Botanical Studies (2006) 47: 83-88.
*
Corresponding author: E-mail: sfhuang@nhcue.edu.tw;
Fax: 886-3-525-7118.
Migration of
Trochodendron aralioides
(Trochodendraceae)
in Taiwan and its adjacent areas
Shing-Fan HUANG
1,
* and Tsan-Piao LIN
2
1
Department of Applied Science, National Hsinchu University of Education, Hsinchu 300, Taiwan
2
Institute of Plant Biology, National Taiwan University, Taipei 106, Taiwan
(Received March 23, 2005; Accepted October 3, 2005)
ABSTRACT.
A migratory history of Trochodendron aralioides was postulated by integrating the published
fossil records and the data sets of chloroplast (cp) DNA and allozyme. The populations from Taiwan, the
Ryukyus, and Japan were investigated. The haplotype network of Trochodendron was constructed by the
computer program TCS by taking Tetracentron as outgroup to direct the haplotype network. The paper
shows that Japan¡¦s populations were clearly distinguished from those of the Ryukyus and Taiwan, with
Japan¡¦s being more primitive. Nine substitutions were found between Tetracentron and Japan¡¦s population
of Trochodendron. Based on fossil evidence, taking 50 My (million years ago) as divergence time between
Tetracentron and Trochodendron, the date of separation between Japan and Taiwan¡¦s populations can be dated
to 5.5 My, and the standard error is ¡Ó 2.8 My. Given a likely temperate origin and no extant or fossil plants
discovered in eastern China, the migratory route that led Trochodendron to move into Taiwan was likely
from Japan via the Ryukyus. However, the ancient populations in the Ryukyus should have vanished at least
once as the Ryukyus were submerged around 1.0 My. As a result, the populations now in the Ryukyu Islands
were derived from Taiwan, which is exemplified by the shared haplotype of cpDNA between Taiwan and the
Ryukyus and less heterozygosity in the Ryukyus compared to Taiwan based on allozyme data.
Keywords: Migration; petG-trnP; Taiwan; Trochodendron aralioides.
INTRODUCTION
Historical biogeography is the study of taxa in
space and time including their origin, migration, and
diversification (Myers and Giller, 1988). Explaining
how geological events and/or fluctuations in climate
have shaped the distribution of extant taxa is one of the
main aims of historical biogeography. However, when
the hypotheses of historical events are uncertain, the
distribution pattern of the genetic polymorphisms of the
focused taxa may provide another line of evidence with
which to test their soundness.
Taiwan is a continental island adjacent to mainland
China, the Ryukyus, and Japan. Migration of plants
through oceanic barriers to Taiwan may be due to former
landbridges or to long distance dispersal. Landbridges
are the direct connection between landmasses that make
the migration of taxa possible. Three hypotheses on
landbridges between Taiwan, the Ryukyus and Japan since
the late Miocene have been proposed (Ota, 1998). They
can be summarized as follows: Hypothesis I, proposed
by Kizaki and Oshiro (1977), postulated that a landbridge
connecting southeastern China, Taiwan, and the Ryukyus
was formed in the early Pleistocene about 1.5 My
(million years ago) and might have lasted to the middle
Pleistocene about 1 My. Hypothesis II, developed by Ujiie
and his colleague (Ujiie, 1990; Ujiie et al., 1991; Ujiie
and Nakamur, 1996), postulated (1) that one landbridge
connected the Asian continent, Taiwan, the central and
northern Ryukyus, and Japan in the late Miocene and
that the connection between Taiwan, the Ryukyus, and
Japan was broken during the Pliocene; (2) that another
landbridge connected southeastern China, Taiwan, and
the Ryukyus (excluding the islands of southern Ryukyus)
during the late Pleistocene about 20000 years ago; (3)
that another landbridge might have connected Taiwan
and the islands of the southern Ryukyus about 3800 years
ago. Hypothesis III was proposed by Kimura (2000). It
postulated (1) that one large landbridge connected the
Asian continent, Taiwan, the Ryukyus, and Japan during
the period of 1.6-1.3 My; (2) that the other landbridge
connected southeastern China and Taiwan, and extended
in one direction to eastern China and in the other direc-
tion to the Ryukyus during the period of 1.3-1.0 My; (3)
that the other landbridge connected the Asian continent,
Taiwan, and the Ryukyus and might have extended to
Japan about 0.2 My. After 0.2 My, only the southern
Ryukyus connected with Taiwan.
