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High Throughput SSR Multiplex Kits (12plex) for Euphrates’ Poplar, Populus euphratica (Salicaceae)

一种优化的胡杨高效多重 (12重) SSR体系



全 文 :一种优化的胡杨高效多重 (12重) SSR体系∗
徐  放ꎬ 赵  舒ꎬ 邬荣领ꎬ 杜  芳∗∗
(北京林业大学计算生物学中心ꎬ 林木遗传育种国家工程实验室ꎬ 生物科学与技术学院ꎬ 北京  100083)
摘要: 微卫星多重 PCR方法是一种非常经济并且高通量的基因分型技术ꎮ 本研究在耐干旱、 盐碱的胡杨
(Populus euphratica) 中开发出一套荧光标记的 12重微卫星工作体系ꎮ 该体系包含 12条表达序列标签微卫
星 (EST ̄SSR) 引物ꎬ 其中 3条设计于 NCBIꎬ 另外 9条设计于二代的转录组序列ꎮ 利用该多重微卫星体系
可在单一的 PCR反应体系中成功扩增出 12条表达序列标签的微卫星短序列片段ꎬ 并在胡杨的 3个自然居
群 96个个体中对该体系进行了验证ꎬ 结果显示该体系具有很高的稳定性及多样性ꎮ 同时ꎬ 在杨属的 5个
派 7个种中对其通用性进行了检验ꎬ 显示这些引物具有很高的通用性ꎬ 成功扩增率为 79%ꎮ 本研究中提供的
12重多重 PCR结合本实验已经公开发表的 2个 8重体系对揭示胡杨及其他杨树的进化历史具有重要的作用ꎮ
最后ꎬ 本研究认为引物的选择ꎬ 扩增效率ꎬ 哑等位基因的检测是多重体系开发过程中最为关键的步骤ꎮ
关键词: 胡杨ꎻ 多重 PCRꎻ 基因分型
中图分类号: Q 78            文献标识码: A                文章编号: 2095-0845(2014)03-365-10
High Throughput SSR Multiplex Kits (12 ̄plex) for Euphrates’
Poplarꎬ Populus euphratica (Salicaceae)
XU Fangꎬ ZHAO Shuꎬ WU Rong ̄Lingꎬ DU Fang∗∗
(Center for Computational Biologyꎬ National Engineering Laboratory for Tree Breedingꎬ
Beijing Forestry Universityꎬ Beijing 100083ꎬ China)
Abstract: Multiplex PCR of microsatellite is a cost ̄effective and high ̄throughput technique of genotyping. We devel ̄
oped a new 12 ̄plex PCR kit for Populus euphraticaꎬ the only tree species in desert area ranging from Western China
to Mediterranean coast. Three primers were designed for the expressed sequence tags (ESTs) sequences from the
NCBI database and the other nine primers were designed based on the EST sequences of P􀆰 euphratica obtained by
Solexa. The multiplex kit was tested by 96 samples from three natural populations. The results showed sufficient am ̄
plification stability and high polymorphism. All the 12 loci used in this kit showed a high transferability (79%) in
other seven species from five sections of the genus. The new 12 ̄plex kit combined with the two eight multiplex kits
we had developed in previous studiesꎬ should be useful to reveal the genetic mechanism and evolution history of the
P􀆰 euphratica and related species. During the researchꎬ we found that primers selectionꎬ amplification efficiencyꎬ
null allele detection are the essential parts of the multiplex kit development.
Key words: Multiplex SSRꎻ Populus euphraticaꎻ Genotyping
  Populus euphratica Oliv. (Salicaceae)ꎬ a dom ̄
inant arbor tree in the desert regions with relatively
abundant water resources of western Chinaꎬ central
Asian and Mediterranean coast countriesꎬ is the most
植 物 分 类 与 资 源 学 报  2014ꎬ 36 (3): 365~374
Plant Diversity and Resources                                    DOI: 10.7677 / ynzwyj201413151

∗∗
Funding: Doctoral Program of Higher Education of China (2011DD14120014) and Fundamental Research Funds for the Central Universities
(TD 2012 ̄01) to FKD
Author for correspondenceꎻ E ̄mail: dufang325@gmail􀆰 com
Received date: 2013-07-10ꎬ Accepted date: 2013-10-12
作者简介: 徐  放 (1987-) 男ꎬ 博士研究生ꎬ 主要从事植物数量遗传学研究ꎮ E ̄mail: xfang4321@163􀆰 com
salt ̄ and drought ̄tolerant tree species ( Sharma et
al.ꎬ 1999). P􀆰 euphratica is a valuable tree species
used for afforestation on saline and alkaline desert
areaꎬ which plays an important role in maintaining
the ecological equilibrium of desert environments by
sand stabilization and water reservation ( Houꎬ
1985). Howeverꎬ the environment change reduced
the geographic distribution of the P􀆰 euphratica
(Bruelheide et al.ꎬ 2003)ꎬ makes it urgent to en ̄
hance the genetic research in order to protect this
endanger species. Much of the work conducted on
this species to date has focused on the physiological
mechanisms responsible for its resistance to abiotic
factors (Sun et al.ꎬ 2012ꎻ 2013ꎻ Li et al.ꎬ 2013).
