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Molecular identification
Our customer service:
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Molecular species identification
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Molecular determination of organisms causing diseases (pathogens)
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Depending on the problem we analyse marker gene sequences (e.g. 16S rDNA or 18S rDNA, SSU rDNA genes) or highly variable DNA regions (e.g. ITS regions = internal transcribed spacer regions)
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DNA sequence alignment using sequences published in public database (GenBank)
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Reconstruction of evolutionary relationships or genetic relatedness to known organisms
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Phylogenetic studies and reconstruction of the evolution
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If desired we can classify the sequences using a molecular species concept
Our customers provide:
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Organic samples or sequences (GenBank, FASTA, …)
What is a "molecular species identification"?
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This is a simple approach to explain why we can use DNA for investigating
the relatedness of organisms.
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All organisms contain DNA (desoxy-ribonucleic acid) which consists out
of coding regions (genes) and non-coding regions (spacers and other regions).
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Genes contain information on the structure of RNAs (ribonucleic acid) and most
RNAs are translated into protein sequences by the cells. Proteins give organisms
functionality and structure. Therefore, organisms are quite sensible with respect
to changes in their fundamental units, their genes. This is the reason why genes are
quite stable or in other words: changes in gene structure can influence the fitness
of the cell in a disadvantageous way.
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Certain genes (e.g. the SSU rRNA genes) occure in all organisms and, therefore, can
be used to compare these organisms on a molecular level. One can even reconstruct the
evolution of organisms using comparative gene analysis.
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In other regions of genomes, e.g. spacer regions, changes can be quite dramatic
without influencing the fitness of the organisms. These regions can be used to
compare closely related organisms, e.g. populations of a species, where most of the
gene sequences are identical or too similar to yield a sufficient discrimination.
Keywords: DNA extraction, cloning, PCR, sequencing, 18S rRNA gene, 16S rRNA gene, rbcL gene, ITS region, gene, spacer region, sequencing, alignment, cladistic analyses, phylogeny, phylogenetic approach, tree visualisation
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Methods