eCOlOgy
pg_0002
84
Botanical Studies, Vol. 47, 2006
In summary, Taiwan might have been connected with
the Asian continent several times in different geological
periods. The landbridges connecting Taiwan and Japan
through the Ryukyus were proposed in three different time
periods. (1) Ujiie and his colleague think they occurred
from the late Miocene perhaps to the early Pliocene,
about 5 My. (2) Kimura believes they occurred in the
Pleistocene about 1.6-1.3. (3) It occurred about 0.2 My
proposed by Kimura. The landbridges connecting Taiwan
and the Ryukyus were proposed in four different time
periods. (1) Kizaki and Oshiro placed it in the Pleistocene
1.5-1.0 My, and Kimura 1.6-1.0 My. (2) It occurred during
0.2-0.04 My proposed by Kimura, but this landbridge
only connected Taiwan and the southern Ryukyus. (3)
It occurred about 0.02 My proposed by Ujiie and his
colleagues, but this landbridge excluded the southern
Ryukyus. (4) It occurred about 3800 years ago proposed
by Ujiie and his colleague, but this landbridge only
connected Taiwan and the southern Ryukyus.
A calibration of divergence time may be performed
from a molecular substitution rate because genetic
mutation accumulates over time (Li, 1997). Thus,
molecular phylogeny provides us information about the
timing of historical events and reduces our reliance on
the timing of geological events and/or fossil records.
However, molecular phylogeny provides only weak
information about taxa in space, as extinction events
are not reflected in the gene tree with extant taxa. As a
result, to reconstruct a historical biogeography of a certain
taxon requires the incorporation of fossils and gene trees
(Manchester and Tiffney, 2001; Tiffney and Manchester,
2001). Fortunately, fossil records related to Trochodendron
have been reviewed recently (Pigg et al., 2001). Thus,
integrating fossil data and gene tree information to better
understand the phytogeography of Trochodendron is now
possible.
Trochodendron is characterized by a tree habit with ves-
selless wood, alternate leaves in a pseudowhorled arrange-
ment, flowers without sepals and petals, stamens in three
to four whorls, and many fused carpels with free stigmas.
The flowers are dichogamous, self-incompatible, and ob-
ligatorily xenogamous (Chaw, 1992). Phylogenetically, it
is closely related to Tetracentron based on DNA markers,
including 5.8S nuclear ribosomal (nr) DNA, trnL intron
chloroplast (cp) DNA, and rbcL-atpB intergenic spacer
cpDNA (Wu et al., 1999; Wu, 2001). These two genera
are grouped as the family Trochodendraceae or as separate
families and were considered as primitive in Hamamelidae
(Lu et al., 1993). Trochodendron aralioides is the only
extant member of Trochodendron and is distributed in Ja-
pan, the Ryukyus, and Taiwan (Wu et al., 2001). Allozyme
data suggest that Japan¡¦s populations are differentiated
from those in the southern Ryukyus and Taiwan (Wu et al.,
2001), as indicated by cpDNA data (Huang et al., 2004).
Huang et al. (2004) investigated the genetic structure of
all sampled populations and inferred a possible refuge in
the north-central part of the west of the Central Mountain
Range in Taiwan during the last glaciation.
In this study, we used Tetracentron as outgroup to
direct the gene genealogy of Trochodendron aralioides
and infer the migratory events involving it in Taiwan and
its adjacent areas by integrating the data of fossil records
and the genetic information of allozymes and cpDNA.
MATeRIAlS AND MeTHODS
Sampling
A total of 24 populations were sampled, including 20
from Taiwan and two each from the Ryukyus and Japan
as described before (Huang et al., 2004: Table 1), and
each population was represented by four individuals at
least 50 meters apart. An outgroup, Tetracentron sinense,
was collected from one tree in the botanical garden of
the Kunming Institute of Botany, Chinese Academy of
Science, which originated from Kaoligongshan, Yunnan.
