Biochemical genetic studies on wild populations of three species of green leafhoppers,Nephotettix, from peninsular Malaysia

Nine populations of three species ofNephotettix (Insecta: Hemiptera) from Peninsular Malaysia were analysed for nine enzymes comprising 11 loci. Nei's (Genetics 89, 583, 1978) genetic distance,D, betweenN. virescens andN. malayanus was 0.181, that betweenN. virescens andN. nigropictus was 0.283, and that betweenN. malayanus andN. nigropictus was 0.203. The genetic distance betweenN. nigropictus from rice plant and from the weed-grassL. hexandra at Universiti Pertanian Malaysia was 0.004 and their genetic identity was 0.996, thus indicating that this insect species feeds on both host plants. The proportion of polymorphic loci and the observed heterozygosities were higher inN. nigropictus, with a wider range of host plants, than inN. virescens andN. malayanus, restricted to rice andL. hexandra, respectively.     

Correlations between the ages of<Emphasis Type="Italic">Alnus</Emphasis> host species and the genetic diversity of associated endosymbiotic<Emphasis Type="Italic">Frankia</Emphasis> strains from nodules

Nodule samples were collected from four alder species:Alnus nepalensis, A. sibirica, A. tinctoria andA. mandshurica growing in different environments on Gaoligong Mountains, Yunnan Province of Southwest China and on Changbai Mountains, Jilin Province of Northeast China. PCR-RFLP analysis of the IGS betweennifD andnifK genes was directly applied to unculturedFrankia strains in the nodules. A total of 21 restriction patterns were obtained. TheFrankia population in the nodules ofA. nepalensis had the highest genetic diversity among all fourFrankia populations; by contrast, the population in the nodules ofA. mandshurica had the lowest degree of divergence; the ones in the nodules ofA. sibirica andA. tinctoria were intermediate. A dendrogram, which was constructed based on the genetic distance between the restriction patterns, indicated thatFrankia strains fromA. sibirica andA. tinctoria had a close genetic relationship.Frankia strains fromA. nepalensis might be the ancestor ofFrankia strains infecting otherAlnus species. From these results and the inference of the ages ofAlnus host species, it is deduced that there was a co-evolution betweenAlnus and its microsymbiontFrankia in China.     

Correlations between the ages ofAlnus host species and the genetic diversity of associated endosymbioticFrankia strains from nodules

Nodule samples were collected from four alder species:Alnus nepalensis, A. sibirica, A. tinctoria andA. mandshurica growing in different environments on Gaoligong Mountains, Yunnan Province of Southwest China and on Changbai Mountains, Jilin Province of Northeast China. PCR-RFLP analysis of the IGS betweennifD andnifK genes was directly applied to unculturedFrankia strains in the nodules. A total of 21 restriction patterns were obtained. TheFrankia population in the nodules ofA. nepalensis had the highest genetic diversity among all fourFrankia populations; by contrast, the population in the nodules ofA. mandshurica had the lowest degree of divergence; the ones in the nodules ofA. sibirica andA. tinctoria were intermediate. A dendrogram, which was constructed based on the genetic distance between the restriction patterns, indicated thatFrankia strains fromA. sibirica andA. tinctoria had a close genetic relationship.Frankia strains fromA. nepalensis might be the ancestor ofFrankia strains infecting otherAlnus species. From these results and the inference of the ages ofAlnus host species, it is deduced that there was a co-evolution betweenAlnus and its microsymbiontFrankia in China.

     

Genetic mapping of the polycystic kidney gene,pcy, on mouse chromosome 9

The murine polycystic kidney disease gene,pcy, is an autosomal recessive trait located on chromosome 9. To determine the genetic locus ofpcy, 222 intraspecific backcross mice were obtained by mating C57BL/6FG-pcy andMus molossinus. Restriction fragment length polymorphism analysis of 70 of the 222 backcross progeny showed thatpcy, dilute coat color (d), and cholecystokinin (Cck) were located in the orderd—pcy—Cck from the centromere. Simple sequence repeat length polymorphism analysis of DNA of all 222 backcross mice was carried out using four markers which were located near the central regions ofd andCck. One and eight recombinations were detected betweenD9Mit24 andpcy and betweenD9Mit16 andpcy, respectively. However, no recombinant was observed amongpcy, D9Mit14, andD9Mit148. These findings strongly suggest thatD9Mit14 andD9Mit148 are located near thepcy gene and are good markers for chromosomal walking to this gene.     

