this ppt gives a brief insight into the application of molecular probes with a special mention to agriculture.

1. APPLICATION OF MOLECULAR
PROBES
PRESENTED BY
AYUSH JAIN
PALB 7286

2. CONTENTS
Molecular Probes In Evolutionary Studies
Molecular Probes In Linkage and Chromosomal Mapping
Molecular Probes in Molecular Cytogenetics
Molecular Probes in DNA Fingerprinting.
Conclusion
Bibliography
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3. Molecular
Probes In
Evolutionary
Studies
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4. • Genomes has evolved by processes like
duplication and accumulation of useful
mutations into a common ancestral
sequences.
• This knowledge can be used to find out
evolutionary relationship between the
two organisms.
• As alterations has taken place both in
expressed and unexpressed regions in
genome RFLP gives fragments of
different length.
• RFLP coupled with DNA probe (a
common sequence from Ancestor) can be
used to find out the divergence and
relativeness among the compared
organisms.
Courtesy: C. T. Federici á D. Q. Fang R. W. Scora á M. L. Roose
Phylogenetic relationships within the genus Citrus (Rutaceae) and related genera as revealed by RFLP
and RAPD analysis
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5. Molecular Probes
In Linkage and
Chromosomal
Mapping
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6. • Linkage can define the genetic
distances between polymorphic
traits which may be recognized as
differences in appearance of
enzyme activities, restriction
fragment lengths or nucleotide
sequences at an allelic locus.
• Low number of morphological
markers are available to the plant
breeder for crop improvement
programs and the expression these
morphological markers is affected
by environmental conditions
which is not the case with
molecular markers.
• It has application in identification
of genetic disorders like sickle cell
anaemia, cystic fibrosis etc. and
also in MAS Breeding.
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7. Marker Assisted Selection Breeding
• One of the major
Application of molecular
mapping is MAS Breeding.
• Molecular markers are
specially advantageous for
agronomic traits that are
otherwise difficult to tag
such as resistance to
pathogens, insects and
nematodes, tolerance to
abiotic stresses, quality
parameters and
quantitative traits.
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Characters Examples
Rice
Resistance to blast caused by
Pyricularia oryzae
Pi-2(t) gene located 2.8 cM from RG64
on chromosome 6
Pi-4(t) gene located 15.3 cM from RG
869 on chromosome 12
Pi-10t gene tagged with RAPD
markers RRF6 and RRH18 on
chromosome 5.
Resistance gene Xa21 to bacterial
blight caused by Xanthomonas oryzae
Located 5.3 cM away from RAPD
marker RAPD818, RAPD248 and
RG103
Co-segregated xa5 with RFLP markers
RZ390, RG556, RG207 on
chromosome 5.
Brassica
Resistance against
Leptosphaeria maculans
Resistance against Albugo
RFLP markers on linkage group 6 in
Brassica napus
RFLP markers on linkage candida in B.
napus group 9

8. Molecular Probes
in Cytogenetics
• Isolation of genes
• In-situ Hybridization
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9. Isolation of Genes
• Specific Molecular Probes Can be Used For
Isolation of Specific Genes.
• Probes if Used from same Species are
Called Homologous Probes and From other
Species are called Heterologous Probes.
• Heterologous Probes are found Effective in
Identifying Genes Cloned during colony
Hybridization.
• These Probes are used with c-DNA Library
and not with Genomic Library as it can
Harbour Unrelated or Pseudogenes.
• Example: CHS (Chalcone Synthase gene
from Antirrhinum majus and Petunia
hybrida were isolated using c-DNA probe
and was used to isolate CHS gene from
Barley.
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10. In-Situ Hybridization
It is a Technique which permits detection of DNA and RNA sequences in Cell Smears, Tissue
Sections and Metaphase Chromosome spreads.
It is based on the Formation of Double Stranded hybrid molecules between Target sequence
and Complimentary single stranded Labelled probe.
Telomeres have been Identified in Human and other Eukaryotes using Telomeric sequence
as a Molecular probe showing that telomeres of all carry the same sequence.
This method is particularly useful if Target sequences are distributed in a non-random way
in tissues for visualization of heterogeneity and study of cell differentiation.
Used for rapid screening of small numbers of cultured cells for expression of Oncogenic m-RNA.
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11. Molecular Probes
in DNA
Fingerprinting.
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Invented by Sir Alec Jeffreys in
1985.

12. • It is also known as Genetic fingerprinting
or DNA profiling.
• DNA profiling, based on typing individual
highly variable minisatellites called
VNTR’s (Variable Number of Tandem
Repeats) in the human genome.
• VNTR’s can contain anywhere from 20-
100 bp.
• A southern blot is performed and then
probed through a hybridization reaction
with a Radioactive version of VNTR in
question.
• DNA fingerprinting has a high success
rate and a very low false positive rate
making it an extremely popular form of
paternity and maternity verification.
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13. Uses of DNA Fingerprinting
Pedigree
analysis and
establishing
paternity.
Immigration
authorities.
Identification of
mutilated dead
bodies.
Social security
record
identification.
In
characterization
of cell cultures.
In animal
breeding
programmes.
In plant
breeding
programmes.
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14. PRINCIPLES OF BIOTECHNOLOGY (PBT 501) January 11, 2018 14
In
demographic
studies.
Twin zygosity
determination
Tissue culture
cell line
identification
Mopping fine
grained
sequence
variation in
mini
satellites.

15. CONCLUSION
• Since Molecular probes assays are most sensitive
than conventional diagnostic methods, their use
has become today‘s most sophisticated and
sensitive technology for a variety of uses involving
biological systems both in basic and applied
studies.
• They give new dimensions to concerted efforts of
breeding and marker-aided selection that can
reduce the time span of developing new and better
varieties
• This ideal technology would offer absolute
specificity, modularity, minimal size, deliverability
(access to all cell types) and physiological
neutrality (noncytotoxic, biochemically)
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16. BIBLIOGRAPHY
• Anderson J A, Sorrells M E and Tanksley S D (1993), “RFLP Analysis of Genomic
Regions Associated With Resistance to Preharvest Sprouting in Wheat”, Crop Sci.,
Vol. 33, pp. 453-459.
• Deshpande A D, Ramakrishna W, Mulay G P, Gupta V S and Ranjekar P K (1998),
“Evolutionary and Polymorphic Organization of the Knotted-1 homeobox in Cereals”,
Theor Appl Genet., Vol. 97, pp. 135-140
• Fukuchi A, Kikuchi F and Hirochika H (1993), “DNA fIngerprinting of Cultivated
Rice With Rice Retrotransposon Probes”, Jpn. J Genet., Vol. 68, pp. 195-204.
• Madan Mohan, Suresh Nair, A. Bhagwat, T. G. Krishna, Masahiro Yano ,C.R. Bhatia,
Takuji Sasaki “Genome mapping, molecular markers and marker-assisted selection in
crop plants”, Mol. Breed., April 1997, Volume 3, Issue 2, pp 87–103
• K Vasavirama “MOLECULAR PROBES AND THEIR APPLICATIONS”, Review
Article, Int. J. LifeSc. Bt & Pharm. Res. 2013, Vol. 2, No. 2, April 2013
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17. A Tribute to
Molecular
Biologist all time
on his 96th
Birthday
• He Deciphered the Genetic Code
• 1968 Nobel Prize for Physiology
or Medicine.
• Dr. Har Gobind Khorana
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