The ethnic minorities of southern Italy and Sicily: relationships through surnames

Surnames of grandparents were collected from children in the primary schools of the Albanian-Italian, Croat-Italian and Greek-Italian villages of southern Italy and Sicily. The coefficients of relationships by isonymy show almost no relationship with ethnicity. Ethnolinguistic minorities of southern Italy and Sicily are geographically subdivided into two main clusters: the first cluster comprises the Albanian, Croat and Greek communities of the Adriatic area; and the second cluster comprises the Albanian and Greek communities of the Ionian, Thirrenian and Sicilian areas.     

Genetic relationships between parishes in the Ebro delta region (Spain) as estimated by migration matrix and surnames

To determine whether there are preferential relationships among individuals from the different parishes of the Ebro River delta region, we analyzed the population relationships, taking into account both the birthplaces of the spouses and their surname frequencies. We used data from the 9,085 marriages recorded in the Ebro delta area between 1939 and 1995. Using each spouse's birthplace, we calculated the distances between the subject populations by means of the squared Euclidean distance. Also, from the surname frequencies in the marriages we obtained certain kinship measurements. In both analyses the results show a clear differentiation between the parish of Amposta and the rest of the parishes. This difference is mainly due to a greater number of marriages in which delta outsiders participated and can be related to the greater surname diversity and lesser endogamy observed in this population. On the other hand, if only endogamous marriages are taken into account, there is clearly a differentiation between the parishes from both banks of the river, with a strong homogeneity among the northside parishes. We compared the distances obtained from the birthplaces, the kinship parameters obtained from the surnames, and two geographic distance matrixes by means of a Mantel test, and the results show a strong and significant correlation between them when all marriages are considered. If, on the other hand, only endogamous marriages are taken into account, the barrier effect of the river on the interparish relationships can be appreciated.     

Genetic diversity among wild and cultivated barley as revealed by RFLP

Genetic variability of cultivated and wild barley, Hordeum vulgare ssp. vulgare and spontaneum, respectively, was assessed by RFLP analysis. The material consisted of 13 European varietes, single-plant offspring lines of eight land races from Ethiopia and Nepal, and five accessions of ssp. spontaneum from Israel, Iran and Turkey. Seventeen out of twenty-one studied cDNA and gDNA probes distributed across all seven barley chromosomes revealed polymorphism when DNA was digested with one of four restriction enzymes. A tree based on genetic distances using frequencies of RFLP banding patterns was estimated and the barley lines clustered into five groups reflecting geographical origin. The geographical groups of land-race lines showed less intragroup variation than the geographical groups of spontaneum lines. The group of European varieties, representing large variation in agronomic traits, showed an intermediate level. The proportion of gene diversity residing among geographical groups (F_ST) varied from 0.19 to 0.94 (average 0.54) per RFLP pattern, indicating large diversification between geographical groups.     

Genetic structure through surnames in Campobasso Province, Italy

The population of Campobasso Province shows a level of inbreeding that is distinct from most Italian rural populations, regardless of their geographic location (Fr=0.0040; Fn=0.0102; Ft=0.0142). The genetic structure of the Italian-Greek communities of Lecce and Reggio Calabria Provinces does not appear to be affected by ethnicity. The level of inbreeding in Italian-Greeks of Reggio Calabria Province is similar to other Italians of Campobasso Province (Fr=0.0041; Fn=0.0127; Ft=0.0168). The Italian-Greeks of Lecce Province show random mating, and their inbreeding is in fact very low (Fr=0.0038; Fn=0.0024; Ft=0.0062).     

