a more three-dimensionally heterogeneous environment for commensal populations.     

Genetic diversity of cultured populations of giant freshwater prawn (Macrobrachium rosenbergii) in China using mtDNA COI and 16S rDNA markers

Partial sequences of mitochondrial DNA 16S rDNA and COI genes (395 bp and 498 bp respectively) were sequenced from samples of ten cultured populations of Macrobrachium rosenbergii (Giant Freshwater Prawn – GFP) in Zhejiang, Guangdong and Guangxi Provinces in China and two wild populations of GFP from Mekong River and Dongnai River in Viet Nam. Five haplotypes of 16S rDNA were identified in the 360 samples. The wild populations displayed nucleotide diversity (π) of 0.0008 and 0.0003, and genetic diversity (h) of 0.3030 and 0.1310 in the Mekong River and Dongnai River respectively. The cultured populations displayed no significant genetic diversity. COI sequences identified 17 haplotypes based on 21 polymorphic sites. At this marker, the 12 populations showed a range of h from 0.1290 to 0.6940 and π from 0.0003 to 0.0073. The largest genetic distance (Da) among the 12 populations was 0.0065 (between ZJB and BT/DN populations) and the lowest Da was 0.0003 (between GDD and GDA populations). The wild populations had higher genetic diversity than the cultured populations, but three of cultured populations from Zhejiang (ZJA, ZJB and ZJC) had π higher than wild populations, because they originated from Thailand, Bangladesh and the Mekong River in Viet Nam.     

Genetic diversity within and among the wild populations of Murraya koenigii (L.) Spreng., as revealed by ISSR analysis

Murraya koenigii (L.) Spreng., commonly known as curry leaf plant, is found in the different hilly regions of India. In the present study, fifty-nine accessions representing eight wild populations of M. koenigii were analyzed using thirteen ISSR primers. A total of 152 bands were amplified, out of which, 136 were polymorphic corresponding to 89.47% polymorphism across the accessions. The pairwise population genetic distances were calculated for all the populations that varied from 0.05 to 0.13 between the populations of M. koenigii. AMOVA and Nei’s genetic diversity analysis revealed higher genetic variations within populations than among the populations. The clustering of populations in the dendrogram was not in congruence with geographical affiliations. The results indicate that the ISSR method is sufficiently informative and powerful to estimate the genetic diversity in M. koenigii populations. As M. koenigii is an important wild plant genetic resource, therefore, information on genetic variability might be a potential source as breeding material for development of commercially valuable traits in M. koenigii plants.     

Distribution of genetic variability in southern populations of Scots pine (Pinus sylvestris L.) from the Alps to the Apennines

Alpine and Northern Apennine populations of Pinus sylvestris collected from eight different Italian sites were analyzed by mitochondrial nadI intron and InterSimple Sequence Repeat (ISSR) markers, in order to describe the natural level of genetic variability and to clarify their genetic relationships. The small Northern Apennine populations are the southernmost populations of this conifer in Italy. All the analyzed populations were spontaneous and reforested areas were excluded. The analysis of the polymorphisms in the nad 1 intron sequence confirmed that the Italian P. sylvestris populations have the same mitotype (mitotype a) as the Central European ones. In the genomic ISSR analysis the proportion of shared alleles between the individuals showed the highest degree of differentiation between French and Italian populations and a divergence between the Alpine and Apennine populations. Alpine populations showed a higher genetic variability (GD 0.310±0.0252) than Apennine samples (GD 0.217±0.019). In addition, the individuals from the Apennines did not show a clear population structure, suggesting a common genetic constitution of Apennine P. sylvestris. It is likely that this constitution is the result of a progressive genetic isolation between the Alpine and the Northern Apennine populations from the early Holocene. The genetic constitution of the Northern Apennine populations suggests the opportunity of a management where in situ conservation of such small populations could be coupled to their use as sources of suitable local reforesting materials.     