In recent yearsꎬ genetic research through molecular
markers in P􀆰 euphratica had gained useful genetic
information to reveal the genetic mechanism of this
species ( Fay et al.ꎬ 1999ꎻ Vonlanthen et al.ꎬ
2010ꎻ Wang et al.ꎬ 2011aꎬ b). Howeverꎬ partly be ̄
cause of the scarcity of suitable molecular markersꎬ
the genetic factors responsible for the ability of
P􀆰 euphratica to cope with various adverse environ ̄
mental conditions are largely unknown. The develop ̄
ment of the sequencing technology makes it easy to
achieve numerous and accurate information to devel ̄
op the molecular markers. It is possible to gain high ̄
resolution molecular data to detect the genetic mech ̄
anism and evolution history of many species. To ob ̄
tain this purposeꎬ we aimed to develop high through ̄
put polymorphic microsatellite kits to speed up and
simplify the large quantity experiment process.
Multiplexingꎬ single PCR involves the co ̄am ̄
plification of multiple lociꎬ can significantly decrease
the genotyping cost and increase throughput ( Gui ̄
choux et al.ꎬ 2011aꎬ bꎻ Lefèvre et al.ꎬ 2011ꎻ Lep ̄
ais et al.ꎬ 2011ꎻ Wanger et al.ꎬ 2012). A Few mul ̄
tiplex PCR methods based on microsatellite were
used in the genus Populus (Euseman et al.ꎬ 2009ꎻ
Liesebach et al.ꎬ 2010)ꎬ in both reports the number
of the amplified loci involved in each multiplex kit
were less than five. Until recentlyꎬ the two multiplex
PCR kits each contains eight SSR loci of P􀆰 euphratica
developed by our group (Xu et al.ꎬ 2013) showed
new lights on the population genetic surveys of this
species. But it still cannot satisfy the large ̄scale mo ̄
lecular mapping experimentsꎬ thus more multiplex
kits were urgently needed.
In this studyꎬ we firstly screened our published
575 polymorphic primers designed from 94 090 non ̄
redundant Expressed Sequence Tags ( ESTs) from
P􀆰 euphratica (Du et al.ꎬ 2013). Secondlyꎬ we scree ̄
ned 61 EST ̄SSRs and designed new primers from
the National center of biotechnology information
(NCBI) database to choose the best set of the prim ̄
ers to optimize the multiplex kit. Finallyꎬ we chose
12 SSR loci with high polymorphismꎬ clear amplicon
signals and proper fragment length for the multiplex
PCR kit.
1  Material and methods
1􀆰 1  Sampling strategy
All the samples were collected from poplar forests
along the Tarim River in west China (Bayinguolengꎬ
Xinjiangꎬ 41􀆰 0325° - 41􀆰 0825° N and 86􀆰 1181° -
86􀆰 4693°Eꎬ Table 1). We sampled adult trees aged
more than 50 years from three main populations. To
avoid taking clonal treesꎬ sample should locate at
least 50 meters from others. In each populationꎬ 32
trees were chosen for further analysis. Totallyꎬ 96
samples were involved in the multiplex experiment.
All the location information (longitudeꎬ latitude and
altitude) for each tree were record. We collected leaf
tissue and preserved in the silica gel to dehydration.