Fresh leaves were collected from each individual tree, and
they were either desiccated with silica gel and stored in
a freezer (-30¢XC) permanently after complete dryness, or
they were stored in the freezer (-70¢XC) directly.
DNA sequencing
The DNAs were extracted from the sample leaves
using the protocol of Murray and Thompson (1980). The
DNA extracting solution was then used to amplify the
markers for detecting the variation by polymerase chain
reaction (PCR). One marker was used in this study, i.e.
the intergenic spacer of petG-trnP. The primers for petG-
trnP were 5¡¦-GGT CTA ATT CCT ATA ACT TTG GC-3¡¦
forward and 5¡¦-GGG ATG TGG CGC AGC TTG G-3¡¦
in reverse. The initial denaturing temperature was 95¢XC
for 3 min and then 30 s for each thermal cycle. Thirty
four thermal cycles were given for amplification with the
annealing temperature of 55¢XC for 30 s, and the extension
temperature of 72¢XC for 45 s. The last extension time was
set for 10 min after the completion of 34 thermal cycles.
The PCR products were then purified with the commercial
kit and then sequenced with a sequencing machine
ABI3100 using Big Dye terminator.
Sequence analysis
The sequence of Tetracentron sinense (GenBank
accession number AY835400) was aligned with 95
sequences of Trochodendron aralioides (GenBank
accession number, AY294754-AY294848) by eye. The
computer program TCS (Templeton et al., 1992) was
used to reconstruct the gene genealogy by taking gaps as
missing data.
Fossil records of
Trochodendron
A possible distribution pattern in the past and divergent
history of Trochodendron was described by reviewing the
papers of Jin and Shang (1998), Manchester (1999), and
Pigg et al. (2001).
pg_0003
HUANG and LIN ¡X Migration of
Trochodendron aralioides
85
Molecular dating
Tests of the existence of a constant substitution rate
have been developed, such as the relative rate test (Sarich
and Wilson, 1973) and likelihood ratio test (Goldman and
Yang, 1994) although estimation of constant rate has been
relaxed for different taxa (ref. Near and Sanderson, 2004).
These tests either require three taxa or a phylogenetic
tree for testing or assessing. In this paper, two taxa,
Trochodendron and Tetracentron, were dealt with so
that a test for the existence of a local molecular clock
is out of question. In consequence, such a clock was
assumed to exist in the Tetracentron and Trochodendron
group. The equation K=2RT can then be applied, where
K is the predicted average substitution per site between
two homologous sequences, R is the substitution rate,
and T is the divergence time (Li, 1997). Using the sim-
plest substitution model (Jukes and Cantor, 1969), K=
(-3/4)ln(1-4D/3), where D is the observed average
substitution per site between two homologous sequences,
and the variance of K is D(1-D)/[L(1-4D/3)
2
], where L is
the total length of base pairs (Li, 1997). In practice, D is
represented by N/L, where N is the observed number of
substitution, and L is the total length of base pairs. The
substitution rate R can be calculated by applying known
D and T. D is obtained through observation, and T may
be estimated from fossil records. Once R is estimated, the
divergence time between any two isolated groups can be
calculated when the D between them is observed.
ReSUlTS AND DISCUSSION
gene genealogy of
Trochodendron
A total of 482 base pairs and 96 sequences between
genes petG and trnP were aligned for Trochodendron and
Tetracentron. Thirteen variable sites were detected (Table
1). A cpDNA gene genealogy was reconstructed (Figure
1). There are nine substitutions between Tetracentron,
denoted O in Figure 1, and the closest Trochodendron
haplotype of Aishu, Japan (denoted H in Figure 1). From
haplotype H, haplotype I in Japan and haplotype A in
Taiwan and the Ryukyus are derived. From haplotype A,
haplotypes C and D in Taiwan are derived.
Fossil records of
Trochodendron
Fossils related to Trochodendron, namely Norden-
skioldia Heer and Trochodendroides E.W. Berry, can be
traced back to the late Cretaceous in the higher latitudes
in the Northern Hemisphere, including North America,
Siberia, Japan and northeastern China (Lu et al., 1993).
Nordenskioldia became widespread in the Paleocene in
higher latitudes in North America, Europe, and Asia (Man-
chester, 1999; Pigg et al., 2001). The immediate ancestor
of Trochodendron, the fruit of which is similar to extant
Table 1. Haplotypes of Trochodendron and Teracentron, based on variation of sequence between genes petG and trnP of
chloroplast DNA and their distribution.