Allozyme diversity and systematics inAnnonaceae—a pilot project

Five species ofAnnona and one species fromArtabotrys, Cananga, Polyalthia, andRollinia were investigated in regard to 11 different allozyme loci. Preliminary studies on small population samples ofAnnona suggest genetic uniformity in three species and variability within and between populations in two other species. The allotetraploid origin ofA. glabra is clearly shown by its hybrid enzyme bands. The genetic distance between fiveAnnona species partly corresponds with their morphological relationships; onlyA. muricata appears more separated than is suggested by morphology. A comparison of the five genera demonstrates close relationship betweenAnnona andRollinia. Two enzyme loci are identical within all taxa investigated and possibly may serve as a genetic marker for the family.     

Species-specific banding patterns of restriction endonuclease-digested mitochondrial DNA from the genusPythium

Restriction endonuclease-digested mitochondrial DNA from 29Pythium spp. showed distinctly different species-specific electrophoretic banding patterns. Numerical comparisons among species were conducted by calculating the percentage of restriction fragments having the same apparent molecular size. The greatest interspecific similarity in banding patterns (67%) was observed betweenHindIII digests ofPythium heterothallicum andP. sylvaticum. However, comparisons among other species generally revealed similarities of less than 50%, and often less than 30%. The lack of similarity of restriction banding patterns was observed even with several species that share many common morphological features:P. arrhenomanes vsP. graminicola (20%),P. myriotylum vsP. aristosporum (28%), andP. torulosum vsP. vanterpoolii (32%). In contrast to the fragment size heterogeneity among different species, isolates of the same species have highly conserved restriction patterns. Ten isolates ofP. oligandrum, collected from the United States, South Africa, and Czechoslovakia, had a minimum of 86% similarity inHindIII banding patterns. Similar results were observed with eight isolates ofP. ultimum, five ofP. acanthicum, six ofP. spinosum, five ofP. sylvaticum, and eight ofP. irregulare. However, two isolates ofP. irregulare exhibited a higher degree of heterogeneity and shared only 64 to 76% comigrating bands with the eight other isolates of this species.     

Population studies in Goodyera (Orchidaceae) with emphasis on the hybrid origin of G. Tesselata

Morphological, cytological, and paper Chromatographic studies of populations from northern Michigan and examination of herbarium specimens from throughout North America were used to clarify the relationships ofGoodyera oblongifolia, G. repens var.ophioides, andG. tesselata. A canonical analysis of morphological data from mixed populations of these three species depictsG. tesselata as intermediate betweenG. oblongifolia andG. repens var.ophioides. The latter two species are diploid (2n = 30) andG. tesselata is tetraploid (2n = 60). Triploids (2n = ca. 45) were found in two mixed-species populations in northern Michigan.Goodyera tesselata produces three phenolic compounds present inG. oblongifolia and five different compounds present inG. repens var.ophioides. The range ofG. tesselata is confined to glaciated territory (except for two stations) in northeastern North America where the postglacially produced ranges ofG. oblongifolia andG. repens var.ophioides overlap. However,G. tesselata is quite abundant in areas outside the region of sympatry of the other two species. Based on this evidence, it is postulated thatG. tesselata is an allotetraploid species which resulted from hybridization betweenG. oblongifolia andG. repens var.ophioides during early post-Pleistocene. The slightly earlier blooming season ofG. tesselata may have been selected for to provide a measure of reproductive isolation between the tetraploid and its parents and to adapt the new species to the rather short growing season of northeastern North America.     

Hybridization in the babassu palm complex. II. Attalea compta × Orbignya oleifera (Palmae)

A new hybrid palm, ×Attabignya minarum, from the Rio São Francisco Valley of Minas Gerais, Brazil is described. It is a natural hybrid betweenAttalea compta Mart. andOrbignya oleifera Burret and is quite common in the area studied. Most of the morphological characters of the hybrid are intermediate between those of the parent species. A notable exception is the number of fruits produced; ×Attabignya minarum produces more fruits per panicle than either parent species. This is the first report of hybridization betweenOrbignya andAttalea and may shed light on the status ofOrbignya, considered by some to be synonymous withAttalea.     

