Applications of molecular
techniques used in research
Batten Disease
Neuronal ceroid lipofuscinosis (NCL)
 Neurodegenerative lysosomal storage disorder
 At least 13 distinct human NCL genes known, all causing the same clinical
features of visual failure, seizures and progressive motor and cognitive
decline
 Naturally occurring animal models, including sheep, whose disease closely
matches the human
 No effective therapies
Batten Animal Research Network
Gene therapy
virus
Gene therapy
Disabled
virus
In vitro (in the lab)
In vivo (in the animal)
+
Corrective NCL
gene
Corrective NCL gene
packaged into virus
Vector inserts gene
 Using DNA that encodes a
functional, therapeutic NCL gene
to replace the mutated or
missing NCL gene
 Injection of the viral vector
containing the corrective NCL
gene into the brain of affected
sheep
Corrective
protein produced
Nucleus
Target brain cell
 Gene expression of the missing
gene and production of the
corrective protein
Battens Disease Research by Professor David Palmer
Transposons
(Evolutions “dead-mans” switch)
• Mobile genetic elements = Transposons
• Present in all organisms (yes - even Humans!!)
–
–
–
–
The larger the genome the higher % of TEs present
Humans = 50% TEs
Grapes = 45% TEs
Wheat = >75% TEs
Transposons – things they
do…..
• New insertions at new
locations
– Can destroy gene function
– Can change gene activity
– Can shuffle exons making
new genes with new
functions
• Existing and new insertions
can influence the function
of DNA flanking genome
insertion sites = one
important aspect of
epigenetics
Transposons – Parasites or an
evolutionary force for good?
•
Both! - They are parasites that
have been harnessed by
evolution
•
Most TEs contain regulatory
elements that respond to and
are activated when the host
plant is exposed to stress
•
It appears that retention of TEs is
an evolutionary adaptation to
rapid environmental change
– Activation under stress conditions
(release of the dead-mans switch)
can introduce massive amounts of
new genetic diversity within a
single generation
Cyclodia
methylation
Cyclodia
Transposon
Transposons & Functional
genomics
Develop somatic embryo cultures
Recover plants
Regenerate plants
Activate TEs using stress
Genotype to identify
new element insertions
and their location
Screen data for mutation in key genes
•
Identify genes + mutation
•
Identify individuals in the population
•
Assess the phenotypic impact of the mutation
•
Determine the function of the gene
Screen population for new phenotypes
•
Identify new plants with desirable traits
•
Interrogate database to find out what
new mutations are present
•
Identify genes mutated
•
Use information to ascertain gene
function and /or use as markers for
rapid breeding
Transposons –
Research by Dr Chris Winefield
Powelliphanta augusta
 New species of endemic giant landsnail
 Single population located within mine footprint
 Snail collected for translocation and captive management
 No idea of their feeding requirements
Walker et al.—New Powelliphanta species from Mt Augustus
 Snails are nocturnal and difficult to observe feeding
173
Molecular diet analysis
Using snail faeces
 DNA barcoding on snail feces
(non invasive method)
 Detection of at least 18
species of earthworms eaten
by the snails
 Information useful for the
selection of new
translocation sites and to
feed the snails in captivity
 Discovery of new species of
earthworms never found
before
Snail speciation –
Research by Dr Stephane Boyer