共查询到20条相似文献,搜索用时 15 毫秒
1.
R. Bernardo 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(3-4):551-556
Marker-based assortative mating (MAM) – the mating of individuals that have similar genotypes at random marker loci – can
increase selection response for a single trait by 3–8% over random mating (RM). Genetic gain is usually desired for multiple
traits rather than for a single trait. My objectives in this study were to (1) compare MAM, phenotypic assortative mating
(PAM), and RM of selected individuals for improving two traits and (2) determine when MAM will be most useful for improving
two traits. I simulated 20 generations of selecting 32 out of 200 individuals in an F2 population. The individuals were selected based on an index (SI) of two traits and were intermated by MAM, PAM, or RM. I
studied eight genetic models that differed in three contrasts: (1) weight, number of quantitative trait loci (QTL), and heritability
(h
2) for each trait; (2) linkage of QTL for each trait; and (3) trait means of the inbred parents of the F2. For SI and the two component traits, MAM increased short-term selection response by 5–8% in six out of the eight genetic
models. The MAM procedure was least effective in two genetic models, wherein the QTL for one trait were unlinked to the QTL
for the other trait and the parents of the F2 had divergent means for each trait. The loss of QTL heterozygosity was much greater with MAM than with PAM or RM. Consequently,
the advantage of MAM over RM dissipated after 5–7 generations. Differences were small between selection responses with PAM
and RM. The MAM procedure can enhance short-term selection response for two traits when selection is not stringent, h
2 is low, and the means of the parents of the F2 are equal for each trait.
Received: 10 June 1998 / Accepted: 5 August 1998 相似文献
2.
Mapping of QTL associated with chilling tolerance during reproductive growth in soybean 总被引:6,自引:0,他引:6
Funatsuki H Kawaguchi K Matsuba S Sato Y Ishimoto M 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(5):851-861
Low temperatures in summer bring about drastic reduction in seed yield of soybean [Glycine max (L.) Merr.]. To identify quantitative trait loci (QTL) associated with chilling tolerance during the reproductive growth
in soybean, a recombinant inbred line (RIL) population consisting of 104 F6-derived lines was created from a cross between two cultivars, chilling-tolerant Hayahikari and chilling-sensitive Toyomusume.
The RIL were genotyped with 181 molecular and phenotypic markers and were scored with regard to chilling tolerance, which
was evaluated by comparison of seed-yielding abilities in two artificial climatic environments at chilling and usual temperatures.
Three QTL were detected for chilling tolerance in seed-yielding ability. Two of them, qCTTSW1 and qCTTSW2, were mapped near QTL for flowering time, and the latter had an epistatic interaction with a marker locus located near another
QTL for flowering time, where no significant QTL for chilling tolerance was detected. The analysis of an F2 population derived from the cross between Hayahikari and an RIL of the Hayahikari genotype at all QTL for flowering time
confirmed the effect of the third QTL, qCTTSW3, on chilling tolerance and suggested that qCTTSW1 was basically independent of the QTL for flowering time. The findings and QTL found in this study may provide useful information
for marker-assisted selection (MAS) and further genetic studies on soybean chilling tolerance. 相似文献
3.
Jonathan H. Clarke Richard Mithen James K. M. Brown Caroline Dean 《Molecular & general genetics : MGG》1995,248(3):278-286
Quantitative trait loci (QTL) analyses based on restriction fragment length polymorphism maps have been used to resolve the genetic control of flowering time in a cross between twoArabidopsis thaliana ecotypes H51 and Landsbergerecta, differing widely in flowering time. Five quantitative trait loci affecting flowering time were identified in this cross (RLN1-5), four of which are located in regions containing mutations or loci previously identified as conferring a late-flowering phenotype. One of these loci is coincident with theFRI locus identified as the major determinant for late flowering and vernalization responsiveness in theArabidopsis ecotype Stockholm.RLN5, which maps to the lower half of chromosome five (between markers mi69 and m233), only affected flowering time significantly under short day conditions following a vernalization period. The late-flowering phenotype of H51 compared to Landsbergerecta was due to alleles conferring late flowering at only two of the five loci. At the three other loci, H51 possessed alleles conferring early flowering in comparison to those of Landsbergerecta. Combinations of alleles conferring early and late flowering from both parents accounted for the transgressive segregation of flowering time observed within the F2 population. Three QTL,RLN1,RLN2 andRLN3 displayed significant genotype-by-environment interactions for flowering time. A significant interaction between alleles atRLN3 andRLN4 was detected. 相似文献
4.