1􀆰 2  DNA isolation
Total genomic DNA was extracted from dried
leaves by hexadecyltrimethylammonium bromide
(CTAB) method (Doyleꎬ 1987) with some modifi ̄
cations (Xu et al.ꎬ 2013). To ensure the follow ̄up
experiment stable and accuracyꎬ the concentration of
the DNA were adjusted to 10 ng􀅰μL-1 using Nano Drop
2000 spectrophotometer (Thermo) in 96 ̄well plate.
1􀆰 3  Multiplex PCR development
We made the alignment for the 94090 P􀆰 euphratica
EST sequences obtained by Solexa (Qiu et al.ꎬ 2011)
663                                  植 物 分 类 与 资 源 学 报                            第 36卷
and EST sequences in the NCBI database. Of the
NCBI sequencesꎬ most of them can match to the So ̄
lexa data but the rest of the NCBI sequences still
contained a numerous of genetic information. To en ̄
rich the primer resourcesꎬ we decided to design new
primers base on the unmatched sequences from the
NCBI database. After the screeningꎬ we found 203 of
the unmatched sequences contained the SSR loci.
Based on these sequencesꎬ we designed 20 pairs of
primers using Primer3 (http: / / primer3􀆰 sourceforge􀆰
net / ) . Two individuals were chosen for the origin
screening and removed primers with low amplicon ef ̄
ficiency. Polymorphism test of the newly designed
primers were using the M13 ̄tail technique (Schuelkeꎬ
2000) with 12 random samples. Each reaction con ̄
tains three types of primers: a 5’ M13 ̄ tailed for ̄
ward primerꎬ reverse primer and a fluorescently la ̄
beled M13 primer ( four kinds of fluorescently la ̄
beled M13 primers were used in this researchꎬ sepa ̄
rately carrying 6 ̄FAMꎬ HEXꎬ TARMA and ROX
(Sangon). PCR amplifications were performed by a
Biometra Thermocycler ( Biometra). 0􀆰 5 μL PCR
products of four different fluorescently labeled prim ̄
ers were blended and added to 10 μL formamide.
The resulting mixture was analyzed on an ABI 3730
Prism genetic Analyzer (Applied Biosystems) with
LIZ ̄500 standard size ( Applied Biosystems). The
raw data of the amplify products was measured using
GeneMarker Version 1􀆰 75 ( Softgenetics). Markers
with low ̄quality profiles (poor amplificationꎬ stutter
or obvious presence of null alleles) should not be
used in following experiment. Previous research a ̄
bout P􀆰 euphratica population shows that the popula ̄
tions is significant Hardy ̄Weinberg disequilibriumꎬ
thus we used another method to detect null allele exist ̄
ence. Twelve half ̄sib families (each with one female
parent and seven offspring) were amplified using all
candidate markers by simplex PCR. We assumed
that the locus carry a null allele if any homozygous
offspring shows an allele that was not observed in the
female parent. We also chose former developed EST ̄
SSR primers ( Du et al.ꎬ 2013)ꎬ whose loci had
been tested by random P􀆰 euphratica samples in a
similar way mentioned above during the develop ̄
ment. A total of 63 penta ̄ or hexa ̄nucleotide primers
were selected as candidate (Table 2 and Table S1ꎬ
initial with U). Considering the PCR products length
and the reactions between the different primersꎬ we
used Multiplex Manager (Holleley and Geertsꎬ 2009)
and AutoDimer (Vallone and Buttlerꎬ 2004) to choose
the best primer combination. Finally 12 primers were
selected for the multiplex kit and each forward prim ̄
er was labeled with one of the fluorescent dyes 6 ̄
FAMꎬ HEXꎬ TAMRA and ROXꎬ separately.
Qiagen Multiplex PCR kit (Qiagenꎬ Germany)
was used to perform the amplification of the multi ̄
plex experiment. Following the manufacturer’ s in ̄
structionsꎬ 3 μL Qiagen Multiplex Master Mixꎬ 5 μL
primer premix and 2 μL template DNA were added
into a microtube to perform the reaction. The dye la ̄
bels used for each primer pair in the primer premix
were shown in Table 2. To reduce the costꎬ we lower
the concentration of the Master Mix to 0􀆰 6× and the
results showed similarly to the manufacturer recom ̄
mended concentration (2×). PCR cycling parameter
was following the Qiagen Multiplex PCR kit hand ̄
book strictly with a 95 ℃ denaturing for 15 min fol ̄
lowed by 30 cycles consisting of a 94 ℃ denaturing
for 30 sꎬ a 55 ℃ annealing for 1 min and a 72 ℃ ex ̄
tension for 45 sꎬ and a final 60 ℃ extension for 10
min. 1􀆰 5 μL PCR products were analyze using the
ABI ̄3730 (Applied Biosystems) and the GeneScan
500 LIZ (Applied Biosystems) internal size stand ̄
ard. We adjusted the concentration of each primer
pair according to the preliminary amplification to en ̄
sure the PCR results of each primer show similar
concentration.