Seed protein electrophoresis in sectionFoenum-graecum ofTrigonella (Fabaceae)

The seed proteins ofTrigonella foenum-graecum, T. berythaea, T. macrorrhyncha andT. gladiata were fractionated on polyacrylamide gels in anodic and cathodic systems. Similarity indices between the profiles of any two species indicated close affinity betweenT. gladiata andT. macrorrhyncha and betweenT. foenum-graecum andT. berythaea. It has been pointed out that according to morphological resemblance and similarity index of the seed protein profileT. berythaea is closer to the cultigen than any other species of sectionFoenum-graecum, but these two species are strongly isolated from one another by the albino seedlings of their F₁ hybrids.     

Numerical analysis of the taxonomical status ofCallithrix kuhli based on measurements of the postcanine dentition

The postcanine dentition ofCallithrix geoffroyi, Callithrix penicillata, andCallithrix kuhli was compared metrically to determine whetherC. kuhli is a hybrid population ofC. geoffroyi andC. penicillata or not. Many measurements showed significant differences (p<0.01 orp<0.05) among the three marmosets. The dental variability inC. kuhli was not greater than those inC. geoffroyi andC. penicillata. Based on canonical analysis, the three marmosets are discriminated, andC. kuhli did not occupy a middle position betweenC. geoffroyi andC. penicillata on the first two canonical axes. In the projection of the first two principal components,C. penicillata tended to be distinguished fromC. geoffroyi andC. kuhli, andC. kuhli does not exhibit intermediacy betweenC. geoffroyi andC. penicillata. The present statistical analysis failed to provide evidence thatC. kuhli constitutes a population hybridized fromC. geoffroyi andC. penicillata, although the three marmosets were discriminated from each other. This may provide support for the hypothesis thatC. kuhli is not a hybrid population ofC. geoffroyi andC. penicillata but a distinct species.     

Genetics of food preference inDrosophila sechellia

To reveal the genetic mechanism of host selection in a monophagous fruit flyDrosophila sechellia, olfactory responses and oviposition preferences of this species were compared with those of closely related polyphagous species,D. simulans andD. melanogaster. Adult flies ofD. sechellia were strongly attracted to the ripe fruit ofMorinda citrifolia which is known to be the sole breeding site of this species. They were also attracted to the odor ofn-caproic acid which is contained in the ripe fruit ofM. citrifolia and is presumably responsible for the characteristic odor of the fruit. In contrast,D. simulans andD. melanogaster showed a strong repulsion ton-caproic acid. In parallel with the olfactory responses,D. sechellia females laid eggs preferentially on a medium containingn-caproic acid, to which the other two species showed an aversion. Genetic analyses using the hybrid progeny betweenD. sechellia andD. simulans suggested that the species differences in these behaviors are controlled by gene(s) located on the second chromosome.     

A quantitative morphological classification of thirty species of cercospora

Twenty morphological characters of thirty species ofCercospora, collected in the Sudan, were used for a quantitative numerical classification. This revealed, 80% overall similarity betweenC. arisaemae onAbutilon sp. andC. gossypina onGossypium hirsutum, 75% overall similarity betweenC. cucurbitae onCucumis sativus andC. sesami onSesamum orientale and 75% overall similarity betweenC. gomphrenae onGomphrena globosa andC. coffeicola onCoffea robusta.This high level of morphological similarity suggests that these species may be conspecific and may cross — infect their respective hosts. Other species seemed to be fairly distinct.Formed part of M. Sc. Thesis submitted to Khartoum University.     