Haplotype
Variable site
Distribution
0000122222333
0669756779059
3384258292082
O (Tetracentron)
TCCCGTTTTTGGG
Yunnan (China)
A ( Trochodendron)
CATTGCTGGCATA
Taiwan, the Ryukyus
C (Trochodendron)
CATTGCCGGCATA
Taiwan
D (Trochodendron)
CATTGCCGGCATA
Taiwan
H (Trochodendron)
CATTGTTGGCATA
Aishu (Japan)
I (Trochodendron)
CATTCTTGGCATA
Chomonkyo (Japan)
Figure 1. The gene genealogy of Trochodendron aralioides (A,
C, D, H, I) and Tetracentron sinensis (O) based on a sequence
between genes petG and trnP of chloroplast pDNA reconstructed
by TCS, Version 1.03 by taking gaps as missing data. Sampling
individuals are in parentheses. Haplotypes H and I are restricted
to Japan; haplotype A includes populations from Taiwan and
the Ryukyus; and haplotypes C and D are restricted to central-
north Taiwan. O is the outgroup. One arrow repres ents one
substitution.
pg_0004
86
Botanical Studies, Vol. 47, 2006
Trochodendron and the leaves of which are intermediate
between Trochodendron and Tetracentron (Pigg et al.,
2001), appeared in the early Middle Eocene (49-50 My)
in western North America. Plants of Trochodendron were
also recorded in the Oligocene in Liaoning, northeastern
China (Jin and Shang, 1998), and in the Miocene in west-
ern North America, Kamchatka, and Japan (Manchester,
1999). Manchester (1999) suggested that the migration
of this genus might have occurred through Beringia in an
intercontinental exchange of flora because the occurrence
of the fossil Trochodendron in Europe has been excluded
(Pigg et al., 2001).
Molecular dating: colonization of Taiwan¡¦s
Trochodendron
population
The fossil pollen records of Trochodendron in Taiwan
were found from the peat of the Quaternary between
38000 and 4500 years before the present (BP) (Chung and
Huang, 1972a, b). Since the Trochodendron pollen was
recovered near the bottom of the peat, it was estimated to
have inhabited northern Taiwan for at least 30000 years.
This suggestion seems too recent to give any insight
into the migratory history of Trochodendron. Instead, a
molecular dating is used to estimate the possible timing
o f Trochodendron¡¦s first move into Taiwan. Because
the direct ancestor of Trochodendron, the leaves of
which were intermediate between Trochodendron and
Tetracentron, may be traced to the early Middle Eocene
about 49-50 My (Pigg et al.), we may use 50 My as the
divergence time between Trochodendron and Tetracentron.
Nine substitutions between Tetracentron and Japan¡¦s
Trochodendron and one substitution between Japan and
Taiwan¡¦s populations were detected based on petG-trnP
cpDNA (Figure 1). The divergence time between Taiwan
and Japan, thus, would be about 5.5 My (¡Ü 50*10
6
*ln(1
-4*(1/482)/3))/ln(1-4*(9/482)/3)), and the standard error
would be ¡Ó 2.8 My (¡Ü 50*10
6
*(((1/482)*(1-1/482)/(482*
(1-4*(1/482)/3)
2
))/((-3/4)*ln(1-4*(9/482)/3)). The average
of this dating is consistent with the landbridge connecting
the Asian continents and Japan, the Ryukyus and Taiwan
during the late Miocene and Pliocene proposed by Ujiie
and his colleague, and the timing corresponds to the
incipient emergence of Taiwan.
How did
Trochodendron
migrate into Taiwan.
Considering that Taiwan is the southern limit of the
distribution of the extant Trochodendron, and the fossil
records were only reported in north-eastern China, Japan,
Kamchaka, and North America; the populations of Troch-
odendron in Taiwan should have migrated from the north
instead of from south-western China as suggested by Lu
et al. (1993). This was proposed on the basis of the higher
diversity of the extant Hamamelidae in southwestern
China but was not supported by the fossil records of
Trochodendron. There are two possible migratory routes
for the temperate plants moving into Taiwan from the
North: (1) from the North via continental China to Taiwan
and (2) from Japan via the Ryukyus to Taiwan.