1􀆰 4  Microsatellite scoring and binning
We used GeneMarker Version 1􀆰 75 (Softgenet ̄
ics) to determine the genotypes of all the samples.
To eliminate the potential error and obtain the final
genotypeꎬ the FLEXIBIN Excel macro (Amos et al.ꎬ
2007) was used to bin the raw data . As the FLEXI ̄
BIN was designed for di ̄loci onlyꎬ we used AutoBin
7633期        XU Fang et al.: High Throughput SSR Multiplex Kits (12 ̄plex) for Euphrates’ Poplarꎬ Populus 􀆺       
Fig􀆰 1 (a) Raw allele size distribution for the 12 Populus euphratica derived SSRs included in the multiplex kitꎻ (b) Example of a
typical electropherogram profile for a single individual using the multiplexed PCR protocol and kit. Triangles indicate different alleles
at each locus. Orange peaks correspond to the 500 LIZ internal size standards and the numbers in orange show the length ( in bp) of
each standardꎻ (c) Diagram showing allele size range and the fluorescent dyes used for the eight multiplexed lociꎻ the horizontal axis
shows the size range for the alleles (bp)
863                                  植 物 分 类 与 资 源 学 报                            第 36卷
Table 1  Geographical locations of the three Populus euphratica stands examined in this study
POP Code Site name Number of individuals analyzed Latitude (N) Longitude (E) Altitude / m
Pop 1 Xinjiang Group 1 32 41􀆰 0526° 86􀆰 4693° 884
Pop 2 Xinjiang Group 2 32 41􀆰 0825° 86􀆰 1181° 891
Pop 3 Xinjiang Group 3 32 41􀆰 0325° 86􀆰 2289° 888
(http: / / www4􀆰 bordeaux ̄aquitaine􀆰 inra􀆰 fr / biogeco /
layout / set / print / Ressources / Logiciels / Autobin) mac ̄
ro to bin the raw size data of the tri ̄and hexa ̄nucle ̄
otide loci.
1􀆰 5  Error rate measure and diversity analyses
Two researchers interpreted the genotyping re ̄
sults (Guichoux et al.ꎬ 2011b). If a disagreement
showed up between two different readersꎬ we tried to
consult an identical genotype. Ambiguous data which
were hard for the two readers to determine a consen ̄
sus genotypeꎬ we treated them as missing data. In ̄
consistencies were counted and separated as type A
(when an allele was detected by only one reader)
and type B (when the two readers selected different
alleles for the same sample).
We tested the HWE of the 96 samples in the
whole population level and in the subpopulation level
at all 12 loci. We used an exact test ( Guo and
Thompsonꎬ 1992) based on 1 000 000 Markov chain
iterations in ARLEQUIN 3􀆰 5􀆰 1􀆰 3 ( Excoffier and
Lischerꎬ 1989). Bonferroni corrections were applied
for the accuracy of the HWE results (Rice et al.ꎬ
1989).
We used GenAlEx 6􀆰 41 (Peakall and Smouseꎬ
2006) to calculate the number of alleles (NA)ꎬ ob ̄
served heterozygosity (HO)ꎬ expected heterozygosity
(HE) and the fixation index (FIS) at 12 loci over
the three subpopulations and the whole level. We
used Cervus version 3􀆰 0 (Kalinowski et al.ꎬ 2007)
to calculate at each locus Polymorphism information
content (PIC). The probability of identity (PID) of
each locus was calculated by Identity 1􀆰 0 (Wanger
and Sekcꎬ 1999).
1􀆰 6  SSR transferability
We chose seven poplar species from five sec ̄
tions (Aigeiros Dubyꎬ Tacamahaca Spachꎬ Leucoides
Spachꎬ Leuce Duby and Turanga Bge) of the genus
Populus to examine the transferability of all 12 SSR
loci. Four samples of each species were used in the
test and amplified in simplex test over all 12 mark ̄
ers. M ̄13 method ( Schuelkeꎬ 2000) was used for
the experiments and the PCR products were tested
and confirmed by the 2% agarose gel electrophoresis.