Karyotypic study of titi monkeys,Callicebus moloch brunneus

A karyotypic study on a subspecies of the dusky titi,Callicebus moloch brunneus, was carried out and a third karyotype ofC. moloch was discovered. The chromosome number of this subspecies is 48. The autosomes consist of 5 subtelocentric, 5 submeta- or metacentric, and 13 acrocentric chromosome pairs. The X chromosome and the Y chromosome are submetacentric and metacentric, respectively. A comparative study with other subspecies of theC. moloch group (i.e.,C. m. cupreus andC. m. ornatus with 2n=46 andC. m. donacophilus with 2n=50) suggests that the karyotype ofbrunneus occupies a position intermediate between the two other karyotypes ofC. moloch, but nearer to that of 2n=50. The presumed total differences betweenbrunneus andcupreus comprise one Robertsonian rearrangement, one centromeric transposition and four pericentric inversions, and those betweenbrunneus anddonacophilus involve one translocation or breakage (possibly corresponding to two events, that is, one Robertsonian rearrangement and one centromeric transposition).     

A biosystematic study of Coreopsis tinctoria and C. cardaminefolia (Compositae)

This paper presents evidence which leads the authors to propose the reduction ofCoreopsis cardaminefolia (DC.) Nutt. to synonymy underC. tinctoria Nutt.Coreopsis cardaminejolia andC. tinctoria overlap morphologically in all characters measured, except for winging vs. non-winging of the achenes. The winging character is shown to be dependent upon segregation at one or two loci. Both “species” have chromosome numbers of 2n = 24 and 2n = 26. The basic number isx = 12, with some plants showing a supernumerary pair of chromosomes, which apparently undergo post-meiotic preferential distribution on both the maternal and paternal sides. The two taxa overlap extensively in range and occupy the same habitat, rather commonly occurring in mixed colonies.Coreopsis tinctoria is redefined to include the intrapopulational variation heretofore designatedC. cardaminefolia.     

Gene variation and gene flow inOrchis morio (Orchidaceae) from Italy

Data are presented on genetic variation at 27 enzyme loci of the Green-Winged orchid,Orchis morio, in 18 population samples from Italy. The existence in Italy of two subspecies, i.e. subspp.morio andpicta, is not supported by allozyme data. No genetic heterogeneity was found betweenmorio-like andpicta-like samples and specimens. Moreover, morphological transition between the two forms was observed in different Italian populations. The parameters of genetic variability estimated forO. morio populations are consistent with those found among monocotyledon plants, and among those outcrossing, animal-pollinated and with wind-dispersed seeds. Genetic diversity of ItalianO. morio is mostly within populations. Correspondingly, low values of interpopulational genetic distance were found. This appears to be due to high levels of gene flow, which were estimated with different methods. The lack ofO. longicornu from Italian samples, as well as of any hybrid withO. morio (F₁, backcrossed or recombinant individuals) is demonstrated on the basis of genetic data. It is concluded that recurrent reports ofO. longicornu from Italy are due to confusion withO. morio or with otherOrchis species.     

Larval and adult morphology ofCamallanus anabantis Pearse, 1933 andC. kulasirii (Yeh, 1960) (Nematoda: Camallanidae) from freshwater fishes,with notes on the validity of some related forms

Larvae and adults ofCamallanus anabantis andC. kulasirii, recovered from the West Bengali freshwater fishes,Anabas testudineus andOphicephalus punctatus, respectively, are described on the basis of detailed morphological studies under the light microscope. Larval forms collected fromA. testudineus are deemed to be of the third and fourth stages when compared with those from experimental studies of the life cycle ofC. anabantis. Moreover, the present fourth stage female larvae are similar to the females ofC. pearsei, both morphologically and metrically.C. pearsei is, therefore, believed to represent the fourth stage female larvae ofC. anabantis. Similarly, adult males and females recovered fromO. punctatus closely resembleC. kulasirii andC. fernandoi, respectively. The larval forms from this host are fourth stage and can be distinguished as males and females, but both possess a buccal capsule bearing beaded longitudinal ridges similar to that of adult males. The late fourth stage (just prior to the final moult) female larva is, however, found to possess a buccal capsule transitional between that of the adult male and female and also betweenC. kulasirii andC. fernandoi. C. fernandoi is, therefore, presumed to represent the females ofC. kulasirii. However,C. pearsei andC. fernandoi are regarded, for the present, asspecies inquirendae.     

