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Hello, my name is Daniel Gianola.
I'm a Professor
at the University of Wisconsin-Madison,
and I'm also
a Hans Fischer Senior Fellow
at the Technical University of Munich,
in Germany.
And today, I will be talking
about "A Brief History
of some Statistical Developments
in Animal Breeding".
I will cover about
100 years of developments.
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So the first question is,
"What is animal breeding?"
By this, we mean the genetic improvement
of farm animals mostly,
animals that serve and enrich mankind.
The question is,
"What individual is best?"
For that, we need to define
some "merit function",
which typically will depend
on several traits.
The same happens in plant breeding.
For example, some variety of wheat
will depend not only on grain yield
but also on dry matter content,
resistance to disease,
resistance to wind,
and some other attributes.
In order to decide what animals
or individuals are best,
we take measurements,
such as milk production in dairy cows,
growth rates in animals.
We have genealogies or pedigrees
that trace animals
according to lines of descent.
More recently, molecular markers
that we know as SNPs, S-N-Ps,
single nucleotide polymorphisms.
In the future,
full DNA sequences,
and also post-genomic data,
such as gene expression,
level of methylation,
which are now available
for experimental purposes;
but have not been used
for predicting breeding value
of animals, yet.
Now, the data that we work with
in animal breeding
are largely observational
and retrospective.
They consist of farm records
that have been collected
directly on the farm.
And there is a notorious absence
of randomized experiments,
as in human medicine,
mostly because it's impossible
to carry out large animal experiments,
as it is impossible or very difficult
to randomize patients
into clinical trials.
Then, the question of evaluating
the merit of animals
becomes largely a statistical one.
And then, once we have evaluation
of the genetic merit of the candidates.
We decide, which will be selected?
How we are going to be mating
the selected animals?
Are we are going to be mating
relatives with relatives?
Or we are going to avoid
mating relatives?