2  Results and discussion
2􀆰 1  Multiplex PCR optimization
The result showed that 18 out of the 20 newly
designed primers involved in this research revealed
good amplification efficiency. Two primers were ex ̄
cluded as showed only one genotype over 12 sam ̄
ples. All 63 Solexa based EST ̄SSRs can be detected
with clear signal and without null allele. 16 primers
referenced the NCBI EST database (Table 2 and Ta ̄
ble S1ꎬ initial with G) and the 63 developed EST ̄
SSRs combined the candidate markers. To reduce
the overlap between the PCR productsꎬ we finally
chose 12 primers with relatively smaller range and
proper polymorphism to combine the multiplex kit.
Simplex PCR products of 12 markers involved in
the multiplex kit were sequenced and the data were
submitted to GenBank (Accession No.: JX869047 ̄
JX869058).
2􀆰 2  Error rate measure and diversity analysis
Over all 12 lociꎬ the disagreement rates be ̄
tween two readers were from 0 to 2%. Most errors
(78%) were type Aꎬ a presence allele was missing
by a reader and the heterozygous genotypes being
called as homozygous. Other errors ( 22%) were
type B due to calling a wrong allele. All the disa ̄
greement can be adjusted by two readers rechecking
together and achieve the consistent results. The am ̄
plification failure rate was 1􀆰 6% in total.
9633期        XU Fang et al.: High Throughput SSR Multiplex Kits (12 ̄plex) for Euphrates’ Poplarꎬ Populus 􀆺       
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073                                  植 物 分 类 与 资 源 学 报                            第 36卷
    The HWE condition of the whole population and
subpopulation level were shown in the Table S2.
Most loci showed equilibrium in both levels. The al ̄
lele number (NA) of 12 loci were from 2 to 8 (mean
4􀆰 0)ꎬ the NA of EST ̄SSRs were similar to the re ̄
sults of the primer developing research (Du et al.ꎬ
2013). Compared to the former researches ( Du et
al.ꎬ 2013ꎻ Xu et al.ꎬ 2013)ꎬ loci in this research
showed relatively lower polymorphism. The attribu ̄
tion of this phenomenon might be the repeat number
differenceꎬ the repeat number of hexa ̄nucleotide lo ̄
cus were usually smaller than seven and most of the
di ̄ or tri ̄nucleotide locus contained more than 10 re ̄
peats. Observed heterozygosity (HO) and the expec ̄
ted heterozygosity (HE ) were 0􀆰 13 - 0􀆰 78 ( mean
0􀆰 44) and 0􀆰 10-0􀆰 76 (mean 0􀆰 47). Fixation in ̄
dex (FIS) ranges from -0􀆰 14 to 0􀆰 47ꎬ mean FIS was
0􀆰 084. Polymorphism information content ( PIC) of
all loci was 0􀆰 11 to 0􀆰 73 (average 0􀆰 41). Probabil ̄
ity of Identity (PID) of each locus ranged between
0􀆰 09 and 0􀆰 81 (Table 2).
2􀆰 3  SSR transferability
The overall transferability success rate of the 12
loci in other eight species was 79􀆰 1% (Table S3).
All the12 markers could be amplified in the repre ̄
sent species of Leuce Dubyꎬ Tacamahaca Spach and
Turanga Bge. Howeverꎬ the transferability showed
obvious difference in Aigeiros Duby and Leucoides
Spach. The results indicated that there is positive
correlation between the observed rates of transfera ̄
bility and the phylogeny of the Populus genus (Du et
al.ꎬ 2013).
3  Conclusion
We follow the development trend of the molecu ̄
lar marker technology to develop the high ̄quality
multiplex PCR kit based on the SSR markers. Com ̄
paring to the former research in P􀆰 euphraticaꎬ high
quality of sequence resources could greatly improve
the efficiency of the multiplex developing. Primers
involved in this research represent robust tools for
future population genetic studies and large ̄scale mo ̄
lecular genotyping. With other relative techniquesꎬ it
could help to solve more complex scientific issues. In
additionꎬ the SSR markers can be useful for the mul ̄
tiple studies in other species of Populus genus.