Genomic selection in forest tree breeding 总被引:2,自引:0,他引:2
Genomic selection (GS) involves selection decisions based on genomic breeding values estimated as the sum of the effects of
genome-wide markers capturing most quantitative trait loci (QTL) for the target trait(s). GS is revolutionizing breeding practice
in domestic animals. The same approach and concepts can be readily applied to forest tree breeding where long generation times
and late expressing complex traits are also a challenge. GS in forest trees would have additional advantages: large training
populations can be easily assembled and accurately phenotyped for several traits, and the extent of linkage disequilibrium
(LD) can be high in elite populations with small effective population size (N
e) frequently used in advanced forest tree breeding programs. Deterministic equations were used to assess the impact of LD
(modeled by N
e and intermarker distance), the size of the training set, trait heritability, and the number of QTL on the predicted accuracy
of GS. Results indicate that GS has the potential to radically improve the efficiency of tree breeding. The benchmark accuracy
of conventional BLUP selection is reached by GS even at a marker density ~2 markers/cM when N
e ≤ 30, while up to 20 markers/cM are necessary for larger N
e. Shortening the breeding cycle by 50% with GS provides an increase ≥100% in selection efficiency. With the rapid technological
advances and declining costs of genotyping, our cautiously optimistic outlook is that GS has great potential to accelerate
tree breeding. However, further simulation studies and proof-of-concept experiments of GS are needed before recommending it
for operational implementation. 相似文献
5.
Adaptive divergence in flowering time among natural populations of Arabidopsis thaliana: Estimates of selection and QTL mapping
下载免费PDF全文
![点击此处可从《Evolution; international journal of organic evolution》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jon Ågren Christopher G. Oakley Sverre Lundemo Douglas W. Schemske 《Evolution; international journal of organic evolution》2017,71(3):550-564
To identify the ecological and genetic mechanisms of local adaptation requires estimating selection on traits, identifying their genetic basis, and evaluating whether divergence in adaptive traits is due to conditional neutrality or genetic trade‐offs. To this end, we conducted field experiments for three years using recombinant inbred lines (RILs) derived from two ecotypes of Arabidopsis thaliana (Italy, Sweden), and at each parental site examined selection on flowering time and mapped quantitative trait loci (QTL). There was strong selection for early flowering in Italy, but weak selection in Sweden. Eleven distinct flowering time QTL were detected, and for each the Italian genotype caused earlier flowering. Twenty‐seven candidate genes were identified, two of which (FLC and VIN3) appear under major flowering time QTL in Italy. Seven of eight QTL in Italy with narrow credible intervals colocalized with previously reported fitness QTL, in comparison to three of four in Sweden. The results demonstrate that the magnitude of selection on flowering time differs strikingly between our study populations, that the genetic basis of flowering time variation is multigenic with some QTL of large effect, and suggest that divergence in flowering time between ecotypes is due mainly to conditional neutrality. 相似文献
6.