Polymorphisms of alcohol metabolizing enzyme and cytochrome P4502E1 genes in mongolian population

Although the genetic polymorphism of the alcohol-metabolizing enzymes was extensively studied at the molecular level by many investigators, the genetic polymorphism studies for ethanolmetabolizing enzymes in Mongolians are very rare. The present study was therefore performed to determine the genetic distribution of various forms of alcohol-metabolizing enzymes such as alcohol dehydrogenase 2 (ADH2, currently accepted nomenclature ADH1B), ADH3 (ADH1C), aldehyde dehydrogenase 2 (ALDH2) and cytochrome P4502E1 (CYP2E1) in 300 healthy Mongolian males. Genetic polymorphisms were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) methods. The allele frequencies ofADH2 *1 andADH2 *2 were 0.24 and 0.76;ADH3 *1 andADH3 *2 were 0.92 and 0.08;ALDH2 *1 andALDH2 *2 were 0.96 and 0.04; andCYP2E1 *C andCYP2E1 *D were 0.15 and 0.85, respectively. Compared to the results reported by other investigators, the allele frequencies ofALDH2 *2 andCYP2E1 *C among Mongolian subjects were much lower than among East Asians (Korean, Japanese, and/or Han-Chinese), while those ofADH2 andADH3 were more similar. Interestingly, this study shows that the ineffectiveALDH2 gene (ALDH2*2 allele) among Mongolians is not as common as among East Asians.     

Leaf flavonoid chemistry of Coreopsis (Compositae) section Palmatae

Examination of leaf flavonoids of all taxa ofCoreopsis sectionPalmatae revealed that most members synthesize an array of common flavone (mostly luteolin and apigenin) glycosides. Each diploid species or diploid member of a species is characterized by a particular ensemble of compounds. These taxa includeC. major, C. verticillata, C. pulchra, C. palmata, andC. tripteris. The latter species differs from all other taxa in producing flavonol (kaempferol and quercetin) glycosides and what appear to be 6-oxygenated compounds. Tetraploids ofC. verticillata exhibit the same flavonoids as diploid members of the species, thus flavonoid chemistry supports the hypothesis that they originated from diploids within the species. Certain populations of hexaploid and octoploidC. major are similar chemically to diploids, suggesting they also originated as intraspeciflc polyploids. Other populations of these polyploids exhibit a flavonoid profile which differs from the profile of the diploids, and this profile is nearly identical to the octoploidCoreopsis × delphinifolia. The latter taxon has been viewed by Smith (1976) and Mueller (1974) as an interspecific hybrid betweenC. verticillata andC. major and/orC. tripteris. Species-specific compounds from the former species occur inC. × delphinifolia but no compounds unique to either of the latter two species are discernable. Flavonoid chemistry is not useful in ascertaining whether either or both species have been involved withC. verticillata in producing plants referable toC. × delphinifolia. There is morphological intergradation between octoploidC. major andC. × delphinifolia, and all plants not appearing to be “pure”C. major exhibit a flavonoid chemistry likeC. × delphinifolia. All plants of sectionPalmatae considered to be alloploids (includingC. × delphinifolia) produce the same array of leaf flavonoids, including several “novel” compounds not expressed in the putative parental taxa. Two of the “novel” flavonoids are present in the geographically restricted diploidC. pulchra. The systematic and phylogentic significance of this is not readily apparent.     

Low genetic differentiation betweenAdiantum capillusveneris L. andA. ogasawarense Tagawa (Adiantaceae), an endemic pteriodophyte of the bonin (ogasawara) islands

Genetic differentiation was examined betweenAdiantum capillus-veneris L. andA. ogasawarense Tagawa. A total of 136 individuals from two populations ofA. ogasawarense and three populations ofA. capillus-veneris were sampled. Allozymes encoded by 19 putative loci for nine enzyme systems were observed. The populations ofA. ogasawarense are genetically differentiated from those ofA. capillus-veneris; conspecific populations cluster together. However, genetic identity between two species was estimated to be 0.815, and indicates that the degree of allozyme differentiation is lower than those between endemic flowering plants and their progenitors. It is possible that the low genetic differentiation observed betweenA. ogasawarense andA. capillus-veneris results from a recent origin of the endemic species,A. ogasawarense.