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1.
Flavie Tortereau Hélène Gilbert Henri CM Heuven Jean-Pierre Bidanel Martien AM Groenen Juliette Riquet 《遗传、选种与进化》2011,43(1):11
Background
In the pig, multiple QTL associated with growth and fatness traits have been mapped to chromosome 2 (SSC2) and among these, at least one shows paternal expression due to the IGF2-intron3-G3072A substitution. Previously published results on the position and imprinting status of this QTL disagree between analyses from French and Dutch F2 crossbred pig populations obtained with the same breeds (Meishan crossed with Large White or Landrace).Methods
To study the role of paternal and maternal alleles at the IGF2 locus and to test the hypothesis of a second QTL affecting backfat thickness on the short arm of SSC2 (SSC2p), a QTL mapping analysis was carried out on a combined pedigree including both the French and Dutch F2 populations, on the progeny of F1 males that were heterozygous (A/G) and homozygous (G/G) at the IGF2 locus. Simulations were performed to clarify the relations between the two QTL and to understand to what extent they can explain the discrepancies previously reported.Results
The QTL analyses showed the segregation of at least two QTL on chromosome 2 in both pedigrees, i.e. the IGF2 locus and a second QTL segregating at least in the G/G F1 males and located between positions 30 and 51 cM. Statistical analyses highlighted that the maternally inherited allele at the IGF2 locus had a significant effect but simulation studies showed that this is probably a spurious effect due to the segregation of the second QTL.Conclusions
Our results show that two QTL on SSC2p affect backfat thickness. Differences in the pedigree structures and in the number of heterozygous females at the IGF2 locus result in different imprinting statuses in the two pedigrees studied. The spurious effect observed when a maternally allele is present at the IGF2 locus, is in fact due to the presence of a second closely located QTL. This work confirms that pig chromosome 2 is a major region associated with fattening traits. 相似文献2.
Bala R. Thumma Simon G. Southerton John C. Bell John V. Owen Martin L. Henery Gavin F. Moran 《Tree Genetics & Genomes》2010,6(2):305-317
To identify the chromosomal regions affecting wood quality traits, we conducted a genome-wide quantitative trait locus (QTL)
analysis of wood quality traits in Eucalyptus nitens. This information is important to exploit the full potential of the impending Eucalyptus genome sequence. A three generational mapping population consisting of 296 progeny trees was used to identify QTL associated
with several wood quality traits in E. nitens. Thirty-six QTL positions for cellulose content, pulp yield, lignin content, density, and microfibril angle (MFA) were identified
across different linkage groups. On linkage groups (LG)2 and 8, cellulose QTL cluster with pulp yield and extractives QTL
while on LG4 and 10 cellulose and pulp yield QTLs cluster together. Similarly, on LG4, 5, and 6 QTL for lignin traits were
clustered together. At two positions, QTL for MFA, a physical trait related to wood stiffness, were clustered with QTL for
lignin traits. Several cell wall candidate genes were co-located to QTL positions affecting different traits. Comparative
QTL analysis with Eucalyptus globulus revealed two common QTL regions for cellulose and pulp yield. The QTL positions identified in this study provide a resource
for identifying wood quality genes using the impending Eucalyptus genome sequence. Candidate genes identified in this study through co-location to QTL regions may be useful in association
studies. 相似文献
3.
Jules S. Freeman Simon P. Whittock Brad M. Potts René E. Vaillancourt 《Tree Genetics & Genomes》2009,5(4):713-722
Regions of the genome affecting physical and chemical wood properties (quantitative trait loci (QTL)), as well as growth,
were identified using a clonally replicated, outbred F2 family (112 genotypes, each with two ramets) of Eucalyptus globulus, planted in a field trial in north-west Tasmania. Traits studied were growth (assessed by stem diameter), wood density, cellulose
content, pulp yield and lignin content. These traits are important in breeding for pulpwood, and will be important in breeding
for carbon sequestration and biofuel production. Between one and four QTL were located for each trait, with each QTL explaining
between 4% and 12% of the phenotypic variation. Several QTL for chemical wood properties were co-located, consistent with
their high phenotypic correlations, and may reflect pleiotropic effects of the same genes. In contrast, QTL for density and
lignin content with overlapping confidence intervals were considered to be due to independent genes, since the QTL effects
were inherited from different parents. The inclusion of fully informative microsatellites on the linkage map allowed the determination
of homology at the linkage group level between QTL and candidate genes in different pedigrees of E. globulus and different eucalypt species. None of the candidate genes mapped in comparable studies co-located with our major QTL for
wood chemical properties, arguing that there are important candidate genes yet to be discovered. 相似文献
4.