Phillip A. Wadl Arnold M. Saxton Xinwang Wang Vince R. Pantalone Timothy A. Rinehart Robert N. Trigiano 《Molecular breeding : new strategies in plant improvement》2011,27(3):409-416
The objective of our investigation was to acquire information on the association between molecular markers and foliage color
in flowering dogwood in order to improve our understanding of the inheritance of this trait and to make possible early selection
of red foliage genotypes in breeding programs. A segregating pseudo-F2 population of 94 individuals of flowering dogwood (Cornus florida L.), together with 255 simple sequence repeat markers, was used to identify putative quantitative trait loci (QTL) for foliage
color. Foliage color segregated into green- and red-leaved phenotypes and was visually rated for color on five spring dates
over 3 years (2007–2009). Repeated measures single-marker categorical analysis of variance (ANOVA) identified four putative
QTL (CF309C, CF792A, CF367B, and CF367C) on three linkage groups. Single-marker categorical ANOVA was then used to determine
stability of QTL across dates. We identified different QTL, found a low percentage of phenotypic variance explained by the
QTL, and detected QTL instability over time, providing evidence of the complex genetics for red pigment expression in flowering
dogwood. 相似文献
7.
Fan Z Robbins MD Staub JE 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(5):843-855
Cucumber (Cucumis sativus L.; 2n=2x=14) has a narrow genetic base, and commercial yield of US processing cucumber has plateaued in the last 15 years. Yield may
be increased by altering plant architecture to produce unique early flowering (days to flower, DTF), female (gynoecious, GYN),
highly branched (multiple lateral branching, MLB), long-fruited (length:diameter ratio, L:D) cultivars with diverse plant
statures. The genetic map position of QTL conditioning these quantitatively inherited yield component traits is known, and
linked molecular markers may have utility in marker-assisted selection (MAS) programs to increase selection efficiency, and
effectiveness. Therefore, a base population (C0), created by intermating four unique but complementary lines, was subjected to three cycles (C1–C3) of phenotypic (PHE) mass selection for DTF, GYN, MLB, and L:D. In tandem, two cycles of marker-assisted backcrossing for
these traits began with selected C2 progeny (C2S) to produce families (F1[i.e., C2S × C2S], and BC1 [i.e., F1 × C2S]) for line extraction, and for comparative analysis of gain from selection by PHE selection, and MAS. Frequencies of marker
loci were used to monitor selection-dependent changes during PHE selection, and MAS. Similar gain from selection was detected
as a result of PHE selection, and MAS for MLB (~0.3 branches/cycle), and L:D (~0.1 unit increase/cycle) with concomitant changes
in frequency at linked marker loci. Although genetic gain was not realized for GYN during PHE selection, the percentage of
female flowers of plants subjected to MAS was increased (5.6–9.8% per cycle) depending upon the BC1 population examined. Selection-dependent changes in frequency were also detected at marker loci linked to female sex expression
during MAS. MAS operated to fix favorable alleles that were not exploited by PHE selection in this population, indicating
that MAS could be applied for altering plant architecture in cucumber to improve its yield potential.
The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper
therefore must be hereby, marked advertisement solely to indicate this fact. Mention of a trade name, proprietary product,
or specific equipment does not constitute a guarantee or warranty by the USDA and does not imply its approval to the exclusion
of other products that may be suitable. 相似文献
8.
A model for marker-assisted selection among single crosses with multiple genetic markers 总被引:3,自引:0,他引:3
R. Bernardo 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(3):473-478
Trait means of marker genotypes are often inconsistent across experiments, thereby hindering the use of regression techniques
in marker-assisted selection. Best linear unbiased prediction based on trait and marker data (TM-BLUP) does not require prior
information on the mean effects associated with specific marker genotypes and, consequently, may be useful in applied breeding
programs. The objective of this paper is to present a flanking-marker, TM-BLUP model that is applicable to interpopulation
single crosses that characterize maize (Zea mays L.) breeding programs. The performance of a single cross is modeled as the sum of testcross additive and dominance effects
at unmarked quantitative trait loci (QTL) and at marked QTL (MQTL). The TM-BLUP model requires information on the recombination
frequencies between flanking markers and the MQTL and on MQTL variances. A tabular method is presented for calculating the
conditional probability that MQTL alleles in two inbreds are identical by descent given the observed marker genotypes (G
k
obs) at the kth MQTL. Information on identity by descent of MQTL alleles can then be used to calculate the conditional covariance
of MQTL effects between single crosses given G
k
obs. The inverse of the covariance matrix for dominance effects at unmarked QTL and MQTL can be written directly from the inverse
of the covariance matrices of the corresponding testcross additive effects. In practice, the computations required in TM-BLUP
may be prohibitive. The computational requirements may be reduced with simplified TM-BLUP models wherein dominance effects
at MQTL are excluded, only the single crosses that have been tested are included, or information is pooled across several
MQTL.