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Table S1  The information of the 67 candidate SSR lociꎬ not including the loci used in the multiplex PCR kit.
All the information based on the simplex PCR in Populus euphratica
Locus Forward primer (5′-3′) Reverse Primer (5′-3′) Motif PIC HE nA Size / bp
G60423 AAAACTCTCCCTCCCTCACT TGGTCTTAGAGAGATTGAAGAAA (CT) 11 0􀆰 141 0􀆰 159 2 110-116
G65676 CAAAAGGGTCTTCCTGTTTC GAGGAGCATCATCAGAGTTG (GA) 10 0􀆰 432 0􀆰 558 3 235-255
G63749 GATCTTCCAATCATGCCTTC CAGCCATTCAAAAAGAGAGA (GT) 11 0􀆰 307 0􀆰 359 3 162-177
G65889 GCACCTCATGTTCCAATCTA GGTGGTAGAGGCTTGAAGAT (AAGCCA) 4 0􀆰 359 0􀆰 489 2 130-163
G60080 CCAAAAACACAAGGTGAAAA TATTTGCCTTTCTGGGACTT (CAT) 6 0􀆰 163 0􀆰 177 3 160-256
G60055 AAAAGCTCTCTGTCTCACTCA CACGTGTAGAGAGGGCAATA (AGA) 6 0􀆰 6 0􀆰 692 4 162-258
G70707 GCGATATTTCAATCCTCATC TCCTACATTGCTTGGCTCT (GCT) 6 0􀆰 15 0􀆰 163 3 195-201
G60512 GAAGATAATGGATGGTGGTG TACATCTCCTGATCCTCCAA (GAC) 12 0􀆰 681 0􀆰 736 7 205-257
G71407 TTAAAGATCAGGGCTTTCCT TCCCATGAGCATGGTAAC (TCC) 10 0􀆰 553 0􀆰 654 3 236-259
G68250 AACCCTCCCAATTGACTCT TGAAGGATTCTGTGCTTTGT (CTCC) 5 0􀆰 668 0􀆰 749 5 170-233
G64109 AACAAACGAAGTGATGGAGA TCACTGGCTTGATAGGAGAA (TCTTC) 4 0􀆰 618 0􀆰 725 4 169-179
G70287 AAACCCAACAAAAGAGGAAA GGTCCTCTTCTTCTTCTCCA (GGTGGA) 5 0􀆰 326 0􀆰 363 4 228-254
G61298 AAAAGGCAAACCCTCCTC CATCTTTCTCTTTCTGTTTCTTAT (CCT) 10 0􀆰 371 0􀆰 424 3 185-191
U46752 CAGGATCCGTTTCCGTTTC TGGTCGCATAAAGAGAGAGAGA (GGAAA) 6 0􀆰 505 0􀆰 593 4 290-304
U17422 TCAGGCACCATACTCACCTG GAGGCGGTTCTTCTTTTGTG (GAACT) 4 0􀆰 397 0􀆰 467 3 299-307
U19370 CTTCCCGATGACCTTAACCA CGACTTTGCTGCTCATACCA (TCTTC) 4 0􀆰 661 0􀆰 753 4 309-323
U1098 GAGCCATTAACGACTGCACA AAGAAGACATTGCTCCTCCTC (GGAGA) 5 0􀆰 141 0􀆰 159 2 216-219
273                                  植 物 分 类 与 资 源 学 报                            第 36卷
Table S1 continued
Locus Forward primer (5′-3′) Reverse Primer (5′-3′) Motif PIC HE nA Size / bp
U4696 CATATCTACCCGCTCCCAGA AGAAAGCCCTCGAAGAAAGC (AACCCC) 4 0􀆰 318 0􀆰 416 2 325-340
U11686 TCACTCCAACCACTTCCACA GAAGACCAAATTGAGCGCAT (AAAAG) 4 0􀆰 077 0􀆰 083 2 329-344
U4068 AAACGACCGCAAAACACTCT CGCCATTATCATTTGCACAC (TCTCC) 5 0􀆰 239 0􀆰 29 2 550-555