A consensus linkage map for sugi (Cryptomeria japonica) from two pedigrees, based on microsatellites and expressed sequence tags 总被引:3,自引:0,他引:3
Tani N Takahashi T Iwata H Mukai Y Ujino-Ihara T Matsumoto A Yoshimura K Yoshimaru H Murai M Nagasaka K Tsumura Y 《Genetics》2003,165(3):1551-1568
A consensus map for sugi (Cryptomeria japonica) was constructed by integrating linkage data from two unrelated third-generation pedigrees, one derived from a full-sib cross and the other by self-pollination of F1 individuals. The progeny segregation data of the first pedigree were derived from cleaved amplified polymorphic sequences, microsatellites, restriction fragment length polymorphisms, and single nucleotide polymorphisms. The data of the second pedigree were derived from cleaved amplified polymorphic sequences, isozyme markers, morphological traits, random amplified polymorphic DNA markers, and restriction fragment length polymorphisms. Linkage analyses were done for the first pedigree with JoinMap 3.0, using its parameter set for progeny derived by cross-pollination, and for the second pedigree with the parameter set for progeny derived from selfing of F1 individuals. The 11 chromosomes of C. japonica are represented in the consensus map. A total of 438 markers were assigned to 11 large linkage groups, 1 small linkage group, and 1 nonintegrated linkage group from the second pedigree; their total length was 1372.2 cM. On average, the consensus map showed 1 marker every 3.0 cM. PCR-based codominant DNA markers such as cleaved amplified polymorphic sequences and microsatellite markers were distributed in all linkage groups and occupied about half of mapped loci. These markers are very useful for integration of different linkage maps, QTL mapping, and comparative mapping for evolutional study, especially for species with a large genome size such as conifers. 相似文献
5.
Typical linkage and quantitative trait locus (QTL) analyses in forest trees have been conducted in single pedigrees with sex-averaged
linkage maps. The results of a QTL analysis for wood quality and growth traits of coastal Douglas-fir using eight full-sib
families, each consisting of 40 progeny, replicated on four sites are presented. The resulting map of segregating genetic
markers consisted of 120 amplified fragment length polymorphism (AFLP) loci distributed across 19 linkage groups. The wood
quality traits represent the widest suite of traits yet examined for QTL analysis in a tree species in a single study. Wood
fiber traits showed the lowest number of QTLs (3) with relatively small effect (ca. 4%); wood density traits also showed just
three QTLs but with slightly larger effect; wood chemistry traits showed more QTLs (7), while ring density traits showed many
QTLs with large numbers of QTLs (78) and interesting patterns of temporal variation. Growth traits gave just five QTLs but
of major effect (10–16%). Trees, with their long generation times, provide a rich resource for studies of temporal variation
of QTL expression. 相似文献
6.
Identification and mode of action of quantitative trait loci affecting seedling height and leaf area in Eucalyptus nitens 总被引:6,自引:0,他引:6
M. Byrne J. C. Murrell J. V. Owen P. Kriedemann E. R. Williams G. F. Moran 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(5):674-681
Regions of the genome influencing height and leaf area in seedlings of a three-generation outbred pedigree of Eucalyptus nitens have been identified. Three QTLs affecting height and two QTLs affecting leaf area were located using single-factor analysis
of variance. The three QTLs affecting height each explained between 10.3 and 14.7% of the phenotypic variance, while the two
QTLs for leaf area each explained between 9.8 and 11.6% of the phenotypic variation. Analysis of fully informative marker
loci linked to the QTLs enabled the mode of action of the QTLs to be investigated. For three loci the QTL effect segregated
from only one parent, while for two loci the QTL showed multiple alleles and the effect segregated from both parents in the
pedigree. The two QTLs affecting leaf area were located in the same regions as two of the QTLs affecting height. Analysis
of these regions with fully informative markers showed that both QTLs were linked to the same markers, but one had a similar
size of effects and a similar mode of action for both height and leaf area, whilst the other showed a different mode of action
for the two traits. These regions may contain two closely linked genes or may involve a single gene with a pleiotrophic effect
on both height and leaf area. The QTL with the greatest effect showed multiple alleles and an intra-locus interaction that
reduced the size of the effect. Assessment for two of the QTLs in a second related family did not show an effect associated
with the marker loci; however, this was consistent with the mode of action of these QTLs and the pattern of inheritance in
the second family.