Received: 22 June 1997 / Accepted: 25 February 1998 相似文献
9.
M. Bohn S. Groh M. M. Khairallah D. A. Hoisington H. F. Utz A. E. Melchinger 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2001,103(6-7):1059-1067
Cross validation (CV) and validation with an independent sample (IV) are new biometric approaches in QTL analysis to obtain
unbiased estimates of QTL effects and the proportion of the genetic variance explained by the detected marker-QTL association
(p). Our objective with these methods was to obtain a realistic picture on the prospects of marker-assisted selection (MAS)
for improving the resistance of maize against the tropical stem borer species Diatraea grandiosella (SWCB) and Diatraea saccharalis (SCB). Published QTL mapping studies on leaf-damage ratings (LDR) with populations of F2:3 lines and recombinant inbred lines (RIL) from crosses CML131×CML67 and Ki3× CML139 of tropical maize inbreds were re-analyzed
with CV and IV. With CV, the reduction in p for LDR compared to p obtained with the whole data set varied between 41.0 and 79.6% in the populations of F2:3 lines and between 30.1 and 65.2% in the two populations of RIL. Estimates of p for SCB LDR were similar for CV and IV. For SWCB LDR, p estimates obtained with IV were larger than those obtained with CV in CML131× CML67. The reverse was observed for Ki3×CML139.
Under the assumption of identical selection intensities, and based on the re-estimates of p, MAS using only molecular marker information is less-efficient than conventional phenotypic selection (CPS). MAS combining
marker and phenotypic data increases the relative efficiency by only 4% in comparison to CPS. In conclusion, MAS for improving
SWCB and SCB LDR seems not-promising unless additional QTLs with proven large effects are available or the costs of marker
assays are considerably reduced.
Received: 7 December 2000 / Accepted: 5 February 2001 相似文献
10.
Huaan Yang Daniel Renshaw Geoff Thomas Bevan Buirchell Mark Sweetingham 《Molecular breeding : new strategies in plant improvement》2008,21(4):473-483
A key challenge in marker-assisted selection (MAS) for molecular plant breeding is to develop markers linked to genes of interest
which are applicable to multiple breeding populations. In this study representative F2 plants from a cross Mandalup (resistant to anthracnose disease) × Quilinock (susceptible) of Lupinus angustifolius were used in DNA fingerprinting by Microsatellite-anchored Fragment Length Polymorphism (MFLP). Nine candidate MFLP markers
linked to anthracnose resistance were identified, then ‘validated’ on 17 commercial cultivars. The number of “false positives”
(showing resistant-allele band but lack of the R gene) for each of the nine candidate MFLP markers on the 17 cultivars ranged
from 1 to 9. The candidate marker with least number of false positive was selected, sequenced, and was converted into a co-dominant,
sequence-specific, simple PCR based marker suitable for routine implementation. Testing on 180 F2 plants confirmed that the converted marker was linked to the R gene at 5.1 centiMorgan. The banding pattern of the converted
marker was consistent with the disease phenotype on 23 out of the 24 cultivars. This marker, designated “AnManM1”, is now
being used for MAS in the Australian lupin breeding program. We conclude that generation of multiple candidate markers, followed
by a validation step to select the best marker before conversion to an implementable form is an efficient strategy to ensure
wide applicability for MAS. 相似文献
11.
