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1.
Xiang-Yang Lou Rory J. Todhunter Min Lin Qing Lu Tian Liu Zuoheng Wang Stuart P. Bliss George Casella Gregory M. Acland George Lust Rongling Wu 《Mammalian genome》2003,14(8):555-564
A canine integrated linkage-radiation map has been recently constructed by using microsatellite markers. This map, with a good coverage of the canine genome, allows for a genome-wide search for the extent and distribution of linkage disequilibrium derived from linkage and evolutionary forces. In this study, we genotyped an outbred pedigree between Labrador retriever and Greyhound breeds with a set of microsatellite markers (240) from the canine linkage map. Linkage disequilibrium was measured between all syntenic and nonsyntenic marker pairs. Analysis of syntenic pairs revealed a significant correlation (–0.229, P < 0.001) between linkage disequilibrium and genetic distance (log transformed). Significant linkage disequilibria were observed more frequently between syntenic pairs spaced <40 cM than those paced >40 cM. There is a clear trend for linkage disequilibrium to decline with marker distance. From our results, a genome-wide screen with markers at low to moderate density (1–2 per 10 cM) should take full advantage of linkage disequilibrium for quantitative trait locus mapping in dogs. This study supports the appropriateness of linkage disequilibrium analysis to detect and map quantitative trait loci underlying complex traits in dogs. 相似文献
2.
Ibrokhim Y. Abdurakhmonov Sukumar Saha Jonnie N. Jenkins Zabardast T. Buriev Shukhrat E. Shermatov Brain E. Scheffler Alan E. Pepper John Z. Yu Russell J. Kohel Abdusattor Abdukarimov 《Genetica》2009,136(3):401-417
Cotton is the world’s leading cash crop, but it lags behind other major crops for marker-assisted breeding due to limited
polymorphisms and a genetic bottleneck through historic domestication. This underlies a need for characterization, tagging,
and utilization of existing natural polymorphisms in cotton germplasm collections. Here we report genetic diversity, population
characteristics, the extent of linkage disequilibrium (LD), and association mapping of fiber quality traits using 202 microsatellite
marker primer pairs in 335 G. hirsutum germplasm grown in two diverse environments, Uzbekistan and Mexico. At the significance threshold (r
2 ≥ 0.1), a genome-wide average of LD extended up to genetic distance of 25 cM in assayed cotton variety accessions. Genome
wide LD at r
2 ≥ 0.2 was reduced to ~5–6 cM, providing evidence of the potential for association mapping of agronomically important traits
in cotton. Results suggest linkage, selection, inbreeding, population stratification, and genetic drift as the potential LD-generating
factors in cotton. In two environments, an average of ~20 SSR markers was associated with each main fiber quality traits using
a unified mixed liner model (MLM) incorporating population structure and kinship. These MLM-derived significant associations
were confirmed in general linear model and structured association test, accounting for population structure and permutation-based
multiple testing. Several common markers, showing the significant associations in both Uzbekistan and Mexican environments,
were determined. Between 7 and 43% of the MLM-derived significant associations were supported by a minimum Bayes factor at
‘moderate to strong’ and ‘strong to very strong’ evidence levels, suggesting their usefulness for marker-assisted breeding
programs and overall effectiveness of association mapping using cotton germplasm resources.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
Tommasini L Schnurbusch T Fossati D Mascher F Keller B 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2007,115(5):697-708
Association mapping in populations relevant for wheat breeding has a large potential for validating and fine-mapping QTLs
identified in F2- or DH (double haploid)-derived populations. In this study, associations between markers in the region of
QSng.sfr-3BS, a major QTL for resistance to Stagonospora nodorum glume blotch (SNG), and SNG resistance were investigated by linkage and association analyses. After increasing marker density
in 240 F5:7 recombinant inbred lines (RILs), QSng.sfr-3BS explained 43% of the genetic variance and peaked 0.6 cM proximal from the marker SUN2-3B. Association between SNG resistance
and markers mapped in the region of QSng.sfr-3BS was investigated in a population of 44 modern European winter wheat varieties. Two genetically distinct subpopulations were
