1. Presented by:-
Jadhao Kundansingh R.
09ABT/11
Department of Agril-biotechnology,
Orissa University of Agriculture & Technology,
BBSR.
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4. Identification and access to allelic variation that
affects the plant phenotype is of the utmost
importance for the utilization of genetic resources,
such as in plant variety development.
Considering the huge numbers of accessions that
are held collectively by gene banks, genetic
resources collections are deemed to harbour a
wealth of undisclosed allelic variants.
The challenge is how to unlock this variation.
Allele mining is a research field aimed at
identifying allelic variation of relevant traits within
genetic resources collections.
5. It helps in tracing the evolution of alleles
Identification of new haplotypes and
development of allele-specific markers for use
in marker-assisted selection
This capability will be important for giving rice
breeders direct access to key alleles conferring
(1) resistance to biotic stresses, (2) tolerance
of abiotic stresses, (3) greater nutrient use
efficiency, (4) enhanced yield, and (5) improved
quality, including human nutrition
6. It can also provide insight into molecular basis
of novel trait variations and identify the
nucleotide sequence changes associated with
superior alleles. In addition, the rate of
evolution of alleles
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11. The TILLING Method. Seeds are treated with a chemical mutagen to induce
genetic variation, and then planted. Theresulting M1 population of plants is
chimeric for mutations. Therefore, one seed from each M1 is planted to create
the M2 population.
M2 DNA is extracted from leaf tissue DNA samples are pooled to increase
throughput and PCR amplified with dye-labeled PCR primers specific to a
target gene of interest. PCR products are denatured and allowed to reanneal to
form heteroduplexes. Heteroduplex DNA is then cleaved by Cel I and analyzed
12. Illustration of a Cel I cleavage reaction. PCR primers that have been end-labeled with
two different color dyes (red and green arrows) are used to amplify a targeted region
of the genome in a pool of DNA consisting of multiple individuals. After PCR, DNA
fragments are denatured and allowed to reanneal to form homoduplexes and
heteroduplexes. Cel I is added to the reaction and cleaves DNA 3’ of the mismatch.
The cleavage reaction is concentrated, denatured and separated electrophoretically
on a LI-COR DNA analyzer.
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14. DNA from many (eight) plants are pooled, The amplified products are denaturated by
heating and cooling slowly for randomly re-annealing and forming homo- and heteroduplexes,
double-stranded products are digested by CELI endonuclease, ---Gel Electrophoresis
