Download Launch of New Mate Select Tool

Launch of New Mate Select Tool:
EBVs
(Estimated Breeding Values)
‘Single gene mutations’ (normal
DNA tests)
gene A
‘Affected’
‘Clear’
Both copies of the gene are
abnormal, and so an incorrect
version of the protein is produced
(or is not produced at all). The
protein therefore either does not
function, or does so less well than
the normal copy, leading to disease.
Both copies of the gene are
normal variants, and so the
protein is produced and
functions as it should.
‘Carrier’
One normal variant and one abnormal
variant. Half the protein produced functions
normally. This is often enough and so no
disease is apparent. However, the abnormal
copy may be inherited by offspring.
But what about complex conditions?
• There could be several/many genes involved
(multi-variant)
• There could be “outside” influences
(environmental factors)
• Currently only assessing through “Schemes” –
the best option up to now, but harder to
predict risk
Most traits (and diseases) are
affected by multiple genes
(often hundreds), each gene
adding a small amount of
increased or decreased risk.
Each gene can have the 3
combinations of normal and
abnormal copies as before
Genetic variation
A
B
C
D
So if we look at a sample of dogs we
can see the number of different
combinations. This produces genetic
variation in the risk of disease. Thus
we get a continuous spectrum of
genetic risk, which is normally
distributed (Bell curve – few at
either end, more in the middle)
E
gene A
gene B
gene C
gene D
gene E
Genetic risk
We have the genetic variation in risk,
which is fixed at conception for 5 dogs.
But this risk is overlaid or modified by
environmental influences on hip score.
The rank on hip score is not the same as
rank on genetic risk, but only the genes
are passed onto the next
generation…
So, going from genes to disease
(or in this case, hip score)
Dougal Pluto Snoopy Muttley Gnasher
in utero environment
neo natal
environment
feed intake
diet
exercise
0
Pluto
Dougal
Gnasher
Muttley
Snoopy
106
? ? ? ? ?
Currently all we have to select on is the
phenotype – the hip score. But we have
already seen that this is not necessarily the
most accurate indicator of the genetic risk.
0
Pluto
Dougal
Gnasher
Muttley
Snoopy
106
Overview of EBVs
• EBVs have been used for many years in other species, and are “tried and
tested”
• In principle, you can make an EBV for anything that is measurable:
complex conditions, size/shape, yields (i.e. milk in cows), etc.
• 15 breeds with hip or hip and elbow: Akita, BMD, Bearded Collie, Border
Collie, Eng. Setter, Flat Coated Retriever, Gordon Setter, GSD, Golden
Retriever, Labrador, Newfoundland, Siberian Husky, Rottweiler, Rhodesian
Ridgeback, Tibetan Terrier
SNEAK PREVIEW!
EBVs
EBV stands for: Estimated Breeding
Values
They estimate the genetic risk of
complex diseases
EBVs are a more efficient way to
estimate risk, and breed away from
undesirable traits more quickly than by
individual dog results (phenotypic)
alone
EBVs use Health Scheme data for
calculation
Benefits of EBVs to Dog Health and
Breeders
• More accurate assessment of a dog’s genetic risk
• The lower the EBV, the better but there isn’t a
need to seek out the very lowest EBV – selecting
any animal with a lower risk EBV than average
will apply selective pressure to improve hip
scores faster than an individual hip score alone
• More flexibility in choosing mates as the EBV
measures genetic (heritable) risk, as opposed to
the individual score, which measures the risk for
that dog
FAQs
• Will a dog’s EBV ever change?
– Yes. The genes are fixed, but the EBV estimate can change over time as
more data becomes available. At birth, a puppy’s EBV is based on hip
scores of parents and relatives, but as progeny are produced and
tested, the EBV will increase in accuracy and may change. In addition,
as the breed average is set to 0 on the risk bar, this will shift as the
breed average improves.
• End of hip/elbow scoring?
– EBVs are a more effective way of using the information we already
have: no more hip scores = no more EBVs
– The best way to ensure good EBVs is to continue to score and use EBVs
as the indicator of genetic risk in breeding plans
– An individual dog’s hip score is still the only way to indicate the degree
(or not) of dysplasia in that particular dog
– Just as in DNA tests vs. the Eye Scheme, EBVs are an additional tool,
not a replacement.
Key Messages
• People should aim to select a
puppy with a lower risk EBV than
average (the average being 0)
• The EBVs have been prepared in 5
breeds for hips and elbows and
10 for hips only
• EBVs need pedigree to work so
this can only be done on KC
registered dogs.
• One third of the total number of
dogs registered with the KC
between 2000 and 2010 will now
have hip EBVs, based on the dogs
within the breeds that have been
used to date.
• EBVs are only available to those
who have breeds who have up
until now been tested.
• EBVs will only be
valuable/useable with continued
testing
• It is estimated that another 10-20
breeds could be added for hip
scores and this will continue to
increase as more breeds make
use of health screening increases.
• The future: Which other
conditions can EBVs be generated
for and which other breeds will
benefit in the future?
THANK YOU!