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CONSERVATION OF PLANT SPECIES IN DNA BANKS
C Kameswara
Rao
Foundation
for Biotechnology Awareness and Education,
DNA banks or Gene
banks are the ultimate facility for the ex situ conservation of
genetic material to be sourced for a) genomic studies, b)
to compile genomic libraries,
and c) to isolate desired genes at will, for genetic engineering.
However, currently they are not useful in regenerating whole plants, unlike the
other forms of germplasm banking.
Any part of a plant yields DNA. Plant material is dried using silica gel and
stored at -800 C to extract DNA from it. When fresh supplies not available, DNA can be
obtained from dried plant material stored in botanical research institutions
that house pressed and dried plant specimens called ‘herbarium’. Though some fraction of the DNA from dried
plants may be degraded, it would yield quality DNA in sufficient
quantities.
DNA samples in the banks pass through extensive
extraction procedures, minimizing cleaning process before using the
sample. However, the quality and
concentration of DNA in a sample vary with species and so concentration
procedures may be needed. Even small quantities
of DNA are adequate as they can be amplified a million fold using the technique
of ‘polymerase chain reaction’
(PCR) that yields much larger quantities of DNA from minute quantities.
Samples in DNA banks are so well purified that they
are stable at ambient temperatures for days in transit. While within the bank
under controlled conditions, they are stable almost indefinitely. Ten-year old
DNA samples were near perfect.
DNA banking is more economical than other forms of germplasm banking, as it occupies far lesser space, almost
indefinitely viable and a small sample can be shared by many researchers
through PCR amplification, without the need for repetitive extractions.
DNA BANKS
The following are some important examples among
several DNA banks established in different parts of the world, which are
networked for collaborative activity:
DNA Bank of the Royal Botanic Gardens, Kew
The DNA Bank at the Jodrell
Laboratory, Royal Botanic Gardens, Kew, England, contains over 22,000 samples of plant genomic
DNA, all stored at -80°C. Information on the stored DNA is databased
providing the names of the species, collectors, localities, etc. Each sample
has a reference voucher of a herbarium specimen. This database is linked to the Plant DNA
C-values Database and the Database of the International
Plant Names Index, which is quite useful.
DNA samples are provided to the collaborators all over
world but can also be purchased by the others on a Material Transfer
Agreement.
Plant DNA Bank in Korea (PDBK)
The PDBK website provides genomic lists of
stored DNA and tissue samples, and their voucher information (label, specimen,
and photo) held in PDBK and Korea University Herbarium (KUS), both located in
the Graduate School of Biotechnology, Korea University, Seoul, Korea.
The Australian Plant DNA Bank (APDB)
The APDB located at Southern Cross University's Centre for Plant Conservation
Genetics at Lismore, is a
comprehensive collection of DNA from both Australian native and important crop
plant species. It also contains DNA of transgenic organisms developed through genetic engineering. The APDB has invested heavily in
advanced DNA storage facilities to ensure long term preservation of extracted
DNA.
Missouri
Botanical Garden’s DNA Bank (MBGDB)
Although the MBG describes its activity as
‘DNA Banking’, there is no evidence on its website that MBG banks extracted DNA
samples. It is a collection of samples
of plant material stored at -20°C, suitable for DNA extraction. Voucher specimens for these samples are
deposited at the MBG or other institutions.
The material is provided to researchers against an agreement for
molecular studies but not for commercial purposes such as bioprospecting, or screening for genes of interest in agricultural
research.
DNA
Bank Brazilian Flora Species
The Bank at the
The Leslie Hill Molecular Systematics Laboratory at Kirstenbosch,
in collaboration with the Royal Botanic Gardens,
-80ºC. Each accession has a corresponding herbarium
voucher.
The NIAS,
NATIONAL BUREAU OF PLANT GENETIC RESOURCES (NBPGR)
The NBPGR,
GENE
BANKS IN THE PRIVATE SECTOR
The private sector organizations, mostly
multinational corporations, engaged in genetic engineering of crop plants have
extensive collections of crop plant DNA.
Their extensive genomic libraries are an important source of useful
genes for crop improvement. However,
this valuable material and information are not generally accessible to the
public sector.
RESPONSIBILITIES
OF DNA BANKS
The DNA banks have serious responsibilities in order
to fulfill their mandates. The more
important of them are:
a) Ensuring the authenticity of the scientific identity,
source and geneology of
the source species;
b) Adopting state of the art procedures of collection,
recording, processing and preservation of DNA;
c) Maintaining quality DNA in adequate quantities;
d) Ensuring responsible use of the material supplied to
others, assuring equitable benefit sharing by all parties;
e) Networking internationally, with other DNA banks,
facilitating exchange of knowledge and material and to prevent duplication of
efforts; and
f)
Updating websites
frequently and fulfilling the promises made.
September 21, 2008
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CONSERVATION OF PLANT GENETIC RESOURCES
CONSERVATION OF PLANT SPECIES IN SEED BANKS
CONSERVATION OF PLANT SPECIES IN GERMPLASM BANKS