• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.113-117
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• 1997

Simple sequence repeats (SSR) are widely dispersed throughout eukaryotic genomes, highly polymorphic, and easily typed using polymerase chain reaction (PCR). The objective of this study was to determine the polymorphism of different Chlamydomonas reinhartdtii strains and to determine the mode of inheritance of the SSR locus in Chlamydomonas. A genomic DNA library of C. reinhardtii was constructed and screened with a radiolabeled $(AC)_{11}$ probe for the selection of (CA/GT)n repeat clone. Selected clone was seqeuenced, and PCR primer set flanking (CA/GT)n sequence was constructed. PCR was used to specifically amplify the SSR locus from multiple isolates of C. reinhardtii. The locus was polymorphic in some of the C. reinhardtii isolates. However, the locus was amplified only 4 of 6 isolates of C. reinhardtii, not in other 2 isolates of C. reinhardtii, suggesting that this locus is not extensively conserved. A simple Mendelian inheritance pattern was found, which showed 2:2 segregation in the tetrads resulting from a cross between C. reinhardtii and C. smithii. Our results suggest that this simple sequence repeat DNA polymorphism will be useful for identity testing, population studies, linkage analysis, and genome mapping in Chlamydomonas.

• Parasites, Hosts and Diseases
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• v.56 no.2
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• pp.175-181
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• 2018

The giant roundworm Ascaris infects pigs and people worldwide and causes serious diseases. The taxonomic relationship between Ascaris suum and Ascaris lumbricoides is still unclear. The purpose of the present study was to investigate the genetic diversity and population genetic structure of 258 Ascaris specimens from humans and pigs from 6 sympatric regions in Ascaris-endemic regions of China using existing simple sequence repeat data. The microsatellite markers showed a high level of allelic richness and genetic diversity in the samples. Each of the populations demonstrated excess homozygosity (Ho0). According to a genetic differentiation index (Fst=0.0593), there was a high-level of gene flow in the Ascaris populations. A hierarchical analysis on molecular variance revealed remarkably high levels of variation within the populations. Moreover, a population structure analysis indicated that Ascaris populations fell into 3 main genetic clusters, interpreted as A. suum, A. lumbricoides, and a hybrid of the species. We speculated that humans can be infected with A. lumbricoides, A. suum, and the hybrid, but pigs were mainly infected with A. suum. This study provided new information on the genetic diversity and population structure of Ascaris from human and pigs in China, which can be used for designing Ascaris control strategies. It can also be beneficial to understand the introgression of host affiliation.

• Journal of Plant Biotechnology
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• v.7 no.1
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• pp.17-25
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• 2005

We have mined each of the five A. thaliana chromosomes for the presence of simple sequence repeats (SSRs) and developed custom perl scripts to examine their distribution and abundance in relation to genomic position, local G/C content and location within and around transcribed sequences. The distribution of repeats and G/C content with respect to genomic regions (exons, UTRs, introns, intergenic regions and proximity to expressed genes) are shown. SSRs show a non-random distribution across the genome and a strong association within and around transcribed sequences, while G/C density is associated specifically with the coding portions of transcribed sequences. SSR motif repeat number shows a high degree of variation for each SSR type and a high degree of motif sequence bias reflecting local genome sequence composition. PCR primers suitable for the amplification of identified SSRs have been designed where possible, and are available for further studies.