Molecular breeding for grain yield in barley: an evaluation of QTL effects in a spring barley cross 总被引:8,自引:0,他引:8
H. Zhu G. Briceño R. Dovel P. M. Hayes B. H. Liu C. T. Liu S. E. Ullrich 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(5):772-779
We report results from a breeding strategy designed to accumulate favorable QTL alleles for grain yield identified in the
SteptoeבMorex’ (SM) barley germplasm. Two map lines (SM73 and SM145) from the original mapping population were selected based
on their marker genotype and QTL structure. When crossed, these lines would be expected to produce progeny with most favorable
QTL alleles. One hundred doubled haploid (DH) lines from the F1 hybrid of this cross were genotyped with ten RFLP markers and one morphological marker defining grain yield to monitor QTL
segregation. A subset of 24 lines representing various combinations of putatively favorable and unfavorable QTL alleles, together
with Steptoe, ‘Morex’, SM73, and SM145, were phenotyped for grain yield in five environments. Multiple regression procedures
were used to explore phenotype and genotype relationships. Most target QTLs showed significant effects. However, significance
and magnitude of QTL effects and favorable QTL allele phase varied across environments. All target QTLs showed significant
QTL-by-environment interaction (QTL×E), and the QTL on chromosome 2 expressed alternative favorable QTL alleles in different
environments. Digenic epistatic effects were also detected between some QTL loci. For traits such as grain yield, marker-assisted
selection efforts may be better targeted at determining optimum combinations of QTL alleles rather than pyramiding alleles
detected in a reference mapping population.
Received: 2 June 1998 / Accepted: 17 September 1998 相似文献
12.
Jonathan H. Clarke Richard Mithen James K. M. Brown Caroline Dean 《Molecular genetics and genomics : MGG》1995,248(3):278-286
Quantitative trait loci (QTL) analyses based on restriction fragment length polymorphism maps have been used to resolve the genetic control of flowering time in a cross between twoArabidopsis thaliana ecotypes H51 and Landsbergerecta, differing widely in flowering time. Five quantitative trait loci affecting flowering time were identified in this cross (RLN1-5), four of which are located in regions containing mutations or loci previously identified as conferring a late-flowering phenotype. One of these loci is coincident with theFRI locus identified as the major determinant for late flowering and vernalization responsiveness in theArabidopsis ecotype Stockholm.RLN5, which maps to the lower half of chromosome five (between markers mi69 and m233), only affected flowering time significantly under short day conditions following a vernalization period. The late-flowering phenotype of H51 compared to Landsbergerecta was due to alleles conferring late flowering at only two of the five loci. At the three other loci, H51 possessed alleles conferring early flowering in comparison to those of Landsbergerecta. Combinations of alleles conferring early and late flowering from both parents accounted for the transgressive segregation of flowering time observed within the F2 population. Three QTL,RLN1,RLN2 andRLN3 displayed significant genotype-by-environment interactions for flowering time. A significant interaction between alleles atRLN3 andRLN4 was detected. 相似文献
13.
S. Doganlar S. D. Tanksley M. A. Mutschler 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(2):249-255
Using RAPD marker analysis, two quantitative trait loci (QTLs) associated with earliness due to reduced fruit-ripening time
(days from anthesis to ripening = DTR) were identified and mapped in an F2 population derived from a cross between Lycopersicon esculentum’E6203’ (normal ripening) and Lycopersicon esculentum’Early Cherry’ (early ripening). One QTL, on chromosome 5, was associated with a reduction in both ripening time (5 days)
and fruit weight (29.3%) and explained 15.8 and 13% of the total phenotypic variation for DTR and fruit weight, respectively.