The extant species is only distributed in Japan, the
Ryukyus, and Taiwan while the fossils on the Asian conti-
nent are only recorded in Liaoning and northeastern China
(Jin and Shang, 1998). No fossils have ever been reported
in eastern China. Thus, the first route via continental
China to Taiwan seems unlikely. The likelier route is
thus from Japan via the Ryukyus to Taiwan, which traces
the distribution pattern of the extant species. Moreover,
about 5% of the flora of Taiwan is restricted to Japan, the
Ryukyus and Taiwan (Hsieh, 2002), which implies that
some of these species may have experienced the same
historical events as Trochodendron.
Ryukyu¡¦s extant populations were derivatives
of Taiwan
As the migratory route of Trochodendron is from
Japan via the Ryukyus to Taiwan, the population from
the Ryukyus should be older than Taiwan¡¦s. However,
the Ryukyus¡¦ haplotype of cpDNA is the same as Taiwan¡¦
s and different from Japan¡¦s (Table 1; Huang et al.,
2004). As mentioned by Kimura (2000), the Ryukyus
were submerged around 1 My. As a result, the ancient
populations in the Ryukyus were completely wiped out
at least once. As the haplotype of cpDNA of Amami of
the central Ryukyus is also the same as Taiwan¡¦s (Huang
et al., 2004), a direct connection between them must ex-
ist. The connection between Amami and Taiwan proper
existed until 25000 years ago (Kimura, 2000) during the
last glaciation, or around the 20000 years ago proposed
by Ujiie and his colleague. According to the allozyme
data (Huang et al., 2004: Table 5), the genetic diversity
in Iriomote Island of the southern Ryukyus is the small-
est (H
0
=0.076) in contrast with 0.133 in Erkeshan, 0.131
in Yuanyang Lake, and 0.127 in Taipingshan of northern
Taiwan. The appearance of a population with higher
heterozygosity is either due to being in a distribution
center or being in an area to which individuals have
migrated from two or more distribution centers. The
case of being in a distribution center is more likely as
the populations are located in northern Taiwan, where
a geographical barrier occurs in the north. Higher
heterozygosity in Taiwan¡¦s population suggests a coloni-
zation event from Taiwan to the Ryukyus.
Acknowledgements. The first author would like to give
his cordial thanks to Drs. Xin Tian and Peng Sheng,
Kunming Institute of Botany, Chinese Academic of
Science, for providing materials of Tetracentron.
lITeRATURe CITeD
Chaw, S.M. 1992. Pollination, breeding syndromes, and system-
atic of Trochodendron aralioides Sieb. & Zucc. (Trocho-
dendraceae), a relictual species in Eastern Asia. In C.I. Peng
(ed.), Phytogeography and Botanical Inventory of Taiwan,
Monograph Series No.12, Institute of Botany, Academia
Sinica, Taipei, Taiwan, pp. 63-77.
pg_0005
HUANG and LIN ¡X Migration of
Trochodendron aralioides
87
Chung, T.F. and T.C. Huang. 1972a. Paleoecological study of
Taipei Basin (1), Taipei Botanic Garden. Taiwania 17:
117-141.
Chung, T.F. and T.C. Huang. 1972b. Paleoecological study of
Taipei Basin (2), Neihu profile. Taiwania 17: 239-247.
Goldman, N. and Z . Ya ng. 1994. A codon-bas ed model of
nucleotide substitution for protein-coding DNA sequences.
Mol. Biol. Evol. 1: 725-736.
Hsieh, C.F. 2002. Composition, endemism and phytogeographi-
cal affinities of the Taiwan flora. Taiwania 47: 298-310.
Hu a n g, S .F ., S .Y. Hw a ng . , J . C. Wa n g , a nd T. P. L i n.
2004. Phylogeography of Trochodendron aralioides
(Trochodendraceae) in Taiwan and its adjacent areas. J.
Biogeogr. 31: 1251-1259.
Jin, J.H. and P. Shang. 1998. Discovery of early tertiary flora in
Shenbei Coalfield. Acta Scientiarum Naturalium Universi-
tatis Sunyatseni 37: 129-130.
