Metagenomic Essay

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Presence of white-clawed crayfish until 1990
Presence of narrow crayfish in the UK from x-x

Species-specific primers The first step in the design of species–specific primers is to choose the suitable gene for the organism of interest, and then collect the reference sequence from GenBank and align them in corresponding alignment software. A conservation region among sentences is founded and primers are designed incorporating conservation region with few mismatches in forward and reverse primers. These mismatches are crucial to discriminate between similar species. Afterward, primers are tested on target organism tissue in the laboratory environment and in situ.

Metagenomics and metabarcoding
The term metagenomics refers to “direct
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The important part which distinguishes nuclear and mt and plastid DNA is the absence of recombination, which occurs in the nuclear genome during the meiosis. Thus, the differences present in mtDNA or plastidDNA are the product of mutation, which makes genes from those organelles a powerful tool in differentiation between species. Nevertheless, some studies support the idea of recombination in mtDNA (Chen, 2013; Leducq et al.,2017). Additionally, mtDNA is more suitable for species detection due to high copy number in cells although some of this DNA copies are not identical (heteroplasmy), (Wallace and Chalkia, 2013).
The common gene for sequencing bacterial communities is 16S rRNA, a mitochondrial gene, although other genes such as cpn60 (chaperonin) can be used for bacterial sequencing and for phylogenetic studies (Hill et al, 2004; Janda and Abott, 2007; Mignard and Flandrois, 2006). Mitochondrial genes cytb (cytochrome b gene) and COI (cytochrome oxydase I), also mitochondrial genes, are used for a wide range of vertebrates and invertebrates. Mitochondrial genes are most suitable for identification of taxonomic group end evolutionary relationship due to high mutation events (http://www2.le.ac.uk), and the additional gene for eukaryotes identifications is mitochondrial 18S rRNA gene. Plastid genes rbcl (ribulose1,5-bisphosphate carboxylase gene) and matk (maturase K gene) which have similarities with mitochondrial genes such are their own DNA and
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