The other QTL, on chromosome 12, was primarily associated with a reduction only in ripening time (7 days) and explained 12.3%
of the total phenotypic variation for DTR. The gene action at this QTL was found to be partially dominant (d/a=0.41). Together,
these two QTLs explained 25.1% of the total phenotypic variation for DTR. Additionally, two QTLs associated with fruit weight
were identified in the same F2 population and mapped to chromosomes 4 and 6, respectively. Together, these two QTLs explained 30.9% of the total phenotypc
variation for fruit weight. For all QTLs, the ’Early Cherry’ alleles caused reductions in both ripening time and fruit weight.
The polymorphic band for the most significant RAPD marker (OPAB-06), linked to the reduced ripening time QTL on chromosome
12, was converted to a cleaved amplified polymorphism (CAP) assay for marker-aided selection and further introgression of
early ripening time (DTR) into cultivated tomato.
Received: 15 March 1999 / Accepted: 29 April 1999 相似文献
14.
José Antonio Campoy David Ruiz José Egea David Jasper G. Rees Jean Marc Celton Pedro Martínez-Gómez 《Plant Molecular Biology Reporter》2011,29(2):404-410
Time of flowering was studied during 3 years in a BC1 apricot progeny of 73 seedlings derived from a cross between the F1
selection “Z506-07” (“Orange Red” × “Currot”) and the Spanish cultivar “Currot”. Results indicated a quantitative inheritance
of flowering time in apricot with an influence of juvenility and environmental conditions (chill accumulation) on the evaluation
and expression of this trait. Genetic maps consisting of 11 linkage groups for both parents representing the eight chromosomes
of apricot were developed using 46 apricot and peach simple sequence repeat (SSR-microsatellites) markers and were used for
the identification of quantitative trait loci (QTL). QTL analysis for flowering time allowed the identification of one significant
QTL on the linkage group 5 (G5) of “Z506-07”, and explaining most of the phenotypic variation. Two microsatellite loci (UDAp-423r
and AMPA-105) were found to be tightly linked to this important agronomic trait. Finally, we discuss the stability of the
QTL described during the 3 years of the study and the development of efficient marker-assisted selection strategies applied
to apricot and other Prunus breeding programs. 相似文献
15.
Thomas Mitchell-Olds 《Evolution; international journal of organic evolution》1996,50(1):140-145
We have mapped genes causing life-history trade-offs, and they behave as predicted by ecological theory. Energetic and quantitative-genetic models suggest a trade-off between age and size at first reproduction. Natural selection favored plants that flower early and attain large size at first reproduction. Response to selection was opposed by a genetic trade-off between these two components of fitness. Two quantitative-trait loci (QTLs) influencing flowering time were mapped in a recombinant inbred population of Arabidopsis. These QTLs also influenced size at first reproduction, but did not affect growth rate (resource acquisition). Substitutions of small chromosomal segments, which may represent allelic differences at flowering time loci, caused genetic trade-offs between life-history components. One QTL explained 22% of the genetic variation in flowering time. It is within a few centiMorgans (cM) of the gigantea (GI) locus, and may be allelic with GI. Sixteen percent of the genetic variation was explained by another QTL, FDR1, near 18 cM on chromosome II, which does not correspond to any previously identified flowering-time locus. These life-history genes regulate patterns of resource allocation and life-history trade-offs in this population. 相似文献
16.