U33995 TTAGCCCATCGATCTTGACC AAAACCTGGAAGCTGTGTGG (ACACA) 5 0􀆰 373 0􀆰 519 2 369-375
U69855 GGCTAACAGAAGGCTACTTGC CAGGGGACATCCTCTTCTGA (TTTTC) 4 0􀆰 141 0􀆰 159 2 399-404
U6496 GTAAACAAAGGGACCCCTCC CCCAAATCCCCAATTATTCC (TTCTT) 5 0􀆰 083 0􀆰 091 2 396-406
U865 AAGTCGTCGGGTTGTTGAAG CCCCCTTATCCCTGAAATGT (ATTTT) 4 0􀆰 368 0􀆰 507 2 417-424
U26999 CCCCTGCATTAAAACATCTCA GAAGTTCGTCCCGAATGAAG (ACACAA) 3 0􀆰 141 0􀆰 159 2 294-300
U23208 ATGCATGGTGAACATGAGGA CACATGCATAGTTCAACGGG (TTTCAG) 3 0􀆰 365 0􀆰 505 2 297-300
U1998 CTTTCCCCCTTTTCCTGTTT CCCAAATCGAGATCGAAAAA (TTTTTG) 3 0􀆰 41 0􀆰 475 3 295-307
U40157 GAACCTATTCCAAGCCCTCC AAAATGGTTCTCCTGATGCG (CAGCTG) 3 0􀆰 34 0􀆰 455 2 420-432
U34999 AATCCCTCTTTTTCCTTGCC GTGCCAGTTGTGTACGTTGG (CAAGAA) 3 0􀆰 212 0􀆰 236 3 297-303
U26839 ATCGCCTCATTTTCAACACC ATAGACATGGTCCCCAGCAA (AAACAA) 4 0􀆰 523 0􀆰 605 4 291-308
U86755 CTAGATGCTGAGCTTGCGCT CTCCTTCTTCCTCGCCATC (GCGATG) 4 0􀆰 208 0􀆰 247 2 298-305
U4192 GCAGTGGAGAAGAAGCATCC CGTTGCTTTCGCAGACAATA (AAAAAT) 3 0􀆰 083 0􀆰 091 2 302-303
U55520 GCATAATCTATGCCGCGAAT GCGCCTAACACCAGGTAAAT (AAAAAT) 3 0􀆰 422 0􀆰 541 3 302-306
U17155 TCTGCTGAAAGAAGCTGCAA TGGAACAGCTTGGAGAATCC (GACTTG) 4 0􀆰 152 0􀆰 173 2 318-323
U17138 TGATGCAAAGAGTTGGCAAG CCCATAACAAGGAAAACGTCA (AGAGGG) 4 0􀆰 083 0􀆰 091 2 298-317
U6435 TTTGTGATCATCAGCATTTTCA ACGGGTGGTGATTGATGAGT (AGAAAA) 3 0􀆰 228 0􀆰 255 3 302-317
U70030 ACACGGGTTCTAGTCGTTGG CATGCATTTCTTTGTTGCGT (GAAGAT) 3 0􀆰 152 0􀆰 173 2 317-324
U17155 TCTGCTGAAAGAAGCTGCAA TGGAACAGCTTGGAGAATCC (GACTTG) 4 0􀆰 373 0􀆰 518 2 299-309
U4073 GATGGTCCCAATGAGCAAGT TTCCGCCTTGATCGTTTATC (GATTCA) 4 0􀆰 141 0􀆰 159 2 310-322
U89961 CACAGCTCCCTCCATGATTT CCGAGAAGGTGAGACTTTGC (ATATAC) 12 0􀆰 605 0􀆰 654 8 278-337
U29206 GCTGTAGCCTGTTAAGGTCTGG CCTTCCTCCCTCATAAACCA (GAAAAG) 3 0􀆰 228 0􀆰 255 3 316-320
U28990 TTTGTCGAGATTACCCGACC TCCGATGAACCTCCAAACTC (CAGGTG) 3 0􀆰 083 0􀆰 091 2 330-336
U57819 GTCTCCATCGTGCACTGAGA TTGCAACATGTCCATACATAGAG (TTTCCT) 3 0􀆰 152 0􀆰 173 2 313-317
U64791 TGTCAGCTCTTCACCACCTG CAGAAAGGGAGAACCCACAA (GAGCTG) 3 0􀆰 346 0􀆰 533 2 297-326
U61496 CCTGGGAAGTTGAGGACAAA CCGAATGCATGAACAAGAAA (TTTTTA) 3 0􀆰 178 0􀆰 209 2 306-308
U14044 CGAAGGATTTACAAACGGGA ATGGTGGGGGTTGGATAGAT (ATGCAT) 3 0􀆰 282 0􀆰 325 3 315-326
