Biomedical Engineering Reference
In-Depth Information
underscores that phylogenetic relationships should be
reconstructed from the greatest possible variety of biolog-
ical evidence.
populations of a species (
Nei, 1973
). Both parameters are
important for assessing the suitability of a population of
primates as an animal model for the study of human
disease. Excessive genetic homogeneity precludes the
opportunity to identify genes that influence susceptibility to
specific diseases but minimizes the contribution of genetic
variance to the phenotypic variance, allowing for a better
resolution of experimental treatment effects. For example,
the rhesus macaque model for Krabbe disease in humans is
provided by a very rare mutation that was discovered only
after several generations of intense inbreeding in a lineage
of rhesus macaques (
Luzi et al., 1997
).
Excessive genetic heterogeneity or genetic subdivision
of the population inflates the phenotypic variance of traits
of interest by increasing the contribution of genetic vari-
ance, thereby obscuring experimental treatment effects.
The most genetically diverse of the populations studied by
Nozawa et al. (1977)
were longtail macaques from
Malaysia and rhesus macaques from Thailand, with gene
diversity values of 0.108 and 0.096, respectively. The latter
estimate (if not both) is (are) undoubtedly inflated by
natural hybridization that has occurred between rhesus and
longtail macaques in Indochina. It is noteworthy that
Indochinese longtail macaques comprise the majority of
nonhuman primates now being imported for use in
biomedical research. The least genetically diverse of the
populations studied by them were the two subspecies of
Japanese macaques, M. fuscata fuscata and M. fuscata
yakui, with gene diversity values of 0.019 and 0.000,
respectively. This low level of gene diversity, which mini-
mizes the contribution of inter-animal genetic differences
to the phenotypic differences in experimental effects in
biomedical research, increases the appeal of this species as
an animal model. Both rhesus and longtail macaques
exhibited approximately equal levels of gene diversity, with
Chinese rhesus macaques having about 50% higher diver-
sity than Indian rhesus macaques.
Sooty Mangabeys
The pelage of the sooty mangaby, gray to brown-gray, gives
this species its common name, and considerable size
differences contribute to marked sexual dimorphism in this
species. They are highly vocal animals with longer tails
than their close relatives the baboons. They have grey/pink
faces with black muzzles and ears and long light-colored
cheek whiskers.
African Green Monkeys
Vervets (African green monkeys) are medium sized
primates, smaller than macaques and baboons, with long
arms and legs that are adapted for speed and much less
sexual dimorphism than the baboons and most macaque
species. Their pelage is usually greenish-olive or silver-
gray and the face is black with a white band crossing the
forehead. Social groups practice a distinctive system of
alarm calls that differentiates predators (e.g. snakes, eagles,
and leopards).
Genetic Diversity
Numerous studies of protein coding (electrophoretically
defined serum or erythrocyte proteins and blood group)
polymorphisms were conducted in the 1960s and 1970s that
focused on one or a very few species of nonhuman
primates.
Nozawa et al. (1977)
were the first to characterize
genetic polymorphisms in a broad range of Asian species of
genus Macaca, including M. mulatta, M. fascicularis,
M. fuscata, M. nemestrina, and M. radiata. They reported
differences in allele frequencies for electrophoretically
defined protein polymorphisms among several regional
populations each of M. mulatta and M. fascicularis that
formed reciprocally monophyletic clades in their analysis.
In their study M. arctoides (stump tail macaques) and
M. radiata, both of which Delson includes in his sinica
group of macaque species (
Delson, 1980
), together formed
a sister clade to that containing rhesus and longtail
macaques (in accord with the hypothesis of Tosi et al. of the
origin of M. actoides, discussed above), and pigtail
macaques (M. nemestrina) formed the oldest clade in their
phylogeny. These results are consistent with the discussion
of the phylogeography and evolutionary history of the
macaque species discussed above.
Two parameters that are useful for evaluating the
genetic structure of populations are gene diversity, the level
of heterozygosity expected under Hardy
ABO Blood Groups
While isoimmune antisera were developed to characterize
red cell surface antigen polymorphisms in some species,
the human-like ABO blood groups, which are crucial for
transplatation research using nonhuman primates, have
been characterized in rhesus and longtail macaques using
human reagents. Due to the absence of A and B antigens on
the surface of macaque red blood cells (RBCs), the saliva
inhibition test or reverse typing of NHP sera using human
test RBCs is required for phenotyping the ABO locus in
macaques. The B antigen has been reported to be
predominant in both rhesus (
Moor-Jankowski and Socha,
1978; Lind´n et al., 2008
) and longtail macaques (
Sae-Low
and Malaivijitnond, 2003
) Higher frequencies of A are
found in longtail
Weinberg equi-
librium conditions (
Nei, 1978
), and the level of genetic
subdivision, or genetic differentiation among regional
e
than in rhesus macaques, except
in