Received: 1 August 1996 / Accepted: 25 October 1996 相似文献
7.
Flavie Tortereau Hélène Gilbert Henri CM Heuven Jean-Pierre Bidanel Martien AM Groenen Juliette Riquet 《遗传、选种与进化》2010,42(1):42
Background
In pig, a number of experiments have been set up to identify QTL and a multitude of chromosomal regions harbouring genes influencing traits of interest have been identified. However, the mapping resolution remains limited in most cases and the detected QTL are rather inaccurately located. Mapping accuracy can be improved by increasing the number of phenotyped and genotyped individuals and/or the number of informative markers. An alternative approach to overcome the limited power of individual studies is to combine data from two or more independent designs.Methods
In the present study we report a combined analysis of two independent design (a French and a Dutch F2 experimental designs), with 2000 F2 individuals. The purpose was to further map QTL for growth and fatness on pig chromosomes 2, 4 and 6. Using QTL-map software, uni- and multiple-QTL detection analyses were applied separately on the two pedigrees and then on the combination of the two pedigrees.Results
Joint analyses of the combined pedigree provided (1) greater significance of shared QTL, (2) exclusion of false suggestive QTL and (3) greater mapping precision for shared QTL.Conclusions
Combining two Meishan x European breeds F2 pedigrees improved the mapping of QTL compared to analysing pedigrees separately. Our work was facilitated by the access to raw phenotypic data and DNA of animals from both pedigrees and the combination of the two designs with the addition of new markers allowed us to fine map QTL without phenotyping additional animals. 相似文献8.
Application of a new IBD-based QTL mapping method to common wheat breeding population: analysis of kernel hardness and dough strength 总被引:1,自引:0,他引:1
Crepieux S Lebreton C Flament P Charmet G 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,111(7):1409-1419
Mapping quantitative trait loci (QTL) in plants is usually conducted using a population derived from a cross between two inbred
lines. The power of such QTL detection and the estimation of the effects highly depend on the choice of the two parental lines.
Thus, the QTL found represent only a small part of the genetic architecture and can be of limited economical interest in marker-assisted
selection. On the other hand, applied breeding programmes evaluate large numbers of progeny derived from multiple-related
crosses for a wide range of agronomic traits. It is assumed that the development of statistical techniques to deal with pedigrees
in existing plant populations would increase the relevance and cost effectiveness of QTL mapping in a breeding context. In
this study, we applied a two-step IBD-based-variance component method to a real wheat breeding population, composed of 374
F6 lines derived from 80 different parents. Two bread wheat quality related traits were analysed by the method. Results obtained
show very close agreement with major genes and QTL already known for those two traits. With this new QTL mapping strategy,
inferences about QTL can be drawn across the breeding programme rather than being limited to the sample of progeny from a
single cross and thus the use of the detected QTL in assisting breeding would be facilitated. 相似文献
9.
In a previous study, several quantitative trait loci (QTLs) affecting vegetative propagation traits were detected in a hybrid
cross between Eucalyptus tereticornis and Eucalyptus globulus. The objective of this work was to confirm stable QTL linked markers (detected in different years) for propagation traits
in an independent set of the same segregating population and in two related crosses involving the original E. globulus parent. Phenotypic averages of groups of individuals carrying alternative allelic forms of the stable QTL linked markers
were statistically tested for significant differences. Adventitious rooting and petrification marker–trait associations, detected
previously in the E. tereticornis parent, were verified in an independent sample of the original progeny. In the E. globulus parent, the QTL linked marker was only verified in one related genetic background. Verification was possible only for high-effect
QTL linked markers. This study highlights the importance of sample size in QTL detection for low-heritability traits. 相似文献
10.