Genetic relationships among Stylosanthes species as revealed by sequence-tagged site markers

 Nineteen sequence-tagged site (STS) primer pairs were designed on coding and non-coding regions in nine published Stylosanthes genes, which were mostly derived from cDNA. Direct sequencing of PCR products derived from genomic DNA allowed us to identify introns and to design specific primers flanking these introns. The use of 24 STS primer pairs for the detection of intra- and inter-specific variation in Stylosanthes based on size differences was tested on a core set of Stylosanthes species. Based on these results, 20 STS markers were selected to determine genetic relationships among 63 genotypes representing 24 Stylosanthes species. A total of 148 alleles were amplified and analyzed, resulting in a genetic similarity value ranging from 0.62 to 0.98 among the species. Based on cluster analysis, three main groups and three subgroups were determined, and most of the species were classified unambiguously. Alloploid species were recognized by the occurrence of more than one allele per STS marker, indicating fixed heterozygosity. Sixteen STS markers were useful for the identification of genotypes within a species. Inter-species relationships, as revealed by STS, were in general agreement with previous morphological and molecular relationship studies. These STS markers are useful as an additional tool for the identification of species, subspecies and genotypes in Stylosanthes, with a view to plant conservation and breeding. Received: 2 June 1998 / Accepted: 28 October 1998     

Genetic diversity and differentiation in Dalbergia sissoo (Fabaceae) as revealed by RAPD

Dalbergia sissoo, a wind-dispersed tropical tree, is one of the most preferred timber tree species of South Asia. Genetic diversity and differentiation among natural populations of D. sissoo were examined for the first time. We found a relatively high level of genetic diversity in D. sissoo, both at the species level (percentage of polymorphic bands = 89.11%; H = 0.2730; I = 0.4180) and the population level (percentage of polymorphic bands = 68.7%; H = 0.239; I = 0.358), along with a relatively low degree of differentiation among populations (GST = 0.1311; AMOVA = 14.69%). Strong gene flow among populations was estimated, N(m) = 3.3125. The Mantel test suggested that genetic distances between populations were weakly correlated with geographic distances (R = 0.3702, P = 0.1236). The high level of genetic diversity, low degree of differentiation, strong gene flow, and weak correlation between genetic and geographic distances can be explained by its biological character and wide-spread planting. This information will be useful for the introduction, conservation and further studies of D. sissoo and related species.     

Genetic diversity of Carica papaya as revealed by AFLP markers.

Genetic relationships among Carica papaya cultivars, breeding lines, unimproved germplasm, and related species were established using amplified fragment length polymorphism (AFLP) markers. Seventy-one papaya accessions and related species were analyzed with nine EcoRI-MseI primer combinations. A total of 186 informative AFLP markers was generated and analyzed. Cluster analysis suggested limited genetic variation in papaya, with an average genetic similarity among 63 papaya accessions of 0.880. Genetic diversity among cultivars derived from the same or similar gene pools was smaller, such as Hawaiian Solo hermaphrodite cultivars and Australian dioecious cultivars with genetic similarity at 0.921 and 0.912, respectively. The results indicated that self-pollinated hermaphrodite cultivars were as variable as open-pollinated dioecious cultivars. Genetic diversity between C. papaya and six other Carica species was also evaluated. Carica papaya shared the least genetic similarity with these species, with an average genetic similarity of 0.432; the average genetic similarity among the six other species was 0.729. The results from AFLP markers provided detailed estimates of the genetic variation within and among papaya cultivars, and supported the notion that C. papaya diverged from the rest of Carica species early in the evolution of this genus.     

Drift as a mechanism for cultural change: an example from baby names

In the social sciences, there is currently no consensus on the mechanism by which cultural elements come and go in human society. For elements that are value-neutral, an appropriate null model may be one of random copying between individuals in the population. We show that the frequency distributions of baby names used in the United States in each decade of the twentieth century, for both males and females, obey a power law that is maintained over 100 years even though the population is growing, names are being introduced and lost every decade and large changes in the frequencies of specific names are common. We show that these distributions are satisfactorily explained by a simple process in which individuals randomly copy names from each other, a process that is analogous to the infinite-allele model of population genetics with random genetic drift. By its simplicity, this model provides a powerful null hypothesis for cultural change. It further explains why a few elements inevitably become highly popular, even if they have no intrinsic superiority over alternatives. Random copying could potentially explain power law distributions in other cultural realms, including the links on the World Wide Web.     