identified within these lines. In agreement with linkage analyses, association mapping by a least squares general linear model
(GLM) at marker loci in the region of QSng.sfr-3BS revealed the highest association with SNG resistance for SUN2-3B (p < 0.05). Association mapping can provide an effective mean of relating genotypes to complex quantitative phenotypes in hexaploid
wheat. Linkage disequilibrium (r
2) in chromosome 3B extended less than 0.5 cM in 44 varieties, while it extended about 30 cM in 240 RILs, based on 91 SSR and
STS marker-pair comparisons. This indicated that the association mapping population had a marker resolution potential at least
390-fold higher compared to the RIL population.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
Construction of a framework map for Pinus koraiensis Sieb. et Zucc. using SRAP, SSR and ISSR markers
Min-Min Chen Fujuan Feng Xin Sui Mai-He Li Dan Zhao Shijie Han 《Trees - Structure and Function》2010,24(4):685-693
Genetic linkage maps are essential for molecular breeding program. The first genetic linkage map of Pinus koraiensis, using an F1 progeny of 94 individuals, was constructed in the present paper. One hundred and twenty-two molecular markers
were mapped onto 11 linkage groups, 1 triple and 8 pairs at the linkage criteria LOD 4.0. Among these markers, there were
96 sequence-related amplified polymorphism (SRAP) markers, 25 simple sequence repeat (SSR) markers, and 1 inter-simple sequence
repeat (ISSR) marker. The consensus map gained covers 857.464 cM Kosambi (K) with an average marker spacing of 7.03 cM K.
The presented map provides a basis and crucial information for future genomic studies of P. koraiensis, in particular for quantitative trait loci (QTL) mapping of economically important breeding target traits. 相似文献
5.
Newell MA Cook D Tinker NA Jannink JL 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(3):623-632
The level of population structure and the extent of linkage disequilibrium (LD) can have large impacts on the power, resolution,
and design of genome-wide association studies (GWAS) in plants. Until recently, the topics of LD and population structure
have not been explored in oat due to the lack of a high-throughput, high-density marker system. The objectives of this research
were to survey the level of population structure and the extent of LD in oat germplasm and determine their implications for
GWAS. In total, 1,205 lines and 402 diversity array technology (DArT) markers were used to explore population structure. Principal
component analysis and model-based cluster analysis of these data indicated that, for the lines used in this study, relatively
weak population structure exists. To explore LD decay, map distances of 2,225 linked DArT marker pairs were compared with
LD (estimated as r
2). Results showed that LD between linked markers decayed rapidly to r
2 = 0.2 for marker pairs with a map distance of 1.0 centi-Morgan (cM). For GWAS, we suggest a minimum of one marker every cM,
but higher densities of markers should increase marker-QTL association and therefore detection power. Additionally, it was
found that LD was relatively consistent across the majority of germplasm clusters. These findings suggest that GWAS in oat
can include germplasm with diverse origins and backgrounds. The results from this research demonstrate the feasibility of
GWAS and related analyses in oat. 相似文献
6.
QTL mapping by association analysis has recently gained interest in plant breeding research as an alternative to QTL mapping in segregating populations from biparental crosses. In a first experiment on whole-genome association analysis in rapeseed, 684 mapped AFLP markers were tested for association with 14 traits in a set of 84 canola quality winter rapeseed cultivars. For association analysis a general linear model was used. By testing significance of marker-trait associations against a false discovery rate of 0.2, between 1 and 34 associated markers were found for 10 of the 14 traits. Taking into account linkage disequilibrium between the significant markers, these markers represent between 1 and 22 putative QTL for the respective traits. The minimum phenotypic variance explained by the QTL for the different traits ranged from 15% to 53%. A subset of 27 markers were significantly associated with two or more traits. These markers were predominantly shared between traits that were significantly correlated at the phenotypic level. The results show clearly that in rapeseed, QTL mapping by association analysis is a viable alternative to QTL mapping in segregating populations. 相似文献
7.
