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At least 91 records · Page 5Linked to original sources
PubMed2001

Molecular approaches to the taxonomic position of Peruvian potato cyst nematodes and gene pool similarities in indigenous and imported populations of Globodera.

Peruvian potato cyst nematode populations were analysed to assess both their inter- and intraspecific similarities. ITS--RFLP and two satellite DNA sequences were used as taxonomic tools. Both techniques have confirmed that the Peruvian populations have as their closest relatives the European Globodera pallida, despite the detection of clear differences that prevents us from assigning these South American populations unambiguously to any Globodera species. A more precise study of the variability of these Peruvian populations was investigated and they were compared with the imported European populations using protein (2-DGE) and DNA (RAPD) datasets. The clear distinction between the Peruvian and the European populations was confirmed and, inside each group, no correlation was found between the pathotype classification and the observed clustering of the populations. Surprisingly, while RAPDs revealed a higher variability in the Peruvian group than in the European one, some characteristic proteins were found by 2-DGE in some European populations, whereas it was impossible to find any in the Peruvian populations. It is concluded that the primary founders of the European populations may have an origin other than that of the Peruvian populations involved in this study.

Animals↗
PubMed1996

Gene pool similarities of potato cyst nematode populations assessed by AFLP analysis.

AFLP was used to characterize 24 potato cyst nematode populations. This novel DNA fingerprinting technique enabled the identification of 987 marker loci by screening only 12 primer combinations. Data on presence or absence polymorphisms and data on the intensities of corresponding DNA fragments were collected. Separate analysis of both data sets revealed similar dendrograms for the nine G. rostochiensis populations included in this study. Both dendrograms consisted of two groups containing three and five related populations, respectively. One population differed from either of these groups. Each group represented a different pathotype as defined by Kort et al. (J. Kort, H. Ross, H. J. Rumpenhorst, and A. R. Stone, Nematologica 23:333-339, 1977). Previously, a similar arrangement was found after analysis of the genetic variation using random amplified polymorphic DNA (RAPD) (R. T. Folkertsma, J. N. A. M. Rouppe van der Voort, M. P. E. van Gent-Pelzer, K. E. de Groot, W. J. van den Bos, A. Schots, J. Bakker, and F. J. Gommers, Phytopathology 84:807-811, 1994). For the 15 G. pallida populations analyzed, complex AFLP patterns were obtained and therefore only qualitative AFLP data were used. Incongruities were observed between clustering on the basis of AFLP data and classical pathotyping. This strongly confirms earlier findings obtained with RAPDs, because the AFLP markers used in this study outnumbered the population characteristics revealed by RAPDs by a factor of five. To arrive at a reliable pathotype designation of potato cyst nematode populations molecular data and virulence characteristics should be integrated. Possible causes for the difference in distribution of polymorphisms among g. rostochiensis and G. pallida populations are discussed.

Animals↗
PubMed2006

Haplotype structure at seven barley genes: relevance to gene pool bottlenecks, phylogeny of ear type and site of barley domestication.

Archaeological remains indicate that the origin of western agriculture occurred in a brief period about 10,500 years ago in a region of the Middle East known as the Fertile Crescent, where the wild progenitors of several key agricultural cereal species are endemic. Domestication entailed the appearance of agronomic traits such as seed size and threshability. For a representative sample of 20 domesticated barley (Hordeum vulgare) lines, including 13 two-rowed and 7 six-rowed varieties, we determined the haplotypes at seven loci-Adh2, Adh3, Amy1, Dhn9, GAPDH, PEPC and WAXY encompassing 5,616 bases per line-and compared them to the haplotypes at the same loci for 25 wild forms (Hordeum spontaneum) collected within and outside the Fertile Crescent. In comparisons of wild versus domesticated barley, the number of haplotypes (70 vs. 17), average nucleotide diversity, pi, (0.0077 vs. 0.0028), and Watterson's theta at silent sites (0.0104 vs. 0.0028) was reduced in domesticated lines. Two loci, Amy1 and PEPC, were monomorphic in domesticated lines; Amy1 and GAPDH produced significant values of Tajima's D. At GAPDH, pi was slightly higher in domesticated than wild forms, due to divergent high-frequency haplotypes; for the remaining six loci, 87% of nucleotide diversity has been lost in the domesticated forms. Bottlenecks acting on neutrally evolving loci either during the domestication process, during subsequent breeding, or both, are sufficient to account for reduced diversity and the results of Tajima's test, without the need to evoke selection at these loci. Phylogenetic networks data uncover distinct wild and domesticated barley genotypes and suggest that barley may have been domesticated in the Jordan valley. Because, based on AFLP data, the domesticated Turkish cultivars had a genetic basis as large as that present in large germplasm collections, all comparisons provided in this paper are of general value more than being restricted to the Turkish barley germplasm.

Agriculture↗
PubMed1998

[Computer technology for genogenographic study of the gene pool. V. Evaluation of the reliability of maps].

