Sequence Alignment
Sequence
Alignment
What is Sequence Alignment?
What is Sequence Alignment?
• Quite simply, the comparison of two or more DNA or protein sequences to each other.
• The purpose of alignment is to highlight
similarity between the sequences.
Why Do We Use Alignment?
Why Do We Use Alignment?
Fundamental assumption of sequence alignment:
• Sequences that are similar share a common ancestral sequence.
• Due to common ancestry, similar sequences have similar functionality.
• Sequences that share a common ancestor are said to be homologous.
Alignment can be easy or difficult Alignment can be easy or difficult
GCGGCCCA TCAGGTAGTT GGTGG GCGGCCCA TCAGGTAGTT GGTGG
GCGTTCCA TCAGCTGGTT GGTGG Easy GCGTCCCA TCAGCTAGTT GGTGG
GCGGCGCA TTAGCTAGTT GGTGA ******** ********** *****
TTGACATG CCGGGG---A AACCG TTGACATG CCGGTG--GT AAGCC
TTGACATG -CTAGG---A ACGCG Difficult due to insertions or deletions(indels)
TTGACATG -CTAGGGAAC ACGCG TTGACATC -CTCTG---A ACGCG
******** ?????????? *****
