Biomedical Engineering Reference
In-Depth Information
digital signal when activated by a radio transmitter.
Adrawbackisthatthetransceiverdeviceusedtoactivate
and read the signal from the implant operates only within
a range of a few inches, up to perhaps a foot, which means
that animals must be physically positioned (if not
restrained) for reading. Another problem lies in the fact
that coding has not yet been standardized so that implants
supplied by one manufacturer cannot be read by equip-
ment provided by another. A serious impediment to their
widespread adoption at the present time is the cost of the
implants and equipment, but these costs have come down
dramatically recently (2010: $25/tag). Nonetheless, when
prices decline sufficiently, implantable transponders
will most likely become the identification method of
choice, even if the reading range cannot be improved
significantly.
(e.g. specific pathogen-free subpopulations) and increas-
ingly closed populations. This information allows for the
calculation of the common measures of the health of
genetic populations: inbreeding and founder representa-
tion. The issue of monitoring and reporting of genetic
health within a nonhuman primate breeding colony is
considered below, in the section “Monitoring genetic
management”. Finally, pedigrees are also crucial for
genetic analyses, which depend on detecting Mendelian
transmission patterns underlying the distribution of
phenotypes in families. These methods have become
a more important aspect of disease model development as
the human gene map has been completed and as serious
efforts at genetic mapping in nonhuman primates have
been completed.
Even when study goals are not explicitly genetic,
pedigrees can greatly enhance the value of research
animals
the assumption of independence between
experimental subjects is a risky one if the animals are all
derived from the same interbreeding colony. Likewise,
many demographic analyses (particularly fertility
measures) require knowledge of parent-offspring identity.
e
Identification of Pedigree Relationships
Another important dimension exists in animal identifica-
tion in addition to simply making sure that one individual is
not mistaken for another. This is identifying the individual
with respect to the relationships that connect it to members
of its family; that is, identifying its pedigree relationships.
In effect, what is required is an unambiguous identification
of the paternity and maternity of each animal. Obviously,
this is a more serious issue in an established breeding
colony, but can also be important in smaller research situ-
ations as the consideration of genomics and shared genetics
becomes a larger part of many studies.
In some colonies it is possible to approach this goal by
caging breeding-age animals either individually or in pairs
so that sire and dam are known. However, it is apparent that
even under these circumstances a certain proportion of
parents (on the order of 5
RECORD KEEPING
In 1979, a Committee on Laboratory Animal Records was
established by the National Research Council in recogni-
tion of the need for common data management practices for
effective primate colony management. In its report
( National Research Council, 1979 ), the committee speci-
fied criteria for a record-keeping system that would:
(1) identify basic information needed for local colony
management; (2) provide basic data for evaluating breeding
programs; (3) provide a uniform compilation of informa-
tion that can accompany individual animals that are trans-
ferred between colonies; and (4) define a set of uniform
record items so that information can be shared among
institutions and used for national planning. Many of these
goals are still under discussion at the time of this writing,
spring of 2010.
Extending this 1979 work, an ad hoc committee formed
at a workshop held as part of the program of the 1987
meeting of the American Society of Primatologists ( Dyke,
1993 ) specified a set of guidelines for standardizing
primate colony data. Variables included in the standard
were limited to the minimum required for basic demo-
graphic analysis and for the construction of extended
pedigrees for population genetic analysis.
Because of the high cost of early technology, comput-
erized record keeping started with the larger institutions
that could afford to develop their own data management
software, which was usually specific for a particular brand
of large central computer. Storage capacities were limited,
which necessitated complex data coding that represented
10%) are misidentified because
of recording and handling errors, escapes, inter-cage
copulations, maternal theft, and switching of infants.
A more satisfactory method of establishing paternity and
verifying maternity is to use genetic marker typing. At the
first writing of this chapter, the major drawback of marker
typing was that it was time consuming and expensive, but
costs and time for this work has dropped dramatically in
recent years, and service labs (e.g. the Veterinary Genetics
Lab in Davis, California) have developed standard sets of
markers to facilitate this work. This technique has the
tremendous advantage of
e
reducing pedigree errors to
extremely low levels.
There are three important applications for this infor-
mation. First, once identity has been established, the
ability to cross-check vital statistics and other management
information between family members offers an extremely
powerful addition to data validation procedures. Second,
accurate information about genetic relationships is critical
for proper genetic management of increasingly fractured
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