J ukes , T.H. and C .R. Cant or. 1969. E volut ion of prot ein
mole cules . In H.N. Munro (e d.), Mam mal ian P rotein
Metabolism, Academic Press, New York, pp. 21-132.
Kimura, M. 2000. Paleogeography of the Ryukyu Islands. Trop-
ics 10: 5-24.
Kizaki, K. and I. Oshiro. 1977. Paleogeography of the Rytkyu
Islands. Marine Science Monthly 9: 542-549.
Li, W.H. 1997. Molecular Evolution. Sinauer Associates Inc.
Publishers, Massachusetts, USA.
Lu, A.M., J.Q. Li, and Z.D. Chen. 1993. The origin and disper-
sal of the lower Hamamelidae. Acta Phytotaxonomica Sin.
31: 489-504.
Manchester, S.R. 1999. Biogeographical relationships of North
American Tertiary floras. Ann. Missouri Bot. Garden 86:
472-522.
Manc hes te r, S .R. and B.H. Ti ffne y. 2001. Int egra tion of
paleobotanical and neobotanical data in the assessment of
phylogeographic history of holarctical angiosperm clades.
International J. Plant Sci. 162(S6): S19-S27.
Murray, M.G. and W.F. Thompson. 1980. Rapid is olation of
high molecular weight plant DNA. Nucleic Acids Res. 8:
4321-4325.
My e rs , A.A . an d P.S . G il l e r (e d s .) . 1 9 88 . An a ly t ic a l
Biogeography: an Integrated Approach to the Study of
Animal and Plant Distributions. Chapman and Hall, New
York.
Near, T.J. and M. S anderson. 2004. As sessing the quality of
molecular divergence time estimates by fossil calibration
and fos sil-bas ed model se lection. P hil. Trans . R. S oc .
London B. 359: 1477-1483.
Ota, H. 1998. Geographical patterns of endemism and specia-
tion in amphibians and reptiles of the Ryukyu Archipelago,
Japan, with s pecial reference to their paleogeographical
implications. Researches on Population Ecol. 40: 189-204.
Pigg, K.B., W.C. Wehr, and S.M. Ickert-Bond. 2001. Trocho-
dendron and Nordenskioldia (Trochodendraceae) from the
Eocene of Washington state, U.S.A. International J. Plant
Sci. 162: 1187-98.
S arich, V.M. and A.C. Wilson. 1973. Generation time and
genomic evolution in primates. Science 179: 1144-1147.
Templeton, A.R., K.A. Crandall, and C.F. Sing. 1992. A cladistic
analysis of phenotypic associations with haplotypes inferred
from restriction endonuclease mapping and DNA sequence
data. III. Cladogram estimation. Genetics 132: 619-33.
Tiffney, B.H. and S.R. Manchester. 2001. The use of geological
a nd pa l e on to l og ic a l e vi de n ce in e va l ua t i ng pl a nt
phytogeographyic hypotheses in the Northern Hemisphere
Tertiary. International J. Plant Sci. 162(S6): S3-S7.
Ujiie, H. 1990. Geological his tory of the Ryukyu Island Arc.
In H. Ujiie (ed.), Nature of Okinawa; geomorphology and
geology. Hirugisha, Naha, pp. 251-255.
Ujiie, H. and T. Nakamura. 1996. Temporary change of flowing
route of the Kuroshio Current into the Ryukyu Trough since
the latest glacier period. Chikyu Monthly 18: 524-530. (in
Japanese)
Uji ie, H., Y. Ta naka, and T. Ono. 1991. La te qua rternary
paleoceanographic record from the middle Ryukyu Trench
slope, northwest P acific. Marine Micropaleontology 18:
115-128. (in Japanese)
Wu, J.E. 2001. Part I: Study on the biogeography and the genetic
variation of Trochodendron aralioides; Part II: Phylogeny
of Trochodendron aralioides and its allies in eastern Asia.
Doctoral Dissertation, National Normal Taiwan University,
Taipei, Taiwan.
Wu, J.E., S. Huang, J.C. Wang, and W.F. Tong. 2001. Allozyme
variation and the genetic structure of populations of Tro-
chodendron aralioides, a monotypic and narrow geographic
genus. J. Plant Res. 114: 45-57.