An important aspect of gene geography, the estimation of the reliability of interpolation maps, is considered. The introduced quantitative parameter, map reliability, was estimated as the probability of predicted character values in interpolated map regions. The obtained estimates characterize the statistic significance of the mapped values of the character. The estimation algorithm is based on concepts and mathematical methods of the reliability theory. The proposed approach involved the estimation of the reliability at each point of the mapped area and resulted in a new map (a reliability map) expressing the reliability of gene geographic mapping in probability terms. Approaches to estimate the reliability of mapping, as dependent on various parameters of the initial data, were proposed, a general computer-based technology was elaborated, and a standardized reliability scale was proposed. Reliability maps are considered necessary for the correct interpretation of gene geographic maps. The estimation of reliability as dependent on the number and distribution of initially tested populations was illustrated by the example of frequency maps of individual genes (HP*1, HLA*A1) and synthetic maps (100 alleles of 34 polymorphic loci) of Eastern Europe.

Algorithms↗
PubMed1994

[Materials on the study of the gene pool of peoples of Russian and adjacent countries. Russian residents of the Tversk region].

An investigation was performed on the distribution of the gene and haplotype frequencies of A1A2B0, Rh, MNSs, Lewis, P1, Duffy, Kell-Cellano, Kell-Kp, Sutter, Kidd, Lutheran, Hp, Gc, Tf, C'3, Pi, GLO1, EsD, AcP, 6-PGD, PGM1 (subtypes), PTC, and CB loci, and on ABH-antigen secretion in the native Russian population of four rural districts of Tver' oblast'. The following peculiarities of genetic structure of the studied groups were revealed: a higher incidence of A1, A2, MS, NS, Ns, CDE, cDe, cdE, le, se, and K genes and haplotypes, in comparison to the average for Russians; and a lower incidence of cDE, CDe, cde, Jka, AcPa, AcPc, t, and CB+ genes and haplotypes. The incidence of other studied genes and haplotypes coincides with the average ethnic frequencies for Russians.

Ethnicity↗
PubMed1983

[The role of the population gene pool in meningococcal infection morbidity].

The character of the distribution of HLA antigens in patients with meningococcal infection among Russians and Touvinians was revealed. The markers of susceptibility to meningococcal infection were detected in each national group. These markers were HLA-Bw22 in Touvinians. The gene of susceptibility to meningococcal infection occurred among Touvinians 2.3 times more frequently. This was probably the cause of a higher morbidity rate in meningococcal infection among Touvinians than among Russians.

Child↗
PubMed1994

[Materials on studying the gene pool of populations from Russian and adjacent countries: the Russian population of the Vologda region].

An investigation was performed on the distribution of frequencies of A1A2B0, Rhesus, MNSs, P, Lewis, Kell-Cellano, Kell-Kp, Sutter, Lutheran, Hp, Gc, Tf, C'3, Pi, GLO1, EsD, AcP, 6-PGD, PGM1 (subtypes), PTC, and CB gene markers in the native Russian population of three rural districts of Vologda oblast'. Peculiarities of the genetic structure of the population of Vologda oblast' were revealed and compared to other groups of the Russian population.

Gene Pool↗
PubMed2005

Exploring the microbial biodegradation and biotransformation gene pool.

Similar to the New World explorers of the 16th and 17th century, microbiologists today find themselves at the edge of unknown territory. It is estimated that only 0.1-1% of microorganisms can be cultivated using current techniques; the vastness of microbial lifestyles remains to be explored. Because the microbial metagenome is the largest reservoir of genes that determine enzymatic reactions, new techniques are being developed to identify the genes that underlie many valuable chemical biotransformations carried out by microbes, particularly in pathways for biodegradation of recalcitrant and xenobiotic molecules. Our knowledge of catabolic routes built on research during the past 40 years is a solid basis from which to venture on to the little-explored pathways that might exist in nature. However, it is clear that the vastness of information to be obtained requires astute experimental strategies for finding novel reactions.

Bacteria↗
PubMed2003

Construction of a gamete-enriched gene pool and RNAi-mediated functional analysis in Dictyostelium discoideum.

Macrocysts in Dictyostelium discoideum possess prototypic features of sexual reproduction and are useful for understanding the basic mechanisms of the reproductive process. Here, we randomly analyzed 1,071 gamete cDNAs, and then constructed a gamete-specific subtraction library, FC-IC. Nucleotide sequences of all 903 FC-IC clones were determined and clustered into 272 independent genes. Expression analysis based on real-time RT-PCR revealed 67 gamete-enriched genes, among which those involved in 'signal transduction' and 'multicellular organization' are prevalent. One of them, FC-IC0003, appeared also to be mating-type specific, and was named gmsA. RNAi-mediated silencing as well as disruption of gmsA reduced the cellular competency for sexual cell fusion, indicating the involvement of this gene in the sexual development of D. discoideum.

Amino Acid Sequence↗