Biomedical Engineering Reference
In-Depth Information
are quite closely related to each other, sharing a majority of
their major histocompatibility complex (Mhc;
Doxiadis
et al., 2006
), microsatellite (STR;
Kanthaswamy et al.,
2008a
), and single nucleotide polymorphism (SNP;
Street
et al., 2007
) alleles. They are paraphyletic for parts of their
genomes and serve as models for many of the same human
diseases. Both rhesus and longtail macaques evolved within
adjacent, vast geographical ranges subdivided by
geographical barriers, and consequently are genetically
subdivided into regional populations that exhibit genetic
differences that influence the choice of specific populations
for use as specific animal models. For example, Chinese
and Indian rhesus macaques and Philippine and Indonesian/
Malaysian longtail macaques differ in their response to
experimental infection with SIV and certain Plasmodium
species (P. knowlesi and P. coatenyi), respectively. While
responses to some treatment effects in biomedical research
vary among the regional populations of both species, it is
not yet clear which regional varieties are most suitable for
which animal models.
This problem is exacerbated by the failure of some
biomedical research reports to specify the country of origin
of subjects employed. As with rhesus macaques, most
breeding centers (but not all) avoid hybridizing the regional
varieties of longtail macaques, but some inadvertent mixing
has occurred because regions of origin are sometimes either
unknown, misrepresented by importers, or not considered
important. Although genetic markers have been discovered
that can identify the origin of unmixed regional populations
of both rhesus (e.g.
Smith, 2005; Smith and McDonough,
2005, Smith et al., 2006; Ferguson et al., 2007
) and longtail
(e.g.
Smith et al., 2007; Street et al., 2007; Kanthaswamy
et al., 2008b
) macaques, a sufficient number of highly
informative markers is required to accurately estimate
levels of admixture in individual animals; a panel of such
markers for rhesus macaques was recently developed under
the auspices of the National Nonhuman Primate Research
Consortium's Genetics and Genomics Working Group
(
Kanthaswamy et al., 2009
).
Three additional species of macaques have been
employed, albeit much less frequently than rhesus and
longtail macaques, in biomedical research: pigtail macaques
(M. nemestrina), and, to a lesser extent, bonnet macaques
(M. radiata) and Japanese macaques (M. fuscata).
M. nemestrina, the southern pigtail macaque of the silenus
group of macaques, and M. radiata, the bonnet macaque of
the sinica group of macaques, in descending order, are both
more remote congenerics of rhesus and longtail macaques
and are differentiated from each other by 2
diverged from the western (i.e. Indian) rhesus macaques
within the last few hundred thousand years; they represent
one of, if not the last, recognized macaque species to evolve.
The oldest fossils in Japan might date to as early as half
a million years ago when a land bridge connected the
Korean Peninsula to Kyushu and southern Honshu (
Fooden
and Aimi, 2005
), the two largest islands of Japan that
harbor Japanese macaques. While macaques no longer
inhabit the Korean Peninsula, their fossil remains have been
found there (
Delson, 1980
), and it is reasonable to regard
this region as the homeland of Japanese macaques.
Japanese macaques represent the most northerly distributed
of all nonhuman primates and are found from northwestern
Honshu (but not Hokkaido) southward to Yakushima, south
of Honshu, and throughout Kyushu and Shikoku. The
species is regarded as “threatened” and one of its two
subspecies (M. f. yakui, from Yakushima, the southernmost
members of the species) is endangered and has not been
employed in biomedical research. In Japan, many free-
ranging groups of Japanese macaques, including those on
Kojima, off southwestern Kyushu, Yakushima, south of
Honshu, and Arashiyama, near Kyoto, have been subjects
of extensive behavioral research, and colonies bred for
predominantly behavioral and biomedical research,
respectively, are maintained at Kyoto University's Primate
Research Institute in Inuyama in Aichi Prefecture and at the
Tsukuba Biomedical Primate Research Center in Tsukuba
Science City, Ibaragi Prefecture, Japan. Two large colonies
of Japanese macaques were exported to the USA approxi-
mately 40 years ago, one transferred from Arashiyama to
the South Texas Primate Observatory (now known as the
Animal Protection Institute Primate Sanctuary) in Dilley,
Texas (near Loredo) and another from Mihara City in
Hiroshima Prefecture to the Oregon National Primate
Research Center in Beaverton, Oregon.
The fourth species in the fascicularis group of macaque
species, the Taiwanese macaque, M. cyclopis, is employed
as an animal model in Taiwan, but has seldom been used
elsewhere, and has not yet been bred in captivity for
biomedical research. An exception to this is a colony once
maintained at the New England National Primate Research
Center, but this colony no longer exists. A captive colony of
Taiwanese macaques is maintained at the Institute of
Wildlife Conservation of the National Pingtung University
of Science & Technology in Neipu, Taiwan, and planning is
underway for the establishment of a National Primate
Breeding and Research Center in Taiwan to breed this
macaque species for use in biomedical research.
M. nemestrina was once combined with M. leonina,
northern pigtailed macaques, in a single species, also then
called M. nemestrina, and some confusion in the literature
remains regarding the identity of the species under
discussion. The range of M. nemestrina extensively over-
laps that of M. fascicularis, but far less is known about the
3my of
divergent evolution. M. fuscata, the Japanese macaque, is
more closely related to rhesus macaques than to any other
macaque species, and might have evolved from the ances-
tors of the eastern (i.e. Chinese) variety of rhesus macaques
(
Marmi et al., 2004
) or hybridized with them, after the latter
e