Zheng Liu Joe Hammerlindl Wilf Keller Peter B. E. McVetty Fouad Daayf Carlos F. Quiros Genyi Li 《Molecular breeding : new strategies in plant improvement》2011,27(4):467-478
Methylthioalkylmalate (MAM) synthases and their associated genes that have been extensively investigated in Arabidopsis control the side-chain elongation of methionine during the synthesis of aliphatic glucosinolates. A Brassica homolog of the Arabidopsis
MAM genes was used in this study to analyze the role of MAM genes in B. napus through RNA interference (RNAi). The silencing of the MAM gene family in B. napus canola and B. napus rapeseed resulted in the reduction of aliphatic glucosinolates and total glucosinolate content. The results indicated that
RNAi has potential for reducing glucosinolate content and improving meal quality in B. napus canola and rapeseed cultivars. Interestingly, MAM gene silencing in B. napus significantly induced the production of 2-propenyl glucosinolate, a 3-carbon side-chain glucosinolate commonly found in B. juncea mustard. Most transgenic plants displayed induction of 2-propenyl glucosinolate; however, the absolute content of this glucosinolate
in transgenic B. napus canola was relatively low (less than 1.00 μmol g−1 seed). In the high glucosinolate content progenies derived from the crosses of B. napus rapeseed and transgenic B. napus canola, MAM gene silencing strongly induced the production of 2-propenyl glucosinolate to high levels (up to 4.45 μmol g−1 seed). 相似文献
8.
Long Y Wang Z Sun Z Fernando DW McVetty PB Li G 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(6):1223-1231
Blackleg resistant cultivars have been developed through conventional breeding methods and are successfully used globally
to control this disease in canola production. To clone blackleg resistance genes and to understand the mechanism underlying
the resistance, a blackleg resistant canola cultivar ‘Surpass 400’ was used to develop a gene mapping population. A previously
reported high density genetic map was used to find a resistance gene region that corresponded to linkage group N10 in B. napus. Differential interactions between the resistant lines and a pathogen isolate were discovered with two resistance genes BLMR1 and BLMR2 identified through linkage analysis of five genome-specific molecular markers. BLMR1 provides resistance through the hypersensitive response that protects inoculated cotyledons from becoming infected, Unlike
BLMR1, BLMR2 slows down the development of individual infection loci. BLMR1 and BLMR2 segregated independently in two large F3BC2 populations. Fine mapping of BLMR1 was performed with 12 genome-specific molecular markers. The closest marker with a genetic distance of 0.13 cM to BLMR1 was identified, which lays a solid foundation for cloning BLMR1. 相似文献
9.
Sujatha Mulpuri Zhao Liu Jiuhuan Feng Thomas J. Gulya Chao-Chien Jan 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,119(5):795-803
The inheritance of resistance to sunflower downy mildew (SDM) derived from HA-R5 conferring resistance to nine races of the
pathogen has been determined and the new source has been designated as Pl
13
. The F2 individuals and F3 families of the cross HA-R5 (resistant) × HA 821 (susceptible) were screened against the four predominant SDM races 300,
700, 730, and 770 in separate tests which indicated dominant control by a single locus or a cluster of tightly linked genes.
Bulked segregant analysis (BSA) was carried out on 116 F2 individuals with 500 SSR primer pairs that resulted in the identification of 10 SSR markers of linkage groups 1 (9 markers)
and 10 (1 marker) of the genetic map (Tang et al. in Theor Appl Genet 105:1124–1136, 2002) that distinguished the bulks. Of these, the SSR marker ORS 1008 of linkage group 10 was tightly linked (0.9 cM) to the Pl
13
gene. Genotyping the F2 population and linkage analysis with 20 polymorphic primer pairs located on linkage group 10 failed to show linkage of the
markers with downy mildew resistance and the ORS 1008 marker. Nevertheless, validation of polymorphic SSR markers of linkage
group 1 along with six RFLP-based STS markers of linkage group 12 of the RFLP map of Jan et al. (Theor Appl Genet 96:15–22,
1998) corresponding to linkage group 1 of the SSR map, mapped seven SSR markers (ORS 965-1, ORS 965-2, ORS 959, ORS 371, ORS 716,
and ORS 605) including ORS 1008 and one STS marker (STS10D6) to linkage group 1 covering a genetic distance of 65.0 cM. The
Pl
13
gene, as a different source with its location on linkage group 1, was flanked by ORS 1008 on one side at a distance of 0.9 cM
and ORS 965-1 on another side at a distance of 5.8 cM. These closely linked markers to the Pl
13
gene provide a valuable basis for marker-assisted selection in sunflower breeding programs. 相似文献
10.
