so we can conclude that xenobiology can give various answers of life and also can help to discover various biochemical reaction as well as can increas economy of one country

1. ROLL NO.17
SEM-4
GOVT. SCIENCE COLLEGE

2. XENOBIOLOGY
• Xeno- strange or guest
• Biology – study of life
• So xenobiology is a study of strange form of life
What is
xenobiology?

3. DEFINITION
• Xenobiology (XB) is a subfield of synthetic biology, the study of
synthesizing and manipulating biological devices and systems.
Xenobiology derives from the term xenos (Greek)and means
"stranger or guest". So XB describes a form of biology that is not
(yet) familiar to science and is not found in nature

4. INTRODUCT
ION

5. The genetic code of all living
organisms does not know
more than eight nucleoside
triphosphates, four in RNA
and four in DNA
Synthetic biologists have
now altered these
canonical nucleotides to
the effect that natural
biological organisms and
systems cannot read and
interpret them any more
Normal genome We know
four
alphabets!
Well then
also u cannot
read me!!
Lol!!
Synthetic genome

6. • Experiments replacing or enlarging the genetic alphabet of DNA with
unnatural base pairs led for example to a genetic code that instead of four
bases ATGC had six bases ATGCPZ
• 60 candidate bases (that means 3,600 base pairs) were tested for possible
incorporation in the DNA
Example ,At least on one occasion a modified variant of the HIV-reverse
transcriptase was found to be able to PCR-amplify an oligonucleotide
containing a third type base pair.
Only two amino acids were substituted in the natural polymerase optimized
for the four standard nucleotides to create one that supports repeated PCR
cycles for the amplification of an expanded genetic system.

7. XNA

8. Backbone of dna contain five carbon containing ring that is pentose
while the Xna backbone contain as threose, glycol, hexitol etc.
Such as-
TNA (THEROSE NUCLIC ACID)
GNA (GLYCO NUCLIC ACID)
HNA (hexitol NUCLIC ACID)

9. • Tna- is an artificial genetic polymer invented by Albert Eschenmoser. TNA has
a backbone structure composed of repeating threose sugars linked together
by phosphodiester bonds. Like DNA and RNA, TNA can store genetic
information in strings of nucleotide sequences
• Gna- is an artificial genetic polymer compose of repeating units of glycol
linked with phosphodiester bonds. Like dna and rna , gna can also store
genetic information in a string of nucleotide sequence
• HNA- hexitol nucleic acid an artificial polymer compose of repenting units of 6
carbon containing monosaccharide linked together by phosphodiester bond

11. • The authors picked five in total, all with features that were
distinct from the normal sugars, like a double bond between
carbon atoms, a fluorine replacing an oxygen, and a double-ring
structure. Collectively, they termed these DNA/RNA substitutes
XNAs.
• Although the genetic information is still stored in the four
canonical base pairs, natural DNA polymerases cannot read and
duplicate this information. In other words the genetic
information stored in XNA is “invisible” and therefore useless to
natural DNA-based organisms
• Using their lab-made XNAs as building blocks, the team were
able to create synthetic enzymes, which they have named
‘XNAzymes’, that could cut up and stitch together small chunks of
genetic material, just like naturally occurring enzymes

12. Example ,At least on one occasion a modified variant of the HIV-
reverse transcriptase was found to be able to PCR-amplify an
oligonucleotide containing a third type base pair.
Only two amino acids were substituted in the natural polymerase
optimized for the four standard nucleotides to create one that
supports repeated PCR cycles for the amplification of an expanded
genetic system.

13. APPLICATIO
N

14. MEDICINES
Medicine, too, could benefit from
XNAs, Romesberg says. Doctors
already prescribe biological
products such as enzymes and
antibodies to treat certain
diseases, but these drugs break
down quickly in the stomach and
the blood stream. Because XNAs
are somewhat foreign, they're
not broken down as quickly in the
body, as it has not evolved
enzymes to digest them.

15. main opportunities
Better
understanding of
the origin of life
More efficient
industrial
biotechnology
production systems
A solution to the
upcoming biosafety
challenges
Why was this basic
chemical make-up
evolutionarily successful
while others were not?
Industrial strains with a
fundamentally different
genetic code would
suddenly be immune to
natural phages or viruses.
genetic firewall

16. CONCLUS
ION

17. REFERENCE
• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2909387/
• https://books.google.co.in/books?id=nbuKezXzmZUC&pg=PA326&lpg=PA326&dq=ATGCPZ&source=bl&
ots=uxbh_alk0u&sig=INZc9fAjVu95dY_N8U4CpmpPrEE&hl=en&sa=X&ei=7iDXVKuzDcSMuATu94DQCw&
ved=0CCIQ6AEwAA#v=onepage&q=ATGCPZ&f=false
• http://www.dailymail.co.uk/sciencetech/article-2857172/Do-need-DNA-form-life-Breakthrough-
synthetic-enzymes-lead-manufacture-organisms.html
• http://www.popularmechanics.com/science/health/a7636/xna-synthetic-dna-that-can-evolve-
8210483/