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Reliability of ITS in Species Identification by Surachit Waengsothorn.

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Presentation on theme: "Reliability of ITS in Species Identification by Surachit Waengsothorn."— Presentation transcript:

1 Reliability of ITS in Species Identification by Surachit Waengsothorn

2 What’s ITS ITS stands for Internal Transcribed Spacer regions Where are they? These regions are located in ribosome.

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5 Ribosomal RNA 5S rRNS5.8s rRNA18s rRNS 120bp 160bp ~1900bp ITS1 ITS2

6 What’s ITS ITS stands for Internal Transcribed Spacer regions Where are they? These regions are located in ribosome. Why do I pick ITS? rRNA is highly conserved across texa while the ITS may be species-specific.

7 rRNA evolution rate use Small-subunit very slow distantly related organisms Mitocondrial more rapidly family level ITS fastest variation among species

8 Species In the past 30 years, over six concepts have been proposed. Species is a very simple word BUT its definition is not that easy. Three majors concepts: -The biological species concept - The phylogenetic species concept - The morphospeceis concept

9 The biological species concept proposed in 1942 by Ernst Mayr used by many zoologists defined “species” in Endangered Species Act Criterion: reproductive isolation (lack of gene flow) populations do not hybridize populations fail to produce fertile offspring Cons: can be applied to only living organisms difficult to keep tract on all populations

10 The phylogenetic species concept Criterion: monophyly Populations contain all the know descendants of a single common ancestor. Species are the smallest diagnosable monophyletic groups. The morphospeceis concept: used by paleontologists They define species on the basis of morphological differences among fossils.

11 All concepts share three things in common: 1) Species consist of interbreeding populations. 2) Species are a fundamental unit of evolution. 3) Species share a distinguishing characteristic.

12 Why is species identification so important? Species plays a major role in all conservation aspects. Species identification is a starting point of life science disciplines i.e. biology, ecology, forestry, biotechnology, etc. Species identification is daily used in many careers such as farmers, foresters, lawyers, gardeners, researchers, scientists, curators, ete.

13 Method Data collections: Lab work: - extract DNA from a sugar maple sample. - amplify ITS region using PCR technique. - perform fragment sequencing. 5s RNA 5.8s RNA18s RNA ITS1 primer:TCCGTAGGTGAACCTGCGG ITS4 primer: TCCTCCGCTTATTGATATGC

14 Method (cont.) Office work: - search around the cool web (NCBI home page) and collect ITS data of maples. - use GCG to perform pileup, pretty - consensus, tofasta. - put fasta file in clastalW, and get the tree from Treeview Data collections:

15 Results 15 species of maples (genus Acer) 3 sample per species except sugar maple has only 2 samples + 1 sample of mine. Pretty -consensus

16 Results 15 species of maples (genus Acer) 3 sample per species except sugar maple has only 2 samples + 1 sample of mine. Pretty -consensus Clustal W

17 Treeview

18 Data Interpretation Recommendations Unknown sample(s) is(are) recommended to compare with at least three sequences of a known species, and several species in the same genus or different genus in the same family. ITS is a powerful tool to discriminate species. 42 of 45 sequences (>93%) support the hypothesis.


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