Genetic Divergence and Signatures of Natural Selection in Marginal Populations of a Keystone,Long-Lived Conifer,Eastern White Pine (Pinus strobus) from Northern Ontario

Marginal populations are expected to provide the frontiers for adaptation, evolution and range shifts of plant species under the anticipated climate change conditions. Marginal populations are predicted to show genetic divergence from central populations due to their isolation, and divergent natural selection and genetic drift operating therein. Marginal populations are also expected to have lower genetic diversity and effective population size (N _e) and higher genetic differentiation than central populations. We tested these hypotheses using eastern white pine (Pinus strobus) as a model for keystone, long-lived widely-distributed plants. All 614 eastern white pine trees, in a complete census of two populations each of marginal old-growth, central old-growth, and central second-growth, were genotyped at 11 microsatellite loci. The central populations had significantly higher allelic and genotypic diversity, latent genetic potential (LGP) and N _e than the marginal populations. However, heterozygosity and fixation index were similar between them. The marginal populations were genetically diverged from the central populations. Model testing suggested predominant north to south gene flow in the study area with curtailed gene flow to northern marginal populations. Signatures of natural selection were detected at three loci in the marginal populations; two showing divergent selection with directional change in allele frequencies, and one balancing selection. Contrary to the general belief, no significant differences were observed in genetic diversity, differentiation, LGP, and N _e between old-growth and second-growth populations. Our study provides information on the dynamics of migration, genetic drift and selection in central versus marginal populations of a keystone long-lived plant species and has broad evolutionary, conservation and adaptation significance.     

Esterase Allozymes of Soybean Cyst Nematode,Heterodera glycines,from China,Japan, and the United States

Individual females from 19 populations of Heterodera glycines from China, Japan, and the United States were analyzed for esterase allozyme polymorphism. Eight esterase electrophoretic phenotypes were resolved. Four putative loci, est-1, est-2, est-3, and est-4, were identified, having one, one, two, and one allele, respectively. The four loci expressed six genotypes in the four Chinese populations. Loci est-2, est-3, and est-4 were identified in five Japanese populations and expressed five genotypes, whereas only loci est-2 and est-3 were identified in 10 populations from the United States and expressed four genotypes. Putative alleles at each locus were defined as characters for data analysis. Phylogenetic analysis using parsimony (PAUP) was utilized to determine relationships among the 19 populations. More loci and alleles in populations from China and phylogenetic similarities among populations from Japan and the United States are consistent with a founder effect resulting from dissemination of progenitor H. glycines from China to Japan and subsequent introductions of founder populations from Japan to the United States.     

Genetic Diversity and Population Structure of the Rare and Endangered Plant Species Pulsatilla patens (L.) Mill in East Central Europe

Pulsatilla patens s.s. is a one of the most endangered plant species in Europe. The present range of this species in Europe is highly fragmented and the size of the populations has been dramatically reduced in the past 50 years. The rapid disappearance of P. patens localities in Europe has prompted the European Commission to initiate active protection of this critically endangered species. The aim of this study was to estimate the degree and distribution of genetic diversity within European populations of this endangered species. We screened 29 populations of P. patens using a set of six microsatellite primers. The results of our study indicate that the analyzed populations are characterized by low levels of genetic diversity (H_o = 0.005) and very high levels of inbreeding (F_IS = 0.90). These results suggest that genetic erosion could be partially responsible for the lower fitness in smaller populations of this species. Private allelic richness was very low, being as low as 0.00 for most populations. Average genetic diversity over loci and mean number of alleles in P. patens populations were significantly correlated with population size, suggesting severe genetic drift. The results of AMOVA point to higher levels of variation within populations than between populations.The results of Structure and PCoA analyses suggest that the genetic structure of the studied P. patens populations fall into three clusters corresponding to geographical regions. The most isolated populations (mostly from Romania) formed a separate group with a homogeneous gene pool located at the southern, steppic part of the distribution range. Baltic, mostly Polish, populations fall into two genetic groups which were not fully compatible with their geographic distribution.Our results indicate the serious genetic depauperation of P. patens in the western part of its range, even hinting at an ongoing extinction vortex. Therefore, special conservation attention is required to maintain the populations of this highly endangered species of European Community interest.     

Suppressor Systems of Segregation Distorter (SD) Chromosomes in Natural Populations of DROSOPHILA MELANOGASTER

Several natural populations of D. melanogaster were investigated for the presence (or absence) of the Segregation Distorter ( SD) chromosomes and their suppressor systems. The SD chromosomes were found, at frequencies of a few percent, in two independent samples taken in different years from a Raleigh, North Carolina, population, whereas no SD chromosomes were found in samples collected from several populations in Texas. The populations in these localities were found to contain suppressor X chromosomes in high frequencies (75% or higher). They also contained relatively low frequencies of partial suppressor or insensitive second chromosomes of varying degrees, but completely insensitive second chromosomes were practically absent in all populations examined. The frequencies of suppressor X chromosomes, as well as those of the partially insensitive or suppressor second chromosomes, were the same among the populations investigated. This suggests the possibility that the development of a suppressor system of SD in a population could be independent of the presence of an SD chromosome. Segregation distortion appeared to be occurring in natural genetic backgrounds, but the degree of distortion varied among males of different genotypes. There were many instances in which the SD chromosomes showed transmission frequencies from their heterozygous male parents that were smaller than 0.6 and, in several cases, even smaller than 0.5. The presence of a recessive suppressor, or suppressors, of SD in natural populations was suggested.     