Hou GY Yuan ZR Zhou HL Zhang LP Li JY Gao X Wang DJ Gao HJ Xu SZ 《Molecular biology reports》2011,38(7):4705-4708
Thyroid hormones play an important role in regulating metabolism and can affect homeostasis of fat deposition. The gene encoding
thyroglobulin (TG), producing the precursor for thyroid hormones, has been proposed as a positional and functional candidate
gene for a QTL with an effect on fat deposition. In the present study, we identified 6 novel SNPs at the 3′ flanking region
of the TG gene. The SNP marker association analysis indicated that the T354C, G392A, A430G and T433G SNP markers were significantly
associated with marbling score (P < 0.05). Animals with the new homozygote genotype had higher marbling score than those with the other genotypes. Otherwise,
the linkage disequilibrium analysis indicated that these four SNPs were completely linked (r
2 = 1). Results from this study suggest that TG gene-specific SNP may be a useful marker for meat quality traits in future
marker assisted selection programs in beef cattle. 相似文献
11.
M. C. Moretzsohn C. D. M. Nunes M. E. Ferreira D. Grattapaglia 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(1):63-70
Shell thickness is an important trait in oil palm breeding programs and is the basis for the classification of the varieties
of oil palm into the types dura, tenera and pisifera. This trait seems to be controlled by a single locus, with two alleles
(sh
+ and sh
−) showing codominant expression. Two single-tree linkage maps were constructed for a maternal tenera (sh
+
sh
−) palm and for a paternal pisifera (sh
−
sh
−) palm using the pseudo-testcross mapping strategy in combination with RAPD markers through the analysis of an F1 tenera×pisifera progeny. A total of 308 arbitrary primers were screened in a sample of eight F1 plants and 121 markers were detected in a testcross configuration. An average of 1.66 polymorphic marker per selected primer
were identified in this cross. At LOD 5.0 (with some few exceptions) and θ=0.25 the maternal tenera map included a total of
48 markers distributed in 12 linkage groups or pairs of markers (449.3 cM) while the paternal pisifera map included 42 markers
distributed in 15 linkage groups or pairs of markers (399.7 cM). We used RAPD and bulked segregant analysis (BSA) to identify
markers more tightly linked to the sh
+ locus. A total of 174 new primers not previously used in the linkage analysis were screened using bulks of DNA extracted
from plants selected for the contrasting shell-thickness phenotypes. Two RAPD markers (R11–1282 and T19–1046) were identified
to be linked on both sides of the sh
+ locus on linkage group 4. The estimated map distances from sh
+ to R11–1282 and to T19–1046 were 17.5 cM and 23.9 cM, respectively. The results demonstrate the usefulness of RAPD markers
and the pseudo-testcross mapping strategy for developing genetic linkage information, and constitute an important step towards
early marker-assisted selection for shell thickness in oil palm.
Received: 21 February 1999 / Accepted: 29 April 1999 相似文献
12.
Weiwei Wen Hanwei Mei Fangjun Feng Sibin Yu Zhicheng Huang Jinhong Wu Liang Chen Xiaoyan Xu Lijun Luo 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,119(3):459-470
The majority of 170 rice accessions used in this study were diverse landraces or varieties from a putative mini-core collection
of Chinese germplasm along with some widely used parental lines in genetic analysis or breeding (a few from abroad). The population
was genotyped using 84 SSR or InDel markers on chromosome 7 and 48 markers on other chromosomes. The phenotyping of heading
date, plant height and panicle length were carried out in different locations for 2 years. Based on morphological characterization,
distance-based clustering and model-based estimation of marker data, the population showed a predominant structure with two
subpopulations in correspondence with indica and japonica subspecies. The estimation of linkage disequilibrium in 2 Mb windows varied along chromosome 7 and showed parallel changes
with inter-subspecies differentiation of marker loci (Fst). Based on the mixed linear model considering population structure and family relatedness [i.e. the (Q + K) model], one to three associated markers (P ≤ 0.0001) per trait per experiment were scanned out on rice chromosome 7. Most significant loci were repeated for the data
from both field experiments while two loci were associated with two or three traits. Marker-based allelic effects were shown
in a couple of associated markers as examples. The application of association results in breeding program was also discussed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
13.
