Lecture: Transgenesis
Genetic standardization
You can have genetically uniform animals and you have genetically variable animals.
Genetic standardization depends all on the experiment you are doing. Someone might
react differently to an influenza vaccination then someone else for example.
A very high genetic diversity in your animals makes it more difficult to reproduce your
experiment. If it is more difficult to describe your experiment and if the animals you are
using are for example not available in the US, it is very hard for researcher in the US to
reproduce your experiment.
The genetic background of our animals used to be checked via skin transplantation.
Nowadays we simply take a piece of the tail and check for the genetic background of our
animals e.g. monogenic characteristics such as color genes, immunogenic markers, DNA-
markers, ….
Genetically undefined strains
In experiments only purpose-bred mice can be used since you can just go out in the
forest and catch mice. There are companies that do this for you but it is very difficult to
maintain a genetic heterogeneous population:
- You have to allow inbred in some fashion
- Mating does NOT happen at random. This has to be monitored at all time
(monitor coupling of animals)
- They have to avoid artificial or natural selection
One advantage is that there is no inbred depression. You don’t have the disadvantages
of inbred animals.
Saif Haify Laboratory Animal Science – Summary 6-November-2015
, Characteristics of outbred animals (advantages)
These outbred animals are cheap and the animal is its own control. Outbred animals
are randomly bred for 4 generations. A maximum of 1% increase of the coefficient of
inbred per generation is allowed.
Disadvantages of these animals:
- Genetically heterogeneous (each individual is unique) à high variability and a lot
of different responses in your experiment
- You need more animals to produce statistically sound results due to the
increased variability
- Historical data are irrelevant
You use these outbred animals only:
- When the genetic background is not relevant
- Within animal experiments
Nomenclature
Xxxx or X1523
Some outbred animals..
ICR-Mouse New Zealand White rabbit
Sprague Dawley Rat Dunking Hartley guinea-pig
Saif Haify Laboratory Animal Science – Summary 6-November-2015
Genetic standardization
You can have genetically uniform animals and you have genetically variable animals.
Genetic standardization depends all on the experiment you are doing. Someone might
react differently to an influenza vaccination then someone else for example.
A very high genetic diversity in your animals makes it more difficult to reproduce your
experiment. If it is more difficult to describe your experiment and if the animals you are
using are for example not available in the US, it is very hard for researcher in the US to
reproduce your experiment.
The genetic background of our animals used to be checked via skin transplantation.
Nowadays we simply take a piece of the tail and check for the genetic background of our
animals e.g. monogenic characteristics such as color genes, immunogenic markers, DNA-
markers, ….
Genetically undefined strains
In experiments only purpose-bred mice can be used since you can just go out in the
forest and catch mice. There are companies that do this for you but it is very difficult to
maintain a genetic heterogeneous population:
- You have to allow inbred in some fashion
- Mating does NOT happen at random. This has to be monitored at all time
(monitor coupling of animals)
- They have to avoid artificial or natural selection
One advantage is that there is no inbred depression. You don’t have the disadvantages
of inbred animals.
Saif Haify Laboratory Animal Science – Summary 6-November-2015
, Characteristics of outbred animals (advantages)
These outbred animals are cheap and the animal is its own control. Outbred animals
are randomly bred for 4 generations. A maximum of 1% increase of the coefficient of
inbred per generation is allowed.
Disadvantages of these animals:
- Genetically heterogeneous (each individual is unique) à high variability and a lot
of different responses in your experiment
- You need more animals to produce statistically sound results due to the
increased variability
- Historical data are irrelevant
You use these outbred animals only:
- When the genetic background is not relevant
- Within animal experiments
Nomenclature
Xxxx or X1523
Some outbred animals..
ICR-Mouse New Zealand White rabbit
Sprague Dawley Rat Dunking Hartley guinea-pig
Saif Haify Laboratory Animal Science – Summary 6-November-2015