Genetic variability and differentiation of Caragana microphylla populations as revealed by RAPD markers

Genetic variability in random amplified polymorphic DNA (RAPD) was studied in 90 individuals of Caragana microphylla, an outcrossing perennial shrub species, from five natural populations sampled in Inner Mongolia steppe of China on a small scale. Nineteen selected primers were used to amplify DNA samples, and totally 225 bands were detected. The percentage of polymorphic bands within populations ranged form 58.22% to 63.56%, with an average of 60% at the population level and 71.11% at the species level, indicating relatively high genetic variations in C. microphylla species. Shannon's information index (I) and Nei's gene diversity (h) showed the similar trend with each other. According to the analysis of Nei's gene diversity, the percentage of genetic variation among populations was 7.13%, indicating a low level of genetic differentiation among populations. There existed a strong gene flow (Nm = 3.26) among populations. Although AMOVA analysis also revealed most variation was within populations (phi(ST) = 4.1%), a significant proportion was observed among populations (P<0.001) in the present study, suggesting genetic differentiation occurred among populations at a certain extent. Based on Mantel's tests and the results of previous studies, the genetic structure pattern of C. microphylla accorded with the isolation-by-distance model on a very large scale, however, on a small scale, the significant genetic differentiation among populations might be enhanced by the micro-environmental divergence among the sampling sites, rather than by geographic factors. Analysis of the genetic variations of C. microphylla populations provided useful information for the adaptive strategy of Caragana species.     

Human development and cultural transmission

Transmission of cultural knowledge to children takes several forms. This paper argues that there are three basic forms of cultural transmission, which are introduced sequentially at different stages of development. Earlier forms are retained as new ones are added, and all three forms are used in adult cultural transmissions. The introduction of new forms is made possible by the cognitive and behavioral consequences of neurological and hormonal changes in the developing body.     

Genetic structure of Hmong-Mien speaking populations in East Asia as revealed by mtDNA lineages

Hmong-Mien (H-M) is a major language family in East Asia, and its speakers distribute primarily in southern China and Southeast Asia. To date, genetic studies on H-M speaking populations are virtually absent in the literature. In this report, we present the results of an analysis of genetic variations in the mitochondrial DNA (mtDNA) hypervariable segment 1 (HVS1) region and diagnostic variants in the coding regions in 537 individuals sampled from 17 H-M populations across East Asia. The analysis showed that the haplogroups that are predominant in southern East Asia, including B, R9, N9a, and M7, account for 63% (ranging from 45% to 90%) of mtDNAs in H-M populations. Furthermore, analysis of molecular variance (AMOVA), phylogenetic tree analysis, and principal component (PC) analysis demonstrate closer relatedness between H-M and other southern East Asians, suggesting a general southern origin of maternal lineages in the H-M populations. The estimated ages of the mtDNA lineages that are specific to H-M coincide with those based on archeological cultures that have been associated with H-M. Analysis of genetic distance and phylogenetic tree indicated some extent of difference between the Hmong and the Mien populations. Together with the higher frequency of north-dominating lineages observed in the Hmong people, our results indicate that the Hmong populations had experienced more contact with the northern East Asians, a finding consistent with historical evidence. Moreover, our data defined some new (sub-)haplogroups (A6, B4e, B4f, C5, F1a1, F1a1a, and R9c), which will direct further efforts to improve the phylogeny of East Asian mtDNAs.     

Genetic diversity among summer and winter Beauveria bassiana populations as revealed by AFLP analysis

The genetic diversity of Beauveria bassiana was investigated by comparing 40 isolates collected from summer and overwintering populations of Sunn pest from different areas in Syria and Turkey, using amplified fragment length polymorphism (AFLP) markers. Considerable genetic variability among B. bassiana isolates was revealed. The examined isolates were divided into three distinct clusters (A, B, and C). Within these clusters, the summer isolates from Syria and Turkey were grouped together in three sub-clusters (A3, A4, and B2). Also, principal coordinate analyses (PCA) showed clear separation (62.5%) between summer and winter isolates. These differences in the genetic structure may be explained by the variety of eco-geography over the sampled areas of B. bassiana isolates. This information on genetic variation among summer and winter B. bassiana isolates is helpful in designing an effective integrated pest management program for Sunn pest.     