KYUNG‐HO MA DUK‐HWAN JANG ANUPAM DIXIT JONG‐WOOK CHUNG SOK‐YOUNG LEE JUNG‐RO LEE HEE‐KYOUG KANG SEONG‐MIN KIM YONG‐JIN PARK 《Molecular ecology resources》2007,7(6):1323-1325
The present study reports the development of 30 polymorphic microsatellite markers for zoysiagrass Zoysia japonica Steud. The 30 markers produced a total of 125 alleles with an average of 4.2 alleles per locus. Values for observed and expected heterozygosities ranged from 0.10 to 0.95 and from 0.15 to 0.81, respectively. At significance threshold (P < 0.05), 11 loci deviated from Hardy–Weinberg equilibrium, whereas significant linkage disequilibrium values were observed between 16 pairs of loci. These markers may provide information needed to select genetically diverse parents for developing breeding and mapping populations of zoysiagrass. 相似文献
14.
Zhen-Xia Sha Shi-Chao Xing Chang-Wei Shao Yong-Sheng Tian Xiao-Lin Liao Song-Lin Chen 《Conservation Genetics》2009,10(6):1799-1801
Ladyfish (Elops saurus Linnaeus) is an economically important marine fish species. 76 microsatellite loci were isolated from an enriched genomic library
of Elops saurus. Twelve of these markers were polymorphic in a test population with alleles per locus ranging from three to nine. The number
of observed, expected heterozygosity and polymorphism information content (PIC) per locus in 20 individuals ranged from 0.2000
to 1.0000, 0.1897–0.8846, 0.1769–0.8476, respectively. One markers significantly deviated from Hardy-Weinberg equilibrium
after Bonferroni correction analysis and there was no significant linkage disequilibrium found between pairs of markers. As
a result, 12 microsatellite markers probably should provide sufficient level of genetic diversity to investigate the fine-scale
population structure, stock management and enhancement, genetic linkage map construction and molecular marker-assisted breeding
in Elops saurus Linnaeus. 相似文献
15.
Identification of molecular markers associated with linoleic acid desaturation in Brassica napus 总被引:6,自引:0,他引:6
D. J. Somers K. R. D. Friesen G. Rakow 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,96(6-7):897-903
Linolenic acid is a component of canola oil that is readily oxidized, which results in a reduced frying stability and shelf
life of the oil. The reduction of linolenic acid in canola seed has therefore been an important breeding objective for many
years. The inheritance of linolenic acid concentrations in seed oil is polygenic and is also strongly influenced by the environment.
For these reasons, molecular markers are sought to assist in early and reliable selection of desired low linolenic acid genotypes
in breeding programmes. Molecular markers associated with low linolenic acid loci were identified in a doubled-haploid population
derived from a cross between the Brassica napus lines, ‘Apollo’ (low linolenic)×YN90-1016 (high linolenic) using RAPDs and bulked segregant analysis. A total of 16 markers
were distributed over three linkage groups, which individually accounted for 32%, 14% and 5% of the phenotypic variation in
linolenic acid content. The rapeseed fad3 gene was mapped near the locus controlling 14% of the variation. The mode of inheritance appeared to be additive, and a
QTL analysis showed that collectively the three loci explained 51% of the phenotypic variation within this population. PCR
fragments for low linolenic acid ‘Apollo’ alleles (3% linolenic acid) were identified at all three loci. Simultaneous selection
for low linolenic acid ‘Apollo’ alleles at each locus resulted in a group of DH lines with 4.0% linolenic acid. The use of
these makers in the breeding programme will enhance the breeding of low linolenic acid B. napus cultivars for production in Canada.