U15575 CTCTCTTCGAGCGTGCTCAT CGATCGAGTGAACCCGTAAT (AAATTA) 3 0􀆰 275 0􀆰 344 2 324-332
U30602 TGCTTGTTCATGATCCTTCAA TGGGTAGATGAAGACCCTGG (CCAGGA) 3 0􀆰 083 0􀆰 091 2 523-539
U7130 CGCACAAAGAAACATGCAAT ATTTCACCTCCAACAAGGCA (TTTGTT) 3 0􀆰 141 0􀆰 159 2 326-331
U34557 ATGGGCTTCATAGGCCTTCT ATTCCGATCATCAGGTCTGC (GCAGCT) 3 0􀆰 36 0􀆰 437 3 319-330
U59058 TCAAGTCCCATTTTCTTCCC GGATGAGGAGGACAACGAAA (TCCTCA) 3 0􀆰 427 0􀆰 502 4 309-346
U20318 AAGCTTGTGCCACAGGAAGT TGTACACAAAGGAAGCCACAA (AGGAAC) 3 0􀆰 083 0􀆰 091 2 330-336
U37853 CCTTTGAACGATGACGACCT TGTTAATGCTGAATCTGGCG (CCTGTC) 4 0􀆰 177 0􀆰 195 3 343-355
U87770 TCCCCCTCGTACTCCTCTCT ATTTGGGAACGGAGGTAAGG (GCCACA) 3 0􀆰 208 0􀆰 247 2 352-360
U56237 AGCTAAAAAGAGCAGCGACG CAGAAAACAGCCCGAAGATT (GATTTG) 4 0􀆰 141 0􀆰 159 2 357-359
U3965 CGAAAAGAAAAATCCCCCTT AGCAAAAATGGAGAGCAAGC (CCCTAA) 3 0􀆰 228 0􀆰 255 3 450-455
U85105 CCTTTCTTGGCAGATCCTGT CAAGCGATTGAGGCATGTAA (TCATTT) 3 0􀆰 253 0􀆰 312 2 438-447
U25003 TTTTGAGGCGGTTTACCATC TCAACAATCCCTCACTTCCC (GTTAGG) 3 0􀆰 141 0􀆰 159 2 382-389
U30522 ACTACCACCCGTCGATCTTG CCATCAGATGACCCCTCTGT (TTGCTG) 4 0􀆰 346 0􀆰 377 5 380-392
U16390 TGGAGTCCGAGGAAGAGAGA TCGTCACTTTTGCAAGCATC (TGGGGA) 3 0􀆰 576 0􀆰 636 6 440-460
U21516 CTTCTAGCCGTCCTCCAGTG ACCGTGCAATAGCCTCTGAT (GCCTCC) 3 0􀆰 083 0􀆰 091 2 378-385
U49949 TTCAAAGACAAAAATGGGGC CCATTTCTCTTCATTCATGGC (GCTGTT) 3 0􀆰 325 0􀆰 385 3 389-391
U35955 ACGGAGCAAGAGGAAGTTCA TGCCGGAAATTTCTATCGAG (GCAACC) 3 0􀆰 484 0􀆰 602 3 384-414
U15685 GGGAAGTTAGCTCAGCTCAGAA TCGCGATGTTGTTATTTGCT (GAAAAA) 3 0􀆰 385 0􀆰 45 3 390-401
U12594 TTCGTTCCTCAAATGACAACA TATGCCTAACCCACCAAAGG (ATATTC) 3 0􀆰 476 0􀆰 589 3 397-407
U22207 CAGGTCAGGGTCAGAAGGAG TGGCAAAGTGAAAGGAGCTT (AAGAAA) 3 0􀆰 272 0􀆰 304 3 368-409
U5140 AAAGCTAGCAAGGCATGGAG AAGGCCACCTAGCCTGATCT (GAAGAT) 3 0􀆰 195 0􀆰 228 2 408-418
nAꎬ total number of allelesꎻ HEꎬ expected heterozygosityꎻ PICꎬ Polymorphic Information Content
3733期        XU Fang et al.: High Throughput SSR Multiplex Kits (12 ̄plex) for Euphrates’ Poplarꎬ Populus 􀆺       
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473                                  植 物 分 类 与 资 源 学 报                            第 36卷