Biomedical Engineering Reference
In-Depth Information
P. h. cynocephalus, and P. h. ursinus as originally argued by
Jolly (1993)
and supported by the studies of
Disotell (2000)
and
Rogers (2000)
. Nevertheless, the wisdom of inter-
breeding different regional populations of baboons, which
is commonly practiced at many breeding facilities, should
be empirically evaluated by comparing phenotypic
responses of different unmixed subspecies of baboons to
experimental treatment effects.
markers known to be highly polymorphic in one species,
such as baboons, to assess genetic characteristics in
a different species introduces ascertainment bias into
results of that study, usually leading to underestimates of
genetic diversity in the latter species. While no evidence of
genetic subdivision in this small sample was found, further
studies should be conducted to eliminate this possibility for
the Caribbean African green monkeys. In coordination with
the impending draft sequence of the vervet genome, the
construction of a vervet-specific SNP map is now underway
and will provide a focus for genotyping vervets from
different regions of Africa.
Mangabeys
Population studies of mangabeys have not been conducted
to characterize substructure, but small samples of manga-
beys from diverse origins have been studied. On the basis of
morphology,
Groves (1978)
concluded that mangabeys are
diphyletic and classified them into two genera: Cercocebus
and Lophocebus, the latter being more closely related to
baboons. Subsequent studies of skeletal and dental
morphology (
Fleagle and McGraw, 1999
) confirmed this
paraphyly of mangabeys and concluded that mandrills and
drills were more closely related to Cercocebus mangabeys
(including sooty mangabeys) and baboons and geladas
were more closely related to Lophocebus mangabeys. This
same conclusion is consistent with Cercopithecoid
phylogenies based on
g
-globin DNA sequences reported by
Page et al. (1999)
and on sequences from five other nuclear
genes (
Harris and Disotell, 1998
).
THE NEW WORLD PRIMATES
Members of the infraorder Platyrrhini, comprising the New
World Monkeys, are limited to the tropical forests of
southern Mexico and Central and South America. They
diverged from catarrhine primates, or Old World Monkeys,
approximately 40 mya and, therefore, are more genetically
diverged from humans than are the cercopithecoid
primates. Based predominantly on morphology, the New
World Monkeys were once assigned to two families, the
Callitrichinae, which includes the tamarins and marmosets,
and the Cebidae, which included all other New World
primates. The tamarins and marmosets are members of the
genera Saguinus and Callithrix, respectively, each of which
is further subdivided into about a dozen different species,
two of which, Saguinus oedipus (cotton-top tamarin) and
Callithrix jacchus (the common marmoset), are far more
widely employed in biomedical research in the USA than
any other Callitrichid. Cebidae had been subdivided into
four subfamilies, two of which, Cebinae and Aotinae, have
contributed genera to biomedical research: Saimiri, the
squirrel monkey, and, Aotus, the owl (or night) monkey,
respectively. The species of squirrel monkey most
commonly used in biomedical research in the USA is the
common squirrel monkey, Saimiri sciureus, while Aotus
nancymaae, the Peruvian red-necked owl monkey, is the
species of owl monkey most commonly used in biomedical
research.
More recent studies based on mtDNA (
Ruiz-Garciacute
and Alvarez, 2003
), DNA sequences of functional genes
(
Schneider et al., 2001; Steiper and Ruvolo, 2002; Opazo
et al., 2006
), Alu insertion elements (
Ray et al., 2004
), and
mixed data sets (
Schneider et al., 2001
) provide strong
support for subdividing Platyrrhini into three monophyletic
families, Atelidae, Pithecidae, and Cebidae, with the last
family, which diverged between 14 and 20 mya (
Steiper
and Ruvolo, 2002
), containing three subfamilies, Cebinae
(squirrel and capuchin monkeys), Aotinae (owl, or night,
monkeys), and Callitrichinea (the marmosets and tamarins)
that arose almost simultaneously and, therefore, are
genetically equidistant from each other (
Schneider et al.,
African Green Monkeys
Relatively few genetic studies of Chlorocebus have been
done, quite fewer than for any of the Panionins. As with
baboons and rhesus macaques, the B phenotype of the ABO
blood group predominates in vervets and the O phenotype
is relatively rare (
Terao et al., 1988
).
Inoue and Takenaka
(1993)
showed that vervet monkeys were polymorphic for
three STR loci identified in Japanese macaques (M. fus-
cata), and the genotypes of four STR loci were recently
characterized in four regional populations of vervets from
South Africa and one from Kenya. While the regional
populations of vervets exhibit marked genetic homoge-
neity, genetic differences between vervet macaques origi-
nating in South Africa and those from Kenya account for
approximately 10% of the total genetic variance in their
combined populations (
Grobler et al., 2006
), suggesting
a moderate level of genetic subdivision among the
subspecies in their natural range.
In a recent study of 55 human STRs known to be
polymorphic in baboons,
Newman et al. (2002)
found that
14 revealed genetic polymorphism in a captive, pedigreed
colony of African green monkeys derived from the
St. Kitts, West Indies colony. The average level of gene
diversity of these loci was 0.72, indicating a level of genetic
heterogeneity approximately equal to that exhibited by
Indian rhesus macaques. It should be recognized that using