Received: 23 September 1997 / Accepted: 21 October 1997 相似文献
16.
James W. Borrone J. Steven Brown Cecile L. Tondo Margarita Mauro-Herrera David N. Kuhn Helen A. Violi Robert T. Sautter Raymond J. Schnell 《Tree Genetics & Genomes》2009,5(4):553-560
Recent enhancement of the pool of known molecular markers for avocado has allowed the construction of the first moderately
dense genetic map for this species. Over 300 SSR markers have been characterized and 163 of these were used to construct a
map from the reciprocal cross of two Florida cultivars 'Simmonds' and 'Tonnage'. One hundred thirty-five primer pairs amplified
163 usable loci with 20 primer pairs amplifying more than one locus. 'Tonnage' was heterozygous for 152 (93%) loci, whereas
'Simmonds' was heterozygous for 64 (39%). Null alleles were identified at several loci. Linkage maps were produced for both
reciprocal crosses and combined to generate a composite linkage map for the F1 population of 715 individuals. The composite map contains 12 linkage groups. Linkage groups ranged in size from 157.3 cM
(LG2) to 2.4 cM (LG12) and the number of loci mapped per group ranged from 29 (LG1) to two (LG12). The total map length was
1,087.4 cM. Only seven markers were observed to have segregation distortion (α ≤ 0.05) across both sub-composite (reciprocal) maps. Phenotypic data from traits of horticultural interest are currently
being collected on this population with the ultimate goal of identifying useful quantitative trait loci and the development
of a marker-assisted selection program. 相似文献
17.
Comparison of Linkage Disequilibrium in Elite European Maize Inbred Lines using AFLP and SSR Markers 总被引:4,自引:0,他引:4
Benjamin Stich Hans P. Maurer Albrecht E. Melchinger Matthias Frisch Martin Heckenberger Jeroen Rouppe van der Voort Johan Peleman Anker P. Sørensen Jochen C. Reif 《Molecular breeding : new strategies in plant improvement》2006,17(3):217-226
Application of association mapping to plant breeding populations has the potential to revolutionize plant genetics. The main
objectives of this study were to (i) investigate the extent and genomic distribution of linkage disequilibrium (LD) between
pairs of amplified fragment length polymorphism (AFLP) markers, (ii) compare these results with those obtained with simple
sequence repeat (SSR) markers, and (iii) compare the usefulness of AFLP and SSR markers for genomewide association mapping
in plant breeding populations. We examined LD in a cross-section of 72 European elite inbred lines genotyped with 452 AFLP
and 93 SSR markers. LD was significant (p < 0.05) for about 15% of the AFLP marker pairs and for about 49% of the SSR marker pairs in each of the two germplasm groups,
flint and dent. In both germplasm groups the ratio of linked to unlinked loci pairs in LD was higher for AFLPs than for SSRs.
The observation of LD due to linkage for both marker types suggested that genome-wide association mapping should be possible
using either AFLPs or SSRs. The results of our study indicated that SSRs should be favored over AFLPs but the opposite applies
to populations with a long history of recombination. 相似文献
18.