The development of radioresistance in irradiated drosophila nebulosa populations

The adaptive value of experimental populations of Drosophila nebulosa, irradiated each generation with doses of 500, 1000 and 2000 R of Co-60 gamma-rays, was measured with respect to their ability to compete with non-irradiated Drosophila willistoni. Two groups of experiments were developed: (a) to investigate the effects of repeated irradiation each generation on D. nebulosa under interspecific competition; (b) to demonstrate the radioresistance of D. nebulosa populations with different histories of irradiation. The results obtained through the interspecific competition were confirmed by tests of egg-laying capacity, hatchability and productivity of D. nebulosa from the competing populations. The populations with previous histories of gamma-irradiation were shown to be less susceptible than control populations to the detrimental effects of a new exposure to irradiation. This suggests that radioresistance developed in the D. nebulosa populations that had been irradiated over several generations.     

菲律宾蛤仔EST-SSRs标记开发及不同地理群体遗传多样性

利用13对微卫星引物对大连、莆田、青岛3个地理群体蛤仔遗传多样性进行了检测。结果表明:13个基因座共检测到154个等位基因,每个座位检测到的等位基因数在2-7个之间,平均有效等位基因数为2.7657;3个群体平均观测杂合度分别为0.4387、0.4194、0.2383,平均期望杂合度分别为0.6488、0.6484、0.5526;群体间的遗传多样性差异不显著(P＞0.05)。NJ聚类结果显示大连和莆田群体的蛤仔亲缘关系较近,二者与青岛群体关系较远。3个群体均有不同程度的偏离Hardy-Weinberg平衡现象,表明各群体基因频率和基因型频率的稳定性相对较低。本研究所获得的微卫星标记的多态信息含量(PIC)>0.5,说明这些微卫星位点的多样性较高,可为下一步遗传图谱构建研究提供参考。     

Evidence for multiple, autoploid origins of agamospermous populations in Eupatorium sessilifolium (Asteraceae)

Comparative analyses were made of agamospermous populations of Eupatorium sessilifolium, which have previously been documented to be polyploid, to determine whether they are alloploid or autoploid in origin and to assess the possibility that they have arisen more than once. There was no variability in ITS sequences among seven agamospermous and eight sexual diploid populations of E. sessilifolium, which is consistent with morphological observations in suggesting that the agamospermous populations were autoploids. The ITS sequence characteristic of E. sessilifolium differs from all other North American species by a minimum of 15 changes, and heterogeneity or polymorphism would be expected if the agamospermous populations were alloploids. Analysis of the chloroplast-based trnC-psbM spacer region showed variability among both sexual diploid and agamospermous populations of E. sessilifolium, which suggested that the agamospermous populations stem from multiple origins. Analysis of ISSR data revealed considerable intraspecific variability within E. sessilifolium, and the distribution of variability, with agamospermous populations showing variability from one another, added further evidence for multiple origins of agamospermous populations. The results in conjunction with distributional evidence that the sexual diploid populations of E. sessilifolium are geographically restricted and uncommon suggest that monitoring of populations might be warranted to evaluate whether measures are needed to enhance their continued survival.     

