Download HGT

Hunting down the Alien (gene)!
Lavanya Rishishwar
School of Biology
Primary Objectives
• HGT
o An understanding of HGT
o Methods of analyzing HGTs
o Finding candidate HGT regions in a genome
• PAI
o An understanding of PAI
o Searching for PAIs using PAIdb and PAI Finder
Part - I
HORIZONTAL GENE TRANSFER
(HGT)
Introduction
• HGT, also known as Lateral
Gene Transfer (LGT), is the
transfer of genetic material
between organisms other
than through
vertical
gene that studies vertical transfer of
What
is the science
genes?
transfer
• They are “alien” regions in
the genome (chromosome
or plasmids)
Mechanisms
Why they are interesting?
• Bacteria can steal a beneficial gene that arose in
another cell instead of waiting for it to evolve, e.g.
o Antibiotic Resistance
o Pathogenecity
• If a bacterium loses a gene, it can reacquire it
through HGT
Why they are interesting?
• There is a limit to which it can acquire these genes:
Bigger the genome, slower the replication
• LGT may not always be functional:
o
o
o
o
o
o
Non-coding LGT
Duplicate copy
Requires other genes
Might disrupt a gene at the insertion site
Might interfere with existing function
Acquiring a selfish gene – e.g. a viral insertion
How can we detect them?
Part - II
PATHOGENICITY ISLANDS
Introduction
HGT!
• They are mobile genetic elements that confer
virulence to a pathogen
• Could be located on the chromosome or the plasmid
PAIdb and PAI Finder
• https://www.gem.re.kr/paidb/
Part - III
UTILITY
An example