Sargent DJ Passey T Surbanovski N Lopez Girona E Kuchta P Davik J Harrison R Passey A Whitehouse AB Simpson DW 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(7):1229-1240
The linkage maps of the cultivated strawberry, Fragaria × ananassa (2n = 8x = 56) that have been reported to date have been developed predominantly from AFLPs, along with supplementation with transferrable
microsatellite (SSR) markers. For the investigation of the inheritance of morphological characters in the cultivated strawberry
and for the development of tools for marker-assisted breeding and selection, it is desirable to populate maps of the genome
with an abundance of transferrable molecular markers such as microsatellites (SSRs) and gene-specific markers. Exploiting
the recent release of the genome sequence of the diploid F. vesca, and the publication of an extensive number of polymorphic SSR markers for the genus Fragaria, we have extended the linkage map of the ‘Redgauntlet’ × ‘Hapil’ (RG × H) mapping population to include a further 330 loci,
generated from 160 primer pairs, to create a linkage map for F. × ananassa containing 549 loci, 490 of which are transferrable SSR or gene-specific markers. The map covers 2140.3 cM in the expected
28 linkage groups for an integrated map (where one group is composed of two separate male and female maps), which represents
an estimated 91% of the cultivated strawberry genome. Despite the relative saturation of the linkage map on the majority of
linkage groups, regions of apparent extensive homozygosity were identified in the genomes of ‘Redgauntlet’ and ‘Hapil’ which
may be indicative of allele fixation during the breeding and selection of modern F. × ananassa cultivars. The genomes of the octoploid and diploid Fragaria are largely collinear, but through comparison of mapped markers on the RG × H linkage map to their positions on the genome
sequence of F. vesca, a number of inversions were identified that may have occurred before the polyploidisation event that led to the evolution
of the modern octoploid strawberry species. 相似文献
19.
Monique Juergens Claudia Paetsch Ilona Krämer Marc Zahn Frank Rabenstein Jörg Schondelmaier Edgar Schliephake Rod Snowdon Wolfgang Friedt Frank Ordon 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,120(4):735-744
The aphid transmitted Turnip yellows virus (TuYV) has become a serious pathogen in many rapeseed (Brassica napus L.) growing areas. Three-years’ field trials were carried out to get detailed information on the genetics of TuYV resistance
derived from the resynthesised B. napus line ‘R54’ and to develop closely linked markers. F1 plants and segregating doubled-haploid (DH) populations derived from crosses to susceptible cultivars were analysed using
artificial inoculation with virus-bearing aphids, followed by DAS-ELISA. Assuming a threshold of E
405 = 0.1 in ELISA carried out in December, the results led to the conclusion that pre-winter inhibition of TuYV is inherited
in a monogenic dominant manner. However, the virus titre in most resistant lines increased during the growing period, indicating
that the resistance is incomplete and that the level of the virus titre is influenced by environmental factors. Bulked-segregant
marker analysis for this resistance locus identified two closely linked SSR markers along with six closely linked and three
co-segregating AFLP markers. Two AFLP markers were converted into co-dominant STS markers, facilitating efficient marker-based
selection for TuYV resistance. Effective markers are particularly valuable with respect to breeding for TuYV resistance, because
artificial inoculation procedures using virus-bearing aphids are extremely difficult to integrate into practical rapeseed
breeding programs. 相似文献
20.
James W. Olmstead Audrey M. Sebolt Antonio Cabrera Suneth S. Sooriyapathirana Sue Hammar Gloria Iriarte Dechun Wang Charles Y. Chen Esther van der Knaap Amy F. Iezzoni 《Tree Genetics & Genomes》2008,4(4):897-910
Linkage maps of the sweet cherry cultivar ‘Emperor Francis’ (EF) and the wild forest cherry ‘New York 54’ (NY) were constructed
using primarily simple sequence repeat (SSR) markers and gene-derived markers with known positions on the Prunus reference map. The success rate for identifying SSR markers that could be placed on either the EF or NY maps was only 26%
due to two factors: a reduced transferability of other Prunus-species-derived markers and a low level of polymorphism in the mapping parents. To increase marker density, we developed
four cleaved amplified polymorphic sequence markers (CAPS), 19 derived CAPS markers, and four insertion–deletion markers for
cherry based on 101 Prunus expressed sequence tags. In addition, four gene-derived markers representing orthologs of a tomato vacuolar invertase and
fruit size gene and two sour cherry sorbitol transporters were developed. To complete the linkage analysis, 61 amplified fragment
length polymorphism and seven sequence-related amplified polymorphism markers were also used for map construction. This analysis
resulted in the expected eight linkage groups for both parents. The EF and NY maps were 711.1 cM and 565.8 cM, respectively,
with the average distance between markers of 4.94 cM and 6.22 cM. A total of 82 shared markers between the EF and NY maps
and the Prunus reference map showed that the majority of the marker orders were the same with the Prunus reference map suggesting that the cherry genome is colinear with that of the other diploid Prunus species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献