Class 4 PDF-2 - Denis Maxwell PDF

Title	Class 4 PDF-2 - Denis Maxwell
Author	Wesley Tran
Course	Biology for Science II
Institution	The University of Western Ontario
Pages	6
File Size	414.9 KB
File Type	PDF
Total Downloads	16
Total Views	133

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Summary

Denis Maxwell...

Description

Class 4: Molecular homology

How does one prove homology?

catccggacgaggaggacgtgg aggcggcggagagcagggagca ccgccg gcgaaac aacgca gagaagg gcaaga gacgccg gctgcgggagttcgtggatgca gctta

GlsA

Volvox

catccggacgaggaggacgtgg aggcggcggagagcagggagca ccgccg gcgaaac aacgca gagaagg gcaaga gacgccg gctgcgggagttcgtggatgca gctta

GlsA

Chlamydomonas

1

glsA gene in Volvox vs Chlamy

Chlamydomonas Ancestral glsA

glsA

unknown function

glsA A sym m Volvox div etric isio ce n ll

2

Sequence alignment to detect similarity

Chlamy Volvox

Chlamy Volvox

Sequence alignment to detect similarity • Computer algorithm

3

Sequence alignment to detect similarity • National Center for Biotechnology Information (NCBI) – Repository of all genome, gene & protein data

BLAST • Basic Local Alignment search tool

BLAST

Database (DNA, RNA, Protein)

Query sequence

Output database sequences that align with your sequence

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Top BLAST hits against Chlamy GlsA

Top BLAST hits against Chlamy GlsA

5

Establishing homology through probability • The higher the similarity between two sequences the lower the probability that they originated independently of each other and became similar just by chance. • E-value (BLAST statistic) – Chance that two sequences have the score simply by chance. – E...