Validated quantitative trait loci for eggshell quality in experimental and commercial laying hens
下载免费PDF全文
![点击此处可从《Animal genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M. Tuiskula‐Haavisto M. Honkatukia I. C. Dunn M. M. Bain D. J. De Koning R. Preisinger M. Schmutz J. Arango D. Fischer J. Vilkki 《Animal genetics》2018,49(4):329-333
Compromised eggshell quality causes considerable economic losses for the egg industry. Breeding for improved eggshell quality has been very challenging. Eggshell quality is a trait that would greatly benefit from marker‐assisted selection, which would allow the selection of sires for their direct contribution to the trait and would also allow implementation of measurements integrating a number of shell parameters that are difficult to measure. In this study, we selected the most promising autosomal quantitative trait loci (QTL) affecting eggshell quality on chromosomes 2, 3, 6 and 14 from earlier experiments and we extended the F2 population to include 1599 F2 females. The study was repeated on two commercial populations: Lohmann Tierzucht Rhode Island Red line (n = 692 females) and a Hy‐Line White Plymouth Rock line (n = 290 progeny tested males). We analyzed the selected autosomal QTL regions on the three populations with SNP markers at 4–13 SNPs/Mb density. QTL for eggshell quality were replicated on all studied regions in the F2 population. New QTL were detected for eggshell color on chromosomes 3 and 6. Marker associations with eggshell quality traits were validated in the tested commercial lines on chromosomes 2, 3 and 6, thus paving the way for marker‐assisted selection for improved eggshell quality. 相似文献
17.
18.
F. Taguchi-Shiobara S. Y. Lin K. Tanno T. Komatsuda M. Yano T. Sasaki S. Oka 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,95(5-6):828-833
Quantitative trait loci (QTL) controlling the regeneration ability of rice seed callus were detected using 245 RFLP markers
and 98 BC1F5 lines derived from two varieties, ‘Nipponbare’ and ‘Kasalath’. Regeneration ability was evaluated by two indices: average
number of regenerated shoots per callus (NRS) and regeneration rate (RR). The BC1F5 lines showed continuous segregation for both indices. Five putative QTL for NRS (tentatively named qRg1, qRg2, qRg4a, qRg4b and qRg4c) located on chromosomes 1, 2 and 4 were detected. Digenic interaction among these detected QTL was not significant (P<0.01). Among the five QTL detected, four ‘Kasalath’ alleles and one ‘Nipponbare’ allele increased NRS. According to an estimate
based on the nearest marker loci, the five QTL accounted for 38.5% of the total phenotypic variation of the BC1F5 lines. For RR, four putative QTL were detected on chromosomes 2 and 4, and all of these were in the same chromosomal regions
as the NRS QTL. The four RR QTL accounted for 32.6% of the total phenotypic variation.
Received: 7 November 1996 / Accepted: 25 April 1997 相似文献
19.
V. Martinez P. Dettleff P. Lopez G. Fernandez A. Jedlicki J. M. Yañez W. S. Davidson 《Animal genetics》2013,44(2):223-226
Relatively large rates of response to traits of economic importance have been observed in different selection experiments in salmon. Several QTL have been mapped in the salmon genome, explaining unprecedented levels of phenotypic variation. Owing to the relatively large selection intensity, individual loci may be indirectly selected, leaving molecular footprints of selection, together with increased inbreeding, as its likely relatives will share the selected loci. We used population differentiation and levels of linkage disequilibrium in chromosomes known to be harbouring QTL for body weight, infectious pancreatic necrosis resistance and infectious salmon anaemia resistance to assess the recent selection history at the genomic level in Atlantic salmon. The results clearly suggest that the marker SSA0343BSFU on chromosome 3 (body weight QTL) showed strong evidence of directional selection. It is intriguing that this marker is physically mapped to a region near the coding sequence of DVL2 , making it an ideal candidate gene to explain the rapid evolutionary response of this chromosome to selection for growth in Salmo salar. Weak evidence of diversifying selection was observed in the QTL associated with infectious pancreatic necrosis and infectious salmon anaemia resistance. Overall, this study showed that artificial selection has produced important changes in the Atlantic salmon genome, validating QTL in commercial salmon populations used for production purposes according to the recent selection history. 相似文献
20.
QTL-seq identifies an early flowering QTL located near Flowering Locus T in cucumber 总被引:1,自引:0,他引:1
Hongfeng Lu Tao Lin Joël Klein Shenhao Wang Jianjian Qi Qian Zhou Jinjing Sun Zhonghua Zhang Yiqun Weng Sanwen Huang 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2014,127(7):1491-1499