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.335.1-335
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• 1995

No Abstract, See Full Text

• Proceedings of the Plant Resources Society of Korea Conference
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• 1997.03b
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• pp.48-48
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• 1997

• Journal of Plant Biotechnology
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• v.5 no.4
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• pp.193-195
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• 2003

A major goal of agricultural biotechnology is the discovery of genes or genetic loci which are associated with characteristics beneficial to crop production. This knowledge of genetic loci may then be applied to improve crop breeding. Agriculturally important genes may also benefit crop production through transgenic technologies. Recent years have seen an application of high throughput technologies to agricultural biotechnology leading to the production of large amounts of genomic data. The challenge today is the effective structuring of this data to permit researchers to search, filter and importantly, make robust associations within a wide variety of datasets. At the Plant Biotechnology Centre, Primary Industries Research Victoria in Melbourne, Australia, we have developed a series of tools and computational pipelines to assist in the processing and structuring of genomic data to aid its application to agricultural biotechnology resear-ch. These tools include a sequence database, ASTRA, for the processing and annotation of expressed sequence tag data. Tools have also been developed for the discovery of simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) molecular markers from large sequence datasets. Application of these tools to Brassica research has assisted in the production of genetic and comparative physical maps as well as candidate gene discovery for a range of agronomically important traits.

• Korean journal of applied entomology
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• v.50 no.4
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• pp.325-333
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• 2011

This study focused on the green peach aphid, Myzus persicae, as an indicator pest in Chinese cabbage cultivation to develop a genetic marker. We hypothesized that M. persicae gene flow is related to climate change. Genetic variation was analyzed using five local populations collected at different altitudes (157 m, 296 m, 560 m, 756 m and 932 m above sea level) in Hoengseong, Pyeongchang, and Gangneung areas, plus a laboratory strain used as an outgroup. There were no differences in ecological characteristics among strains. Esterase isozyme pattern and inter-simple sequence repeat (ISSR) PCR results showed significantly different bands between laboratory and wild, local populations. However, there was no difference among local populations. Partial fragments of ribosomal RNA (rRNA) and mitochondrial cytochrome oxidase I (mtCO I) were amplified and their nucleotide sequence was analyzed. Single nucleotide polymorphisms (SNPs) were detected in internal transcribed spacer-2 (ITS-2) and mtCO I regions among the five local populations. These SNPs can be use to discriminate different populations of M. persicae to monitor gene flow.

• Molecules and Cells
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• v.27 no.2
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• pp.237-241
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• 2009

Pathogens Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm) contain a large number (> 12,000) of Simple Sequence Repeats (SSRs). To study the extent to which these features have contributed to the diversification of genes, we have conducted comparative studies with nineteen genomes of these bacteria. We found 210 genes with characteristic types of SSR variations. SSRs with nonamer repeat units were the most abundant, followed by hexamers and trimers. Amino acids with smaller and nonpolar R-groups are preferred to be encoded by the variant SSRs, perhaps due to their minimal impacts to protein functionality. A majority of these genes appears to code for surface or secreted proteins that may directly interact with the host factors during pathogenesis or other environmental factors. There also are others that encode diverse functions in the cytoplasm, and this protein variability may reflect an extensive involvement of phase variation in survival and adaptation of these pathogens.

• International Journal of Industrial Entomology and Biomaterials
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• v.41 no.2
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• pp.56-62
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• 2020

Mulberry (Morus spp. family: Moraceae) has prime importance in the sericulture industry, and its foliage is the only natural feed of the silkworm Bombyx mori L. Traditional classification methods using morphological traits were largely unsuccessful in assessing the diversity and relationships among different mulberry species because of environmental influences on the traits of interest. For these reasons, it is difficult to differentiate between the varieties and cultivars of Morus spp. In the present study, inter-simple sequence repeat (ISSR) markers were used to investigate the genetic diversity of 48 mulberry samples genotyped using nine ISSR primers. The ISSR markers exhibited polymorphisms (53.2%) among mulberry genotypes. Furthermore, similarity coefficient estimated for these ISSR markers was found to vary between 0.67 and 0.99 for the combined pooled data. The phenogram drawn using the UPGMA cluster method based on combined pooled data of the ISSR markers divided the 48 mulberry genotypes into seven major groups. No genetic association was found in the collection area, and there was a mixed pattern between the mulberry lines. The hybridization between different mulberry species is highly likely to be homogenized due to natural hybridization.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.10a
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• pp.75-75
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• 2003