Genetic diversity in cocoa revealed by cDNA probes

The variability of the cocoa (Theobroma cacao) nuclear genome was investigated. A total of 203 cocoa clones was surveyed for restriction fragment length polymorphisms (RFLPs) using four restriction endonuclease and 31 seed cDNA probes. A high level of polymorphism has been found. This study points to a structuring of the species that fits with the distinction between the Criollo and Forastero populations. These results combined with previously obtained nuclear rDNA and mtDNA data allow us to propose new hypotheses on the origin and evolution of the different cocoa populations.     

Genetic variation and relationship among and within Withania species as revealed by AFLP markers.

Withania somnifera is an important medicinal plant, and its anticancerous properties have been attributed to various classes of withanolide compounds. The objective of the present study was to investigate the inter- and intraspecific genetic variation present in 35 individuals of W. somnifera and 5 individuals of W. coagulans using AFLP (amplified fragment length polymorphism) marker technique. The information about genetic variation determined from AFLP data for 40 individuals was employed to estimate similarity matrix value based on Jaccard's coefficient. The similarity values were further used to construct a phenetic dendrogram revealing the genetic relationships. The dendrogram generated by UPGMA (unweighted pair group method of arithmetic averages) distinguished W. somnifera from W. coagulans and formed two major clusters. These two main clusters shared a similarity coefficient of 0.3, correlating with the high level of polymorphism detected. The dendrogram further separated W. somnifera into three subclasses corresponding to Kashmiri and Nagori groups and an intermediate type. The AFLP profile of Kashmiri individuals was distinct from that of the Nagori group of plants. The intermediate genotype was distinct as it shared bands with both the Kashmiri and Nagori individuals, even though it was identified as a Kashmiri morphotype. Furthermore, the intermediate type shared a similarity coefficient of 0.8 with the Kashmiri individuals. The present work revealed low levels of variation within a population though high levels of polymorphism were detected between Nagori and Kashmiri populations. The ability of AFLP markers for efficient and rapid detection of genetic variations at the species as well as intraspecific level qualifies it as an efficient tool for estimating genetic similarity in plant species and effective management of genetic resources.     

Genetic diversity in Elymus caninus as revealed by isozyme, RAPD, and microsatellite markers.

Genetic diversity of 33 Elymus caninus accessions was investigated using isozyme, RAPD, and microsatellite markers. The three assays differed in the amount of polymorphism detected. Microsatellites detected the highest polymorphism. Six microsatellite primer pairs generated a total of 74 polymorphic bands (alleles), with an average of 15.7 bands per primer pair. Three genetic similarity matrices were estimated based on band presence or absence. Genetic diversity trees (dendrograms) were derived from each marker technique, and compared using Mantel's test. The correlation coefficients were 0.204, 0.267, and 0.164 between isozyme and RAPD distance matrices, RAPD and microsatellite distance matrices, and between isozyme and microsatellite distance matrices, respectively. The three methodologies gave differing views of the amount of variation present but all showed a high level of genetic variation in E. caninus. The following points may be drawn from this study whether based on RAPD, microsatellite, or isozyme data: (i) The Icelandic populations are consistently revealed by the three dendrograms. The congruence of the discrimination of this accession group by RAPD, microsatellite, and isozyme markers suggests that geographic isolation strongly influenced the evolution of the populations; (ii) The degree of genetic variation within accessions was notably great; and (iii) The DNA-based markers will be the more useful ones in detecting genetic diversity in closely related accessions. In addition, a dendrogram, which took into account all fragments produced by isozymes, RAPDs, and microsatellites, reflected better the relationships than did dendrograms based on only one type of marker.     

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.     

Genetic architecture of photosynthesis energy partitioning as revealed by a genome-wide association approach

Photosynthesis Research - The photosynthesis process is determined by the intensity level and spectral quality of the light; therefore, leaves need to adapt to a changing environment. The incident...     

