Biomedical Engineering Reference
In-Depth Information
(Mandrillus leucophaeus), gelada “baboons” (Thero-
pithecus gelada), and mangabeys (including species of the
genera Lophocebus, Cercocebus, and Rungwecebus).
Most, if not all, species of Macaca and Papio can
apparently hybridize with each other (and even artifical
inter-generic hybridization has been documented), and
those whose ranges overlap have been documented to do so,
causing reticulation in phenograms and haplotype networks
describing their phylogenetic history. Natural hybridization
between Papio anubis (olive baboons) and Theropithecus
gelada, after nearly 4 million years of divergence, has been
reported (
Dunbar and Dunbar, 1974; Jolly et al., 1997
), and
species of Macaca and Papio have produced hybrid
offspring whose own fecundity is unknown. Not surpris-
ingly, the taxonomic status of at least some alleged species
of both genera is contentious and some taxa now regarded
as species may have arisen from hybridization between
ancient species (e.g. see
Tosi et al., 2000
). It is the
macaques and baboons that have made the most important
contributions to biomedical research. These two genera of
papionins, Macaca and Papio, may have diverged from
each other as early as 9
monophyletic groups of species with an initial bifurcation,
some 4
5 mya, between a presumed silenus (nemestrina-
like) progenitor and a fascicularis-like ancestor from which
all non-silenus group species later evolved. Based on
discrepancies between mtDNA and Y-chromosome
phylogenies of macaque species,
Tosi et al. (2000)
have
argued that the ambiguous relationship of M. actoides to
both the fascicularis and the sinica groups of macaque
species is resolved by the origin of M. arctoides by
hybridization between a M. assamensis/M. thibetana and
a fascicularis-like ancestor. The living species of the
silenus, sinica, and fascicularis groups of macaques share
a common ancestor that lived approximately 3.5 mya,
2.5 mya, and 1.5mya, respectively. Thus, of these five
macaque species, M. nemestrina is the most divergent
followed by M. radiata and M. fascicularis, while
M. mulatta, M. cyclopis, and M. fuscata were the last to
evolve (in that order), from the fascicularis lineage, and
are, therefore, closely related to each other.
The common ancestor to species of the fascicularis
group of macaque species probably originated in insular
Southeast Asia, reached the mainland by the middle
Pleistocene (
Tosi et al., 2003
), then diversified, consecu-
tively, into rhesus (M. mulatta), Taiwanese (M. cyclopis),
and Japanese (M. fuscata) macaques (
Fooden, 2006
). The
former and latter species are more closely related to each
other than either is to M. cyclopis.
Rhesus macaques (Macaca mulatta), employed in the
development of poliovirus vaccine (
Sabin, 1985
), were the
first primates to be transgenic, cloned, and sent to space and
are more frequently used as animal models for the study of
human disease than any other nonhuman primate species.
They provide the primary model for research in infectious
diseases, reproductive biology, behavior, neuroscience, and
immunology and more recently have been employed in
research on the human immunodeficiency virus (HIV),
including vaccine development (
Williams-Blangero, 1993;
VandeBerg and Williams-Blangero, 1997; Williams-
Blangero et al., 2002
). Simian Immunodeficiency Virus
(SIV) causes a disease in macaques almost identical to that
(AIDS) caused in humans by HIV. Many specific pathogen
free (SPF) colonies of the species have been derived in the
USA, predominantly for use in research on infectious
diseases that can be confounded by the presence of other
infectious agents. In addition, its genome was the third
among all primates (behind humans and chimpanzees) to
be sequenced (
Gibbs et al., 2007
).
Approximately 60% of the nonhuman primates housed
at facilities supported by the National Center for Research
Resources (NCRR) of the National Institutes of Health
(NIH) are rhesus macaques (
WDRMBMR, 2003
). The
reproduction capacity of these facilities is approximately
1800 rhesus macaques per year, nearly half of which are
used for AIDs-related research,
e
10 mya (
Raaum et al., 2005
). Of
the two genera, it is the macaques that are the more bio-
medically relevant.
e
Macaques
The macaques originated in northeastern Africa perhaps
7 mya and spread through much of continental Asia
between 3 and 5 mya. While there exists no concensus on
classification of the macaques (
Brandon-Jones et al., 2004
),
approximately 20 species are widely recognized, all but one
of which, Macaca slyvanus, a sister taxa to all other
macaque species, are restricted to Asia. These species can
be subdivided into approximately four monophyletic
groups (
Fooden, 1976; Delson, 1980
). Three of these four
groups of species, the fascicularis group (including
rhesus (M. mulatta), longtail (M. fascicularis), Japanese
(M. fuscata), and Taiwanese (M. cyclopis) macaques),
the silenus group (including pigtail (M. nemestrina)
macaques), and the sinica group (including bonnet
(M. radiata) macaques) contain member species that have
been used in biomedical research. Up to seven species of
macaques live on Sulawesi (M. maura, M. tonkeana,
M. ochreata, M. brunnescens, M. hecki, M. ni-grescens,and
M. nigra) but have not been used in biomedical research.
Two species of the sinica group of macaque species,
M. assamensis and M. thibetana, and the newly discovered
species M. munzalla, which they closely resemble due to
either parallel evolution or hybridization (
Chakraborty
et al., 2007
), have also not been used in biomedical research.
In a study of mitochondrial DNA, Y-chromosomes, and
autosomal loci from 19 recognized Asian macaque species,
Tosi et al. (2003)
confirmed the existence of these four
a number
that
is