Wu, J.E., W.F. Tung, and J.C. Wang. 1999. Molecular phylogeny
of the lower Hamamelidae based on nucleotide sequences
of trnL intron in the chloroplast DNA. Biol. Bull. National
Taiwan Normal Univ. 34: 137-149. (in Chinese)
pg_0006
88
Botanical Studies, Vol. 47, 2006
©øÄæ¾ð (
Trochodendron aralioides
) ¦b¥xÆW¤Î¨ä¾Fªñ¦a°Ï
¤§¾E²¾¾ú¥v
¶À¬P¤Z
1
¡@ªLÆg¼Ð
2
1
°ê¥ß·s¦Ë±Ð¨|¤j¾ÇÀ³¥Î¬ì¾Ç¨t
2
°ê¥ß¥xÆW¤j¾Ç´Óª«¬ì¾Ç¬ã¨s©Ò
¡@¡@¥»¤å§Q¥Î¤wµoªí¤§¤Æ¥Û¤Î±Ú¸s¿ò¶Ç¸ê®Æ¡A¥]¬A¦P¥\²§ºc.¤Î¸­ºñÅé DNA ¤ù¬q§Ç¦CÅܲ§¡A¨Ó±À´ú©ø
Äæ¾ð¾E²¾¨ì¥xÆW¤Î¨ä¾Fªñ¦a°Ï¤§¥i¯à¾ú¥v¡C©øÄæ¾ð¤§¸­ºñÅé DNA Åܲ§«¬ (haplotype) ¸g¥Ñ¤ñ¸û¥~¸s´Óª«
¡X
ÅK«C¾ð (Tetracentron sinensis)¡A¨Ó»{©w­ì©l«¬¤Î¨ä­l¥Í«¬¡A¤é¥»±Ú¸s¤§Åܲ§«¬¬O³Ì­ì©lªº¡A¦Ó¥B»P¥x
ÆW¤Î¯[²y¤§Åܲ§«¬¤£¦P¡C¤À¤l®ÉÄÁÅã¥Ü¡A¤é¥»»P¥xÆW¤§±Ú¸s¬O¦b 5.5 ¡Ó 2.8 ¦Ê¸U¦~«e¤À¤Æ¥X¨Óªº¡A³o­Ó
®É¶¡¤]¥i¯à¬O©øÄæ¾ð³Ìªì¾E²¾¨ì¥xÆW¤§®É¶¡¡C¦Ü©ó¾E²¾¸ô½³Ì¦³¥i¯à¬O¥Ñ¤é¥»¸g¥Ñ¯[²y¦Ó²¾¤J¥xÆW¡C
¥Ñ©óªñ©øÄæ¾ð¤§¤Æ¥Û¦b¨È¬w¥u¦³¦b¤¤°êªF¥_¡A¤é¥»¤Î³ô¹î¥[¸s®qµo²{¡A±À´ú¥Ñ¤¤°ê¤j³°¾E²¾¤J¥xÆW¤§
¥i¯à©Ê¤£°ª¡C¦Ü©ó²{¥Í¤§¯[²y±Ú¸s¡A±À´ú¬O¥Ñ¥xÆW¾E²¾¹L¥hªº¡A¦]¬°¯[²y¦b¤@¦Ê¸U¦~«e´¿¨I¤J¨ì®ü­±
¤U¡A¬G¦­´Á²¾¤J¤§±Ú¸sÀH¤§®ø¥¢¡C¦P®É¡A¥xÆW¤Î¯[²y¤§±Ú¸s¨ã¦³¬Û¦P¤§¸­ºñÅé DNA Åܲ§«¬¡A¦Ó¥B¦P¥\
²§ºc.¤§§Á²§«×¥_¥xÆW¤§±Ú¸s¥­§¡¤ñ¯[²yªº±Ú¸s°ª¤@­¿¥ª¥k¡AÅã¥Ü¥X¾E²¾¤è¦V¬O¥Ñ¥xÆW²¾¦V¯[²y¡C
ÃöÁäµü¡G¸­ºñÅé DNA¡F¿Ë½¦a²z¡F¥xÆW¡F©øÄæ¾ð¡C