Genetic diversity and its relationship to hybrid performance and heterosis in rice as revealed by PCR-based markers

Ten elite inbred lines (four japonica, six indica), chosen from those widely used in the hybrid rice breeding program at Human Hybrid Rice Research Center in China, were crossed to produce all possible hybrids excluding reciprocals. The 45 F₁ hybrids along with the ten parents were evaluated for eight traits of agronomic importance, including yield potential, in a replicated field trial. The ten parents were analyzed with 100 arbitrary decamer oligonucleotide primers and 22 microsatellite (simple sequence repeats, SSRs) primer sets via polymerase chain reaction (PCR). Out of the 100 random primers used, 74 were informative and amplified 202 non-redundant bands (variants) with a mean of 2.73 bands per polymorphic primer. All 22 microsatellite primer sets representing 23 loci in the rice genome showed polymorphisms among the ten parents and revealed 90 alleles with an average of 3.91 per SSR locus. Cluster analysis based on Nei's genetic distance calculated from the 291 (202 RAPDs, 89 SSRs) non-redundant variants separated the ten parental lines into two major groups that corresponds to indica and japonica subspecies, which is consistent with the pedigree information. Strong heterosis was observed in hybrids for most of the traits examined. For the 43 diallel crosses (excluding 2 crosses not heading), yield potential, its components (including panicles per plant, spikelets per panicle and 1000-grain weight) and their heterosis in F₁ hybrids showed a significant positive correlation with genetic distance. When separate analyses were performed for the three subsets, yield potential and its heterosis showed significant positive correlations with genetic distance for the 15 indica x indica crosses and the 6 japonica x japonica crosses; however, yield potential and its heterosis were not correlated with genetic distance for the 22 indica x japonica crosses. Results indicated that genetic distance measures based on RAPDs and SSRs may be useful for predicting yield potential and heterosis of intra-subspecific hybrids, but not inter-subspecies hybrids.     

Lateral connections between heart muscle cells as revealed by conventional and high voltage transmission electron microscopy

Summary The lateral surfaces of heart muscle cells are interconnected by a varied and extensive network of structures that exist in addition to intercalated discs. Ultrastructural images of this network are vastly improved over those from epoxy-embedded material, particularly for low density components, through the application of a method for removing the embedding matrix from thin or thick sections that are then stereoscopically analyzed with standard or high voltage transmission electron microscopy. The connections include cables, 3–20 nm in diameter, multi-strand cables, 10–40 nm-granules, meshlike mats, and sheets, all extensively interwoven. It is suggested that intercellular connections of varying strength and distribution aid in the integration of mechanical performance of the large population of myocytes during the contractile cycle of the heart.This study was supported by a grant from NIH Biotechnology Resources through the University of Colorado High Voltage E.M. Laboratory, NIH Research Grant HL 24336, a N.Y. Heart Association Grant-in-Aid, and NIH Research Career Development Award HL 00568I thank Dr. E.H. Sonnenblick for continual aid and encouragement and Dr. R. Terry, Ms. Y. Kress, and Ms. J. Fant for use of facilities. I also thank Dr. K.R. Porter for guidance in the use of the HVEM technique, Dr. J.J. Wolosewick and Dr. M. Fotino for valuable suggestions, and Ms. J. Fleming, Mr. G. Wray, and Mr. G. Charlie of HVEM staff at Boulder. I acknowledge Dr. F. Pepe for use of facilities, Dr. R. Bloodgood for comments, and Mrs. L. Cohen-Gould, Ms. T. Downey, Mr. F. Reingold, Mrs. T. Maio, and Mrs. R. Shamoon for excellent assistance     

Genetic diversity and differentiation of Indian isolates of Phytophthora infestans as revealed by RAPD analysis

Sixty-seven isolates of Phytophthora infestans collected from Himalayan hill regions and subtropical planes of India were characterized by RAPD markers to assess diversity and differentiation based on location of origin. Ten random decamer primers generated 161 polymorphic fragments. Association of P. infestans isolates on the dendrogram and PCO plot revealed two clear grouping based on geographical location of origin-hill isolates and plane isolates. Quantification of diversity by Shannon index of diversity analysis demonstrated that most of the diversity was present with a particular population (hill or plane) of P. infestans isolates, with 85% variation being within and 15% being between hill and plane isolates. Subtropical plane isolates of P. infestans exhibited higher variability compared to hill isolates and they were more dispersed on the PCO plot. No clear differentiation of isolates based on mating type was reflected on the dendrogram and PCO plot.