Redesigning Animal Agriculture

plasticity of the genome and the potential
of a species to adapt to new challenges to
its existence. The current genomics revolution
is attempting to unmask these fundamentals
of life in exquisite detail and in
the process will provide tools that enable
greatly improved management of livestock
animals.
Since the dawn of domestication of
plants and animals, perhaps some 8000 to
9000 years ago, humans have been practising
geneticists, enriching for desirable
attributes in these highly selected species
(Wendorf and Schild, 1994). This practice
provided enormous advantage to humans
as food became relatively reliable and abundant
and allowed specialization of humans
for many different tasks within a society.
This in turn fostered the growth of larger
communities and the development of new
knowledge, which reinforced this process.
However, even today there are very few
plants and animals that have been domesticated
compared with the full repertoire
of living organisms. Some do not provide
adequate nourishment compared with the
human effort involved in their production,
others are unsuitable because they contain
toxins or nutritional components not
suitable for human consumption and still
others ‘resist’ domestication because of a
variety of factors including animal social
structures and their reproductive strategies.
In the context of Darwinian natural selection
it can be argued that domesticated animals
and plants ‘chose’ humans to facilitate
the survival and selective advantage of their
species. The success of this process is highlighted
by the growing biomass of domesticated
species, often at the direct expense of
non-domesticated species. The phenotypes
and presumably genomes of domesticated
plants and animals of today are generally far
removed from those of their wild ancestors
due to intense selection pressures imposed
by humans. The potential for additional
changes that enhance the productivities of
the industries associated with these domesticated
plants and animals, while minimizing
their environmental footprint, is clear.
Just as the 1970s was the decade of electronics,
the first decade of the new century
The Impact of Genomics 47
heralds the era of genomics and the promise
of major advances in biology. In the livestock
industry the ultimate benefits of genomics
technology, which largely exploits the natural
genetic variation in livestock animals,
will be increased food production and quality
for lower cost, enhanced food safety, a
reduced environmental footprint and the
development of novel foods with enhanced
health, nutritional and lifestyle benefits.
Importantly, these gains will be achieved in
a manner that does not overly burden the
animal itself.
Genomics
What is genomics? It means different things
to different people but it is largely the study
of the totality of the activities of all genes
within an organism and how they express
themselves in the different physical traits of
a species, breed or individual. Operationally,
genomics is defined as the science of simultaneous
investigations of the structure and
function of very large numbers of genes in
the context of the entire DNA sequence of an
organism. Animal breeders have been practitioners
in the field for many thousands
of years and this has markedly increased
the economic value of many agriculturally
important species. In this traditional activity,
selection is based on observable characteristics
of an animal but without knowledge
of the genes that underlie the selected trait.
There are some limitations to this breeding
strategy, however, especially for selection of
traits that are difficult or expensive to measure,
have low heritability, are negatively
correlated with other economically important
traits or appear late in development
and cannot be measured until the animal
has contributed to the next generation. The
difference now is that molecular tools based
on DNA sequence information are available
to understand, direct and speed the process
of selection of animals and plants with
desirable traits.
The new genomics capabilities are the
result of the confluence of new technologies –
molecular biology, chemistry, electronics,