西藏牦牛mtDNA D-loop区的遗传多样性及其遗传分化

通过测定和分析西藏11个牦牛类群114个个体的mtDNA D-loop区全序列,对西藏牦牛的遗传多样性、类群间的亲缘关系及其遗传分化进行了研究。结果表明:①西藏牦牛mtDNA D-loop区全序列长度为890—896 bp,4种核苷酸T、C、A、G的平均比例分别为28.5%、25.3%、32.4%、13.8%,西藏牦牛mtDNA D-loop区富含碱基A+T,表现出一定的碱基偏好性。②共检测到130个变异位点,占分析总位点数的14.33%;其中单一多态位点85个,占多态位点总数的65.38%,简约信息位点45个,占多态位点总数的34.62%。序列变异中碱基缺失、插入和碱基替换等均有,其中碱基替换变异类型中转换114次,颠换12次,在转换变异类型中以A/G、T/C为主,占95.61%,在颠换变异类型中以A/T为主,占75%。③在114个个体中鉴定出90种单倍型,单倍型多样性为0.981±0.008,核苷酸多样性为0.01056±0.00701,均说明西藏牦牛具有丰富的单倍型类型。④90种单倍型分为2个聚类簇(Ⅰ、Ⅱ),聚类簇Ⅰ包含80种单倍型,占全部单倍型的88.89%,涵盖本研究中所有的西藏牦牛类群;聚类簇Ⅱ中有10种单倍型,占单倍型总数的11.11%,涉及的类群有工布江达、帕里、丁青、巴青、江达、类乌齐、桑桑、桑日、斯布,说明西藏牦牛可能有2个母系起源。⑤西藏牦牛类群间核苷酸分歧度(Dxy)在0.503%—1.416%之间,聚类分析和AMOVA分析显示西藏牦牛可分为两大类,康布牦牛、嘉黎牦牛为一类,其余的牦牛类群为另一类。     

Variations in Host Preference among and within Populations of Heterodera trifolii and Related Species

Seven populations of Heterodera trifolii from Arkansas, Kentucky, Pennsylvania, and Australia plus 3 or 4 single-cyst isolates (SCI) from each population were tested for reproduction on seven species of plants to compare the host preferences among and within populations. Common lespedeza, Kummerowia striata cv. Kobe, was a good host for all populations and isolates. Therefore, a plant was considered to be a host if the number of females produced on it was 10% or more of the number on Kobe. All seven populations reproduced on Trifolium repens and T. pratense. None reproduced on Beta vulgaris or Glycine max. One single-cyst isolate from the Australian population produced a few females on T. pratense. The Australian population maintained on carnation, Dianthus caryophyllus, produced females on carnation but not on curly dock, Rumex crispus. However, its subpopulation maintained on T. repens produced females on R. crispus but not on carnation. Four of the other six populations produced females on R. crispus, and four produced females on carnation. Differences in host range were observed among seven of the mother populations and their SCI, and among isolates within each population. Five host range patterns were found in populations and SCI of H. trifolii. Significant quantitative differences occurred among populations in the numbers of females on most hosts, between isolates and their original populations, and among isolates from the same population. SCI selected from white clover produced fewer females on a series of test hosts and had host ranges the same as or narrower than those of the original populations. However, SCI selected from Kobe lespedeza had more females on some hosts and had host ranges the same as or wider than those of the original populations. The host ranges of all populations and SCI of H. trifolii were different from those of populations and SCI of race 3 of H. glycines and H. lespedezae.     

Molecular insights into the genetic and haplotype diversity among four populations of Catla catla from Madhya Pradesh revealed through mtDNA cyto b gene sequences

In the present investigation, the genetic structure of four populations of Catla catla, sequences of mitochondrial gene, cytochrome b (cyto b) from four populations were sequenced and analyzed. The sequences of mitochondrial regions revealed high haplotype diversity and low nucleotide diversity. The lowest 249 polymorphic sites and 0.00 parsimony informative sites were detected in populations of Fish Federation Pond (CCFFB) whereas highest 330 polymorphic sites and 56 parsimony informative sites were detected in populations of Narmada River (CCNRH) in the cyto b gene sequences in Catla catla populations. The twelve different haplotypes were detected among the four populations studied, lowest population specific haplotype as 2.00 was observed in Fish Federation Pond (CCFFB) and highest was in Population of Narmada River and Tighra reservoir. Sequencing of cyto b gene revealed 12 number of haplotypes (h) with haplotype (gene) diversity (Hd) 0.8736 and nucleotide diversity (π) 0.6474. These data clearly indicated that, feral/wild population showing highest values of polymorphisms, parsimony, haplotype diversity showing good, healthy habitat is lotic water (Narmada River) and lentic water body (Tighra reservoir). The results also concluded that the partial cyto b is polymorphic and can be a potential marker to determine ecological habitat based genetic differentiation among the populations.     

P-M phenotypes and their correlation with longitude in natural populations of Drosophila melanogaster from Turkey

We analyzed the P-M gonadal dysgenesis characteristics and the molecular patterns of P and KP elements of 35 populations from distinct locations of Turkey and Cyprus to find out P element dynamics in natural populations of Drosophila melanogaster. The results of Gonadal dysgenesis (GD) tests showed a predominat M?? phenotype for this region. Besides Q populations were also found in less numbers. It was also noticed that there is a strong tendency for the presence of a Q type ??buffer zone?? in the Western part of Turkey. The variation in GD percentage (as a index for P element activity and susceptibility) observed among the populations did not show any clear relationship with some geoclimatic variables, but a significant correlation was found between longitude, and P element susceptibility. The P and KP element were also characterized by polymerase chain reaction amplification. The molecular analyses showed that all the populations examined have the entire of 1.15 kb KP element. The molecular patterns of KP elements have been found similar between the populations studied.     

Genetic structure of South Australian Pyrenophora teres populations as revealed by microsatellite analyses

The aim of this study was to determine the genetic structure of South Australian field populations of the barley net blotch pathogens, Pyrenophora teres f. sp. teres (PTT) and P. teres f. sp. maculata (PTM), using microsatellite DNA markers. Three PTT populations (76 isolates total) and two PTM populations (43 isolates total) were sampled from separate fields during a single growing season. The results showed that of the 20 microsatellite loci examined, 17 (85 %) were polymorphic within the PTT and PTM populations. In total, 120 distinct alleles were identified of which only 11 (9 %) were shared between the two population types. Nei’s measure of gene diversity across the PTT and PTM populations was similar at 0.38 and 0.40, respectively, and also much higher than previously reported from studies in which other types of molecular markers were used. The coefficient of genetic differentiation among both populations was the same (G_ST = 0.03) and the low and insignificant estimates of F_ST, as indicated by θ, between populations of the same type (PTT: θ < 0.008, PTM: θ = 0.014) indicated that isolates sampled from different areas within the same field were genetically similar. In contrast, high and significant genetic differentiation was observed among and between populations of different type (G_ST = 0.42, θ > 0.567). The high number of unique multilocus haplotypes observed within the PTT (84 %) and PTM (100 %) populations, combined with a 1:1 distribution of both mating types, suggested that sexual reproduction was predominant among these populations. However, tests for multilocus associations showed that both PTT and PTM populations were in significant linkage disequilibrium. Although the levels of disequilibrium were low, an asexual reproductive component could not be excluded.     

Evaluation of the state of the gene pool of natural populations dwelling in the fragmented landscape of Moscow and Moscow region (with special reference to brown frogs)

A system of urban ecological genetic monitoring of vertebrates has been developed for the first time in Russia and in the world. As a model, two species of brown frogs, Rana arvalis Nilss. and R. temporaria L. (16 populations, seven isozyme loci) were used. An evaluation of the gene pool state in urban frog populations has shown that the diversity in the Moscow frog populations was lower than that in natural populations (up to 80 and 50% in respectively R. arvalis and R. temporaria). Mean heterozygosities per locus were higher in large natural populations than in small urban isolates: in R. arvalis, these values were 0.16 and 0.06; in R. temporaria, 0.34 and 0.18, respectively. The number of polymorphic loci was also higher in natural populations than in the urban ones: 4 versus 2 in R. arvalis and 5 versus 4 in R. temporaria. Using superoxiddismutase as an example, fixation of different alleles of the same locus in different small isolates was shown. The gene pool condition of all but one urban populations of brown frog was evaluated as unsatisfactory, and that of the R. arvalis populations, as critical. These changes of the gene pool are explained mainly by gene drift accompanied by inbreeding, which was caused by human-induced fragmentation of the range and a decrease in population size of the species. The results of this study was employed in the development of the Moscow governmental program on restoration of the gene pools of vanishing animal species on specially protected natural urban territories. The series of works on long-term monitoring and assessment of the state of natural populations of model species in anthropogenic landscapes of Moscow and Moscow region has laid a foundation for a new branch of science, gene urbanology.     

Seed protein and amino acid composition of WildVigna radiata var.sublobata (Fabaceae) and Two Cultigens,V. mungo andV. radiata

WildVigna radiata var.sublobata populations, inhabiting the mountains of India, and two cultigens,V. mungo andV. radiata, were examined for seed-protein content and amino acid composition. The protein content in the populations varied from 15.2 to 21%. Lysine, valine, isoleucine, leucine, phenylalanine, and tyrosine contents were invariably higher in wild populations as compared with the FAO reference pattern. The variation encountered in wild populations is largely genetic in origin. Total essential amino acids in the wild populations varied from 38.3 to 42.2; in the cultigens, from 29.2 to 37.5 (g/100 g protein). There was marked variation in the amino acid composition of the populations for the two different ecozones studied, suggesting a broad genetic base.