随着DNA分子标记技术的迅速发展,QTL定位已成为当前生物学研究领域的前沿。迄今已对许多种动、植物定位了许多重要性状的QTL。这些研究促进了遗传学的发展,并将作为育种的新策略应用。与作物相比,林木QTL定位有其特性。本文详细讨论了林木的生物学特性对QTL定位的影响、QTL定位的系谱设计和统计分析方法。 相似文献
11.
QTL analysis of white blood cell, platelet and red blood cell-related traits in an F2 intercross between Landrace and Korean native pigs 总被引:1,自引:0,他引:1
Cho IC Park HB Yoo CK Lee GJ Lim HT Lee JB Jung EJ Ko MS Lee JH Jeon JT 《Animal genetics》2011,42(6):621-626
Haematological traits play important roles in disease resistance and defence functions. The objective of this study was to locate quantitative trait loci (QTL) and the associated positional candidate genes influencing haematological traits in an F2 intercross between Landrace and Korean native pigs. Eight blood‐related traits (six erythrocyte traits, one leucocyte trait and one platelet trait) were measured in 816 F2 progeny. All experimental animals were genotyped with 173 informative microsatellite markers located throughout the pig genome. We report that nine chromosomes harboured QTL for the baseline blood parameters: genomic regions on SSC 1, 4, 5, 6, 8, 9, 11, 13 and 17. Eight of twenty identified QTL reached genome‐wide significance. In addition, we evaluated the KIT locus, an obvious candidate gene locus affecting variation in blood‐related traits. Using dense single nucleotide polymorphism marker data on SSC 8 and the marker‐assisted association test, the strong association of the KIT locus with blood phenotypes was confirmed. In conclusion, our study identified both previously reported and novel QTL affecting baseline haematological parameters in pigs. Additionally, the positional candidate genes identified here could play an important role in elucidating the genetic architecture of haematological phenotype variation in swine and in humans. 相似文献
12.
Blair MW Iriarte G Beebe S 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2006,112(6):1149-1163
Advanced backcross QTL analysis was used to identify quantitative trait loci (QTL) for agronomic performance in a population
of BC2F3:5 introgression lines created from the cross of a Colombian large red-seeded commercial cultivar, ICA Cerinza, and a wild common
bean accession, G24404. A total of 157 lines were evaluated for phenological traits, plant architecture, seed weight, yield
and yield components in replicated trials in three environments in Colombia and genotyped with microsatellite, SCAR, and phaseolin
markers that were used to create a genetic map that covered all 11 linkage groups of the common bean genome with markers spaced
at an average distance of every 10.4 cM. Segregation distortion was most significant in regions orthologous for a seed coat
color locus (R-C) on linkage group b08 and two domestication syndrome genes, one on linkage group b01 at the determinacy (fin) locus and the other on linkage group b02 at the seed-shattering (st) locus. Composite interval mapping analysis identified a total of 41 significant QTL for the eight traits measured of which
five for seed weight, two for days to flowering, and one for yield were consistent across two or more environments. QTL were
located on every linkage group with b06 showing the greatest number of independent loci. A total of 13 QTL for plant height,
yield and yield components along with a single QTL for seed size showed positive alleles from the wild parent while the remaining
QTL showed positive alleles from the cultivated parent. Some QTL co-localized with regions that had previously been described
to be important for these traits. Compensation was observed between greater pod and seed production and smaller seed size
and may have resulted from QTL for these traits being linked or pleiotropic. Although wild beans have been used before to
transfer biotic stress resistance traits, this study is the first to attempt to simultaneously obtain a higher yield potential
from wild beans and to analyze this trait with single-copy markers. The wild accession was notable for being from a unique
center of diversity and for contributing positive alleles for yield and other traits to the introgression lines showing the
potential that advanced backcrossing has in common bean improvement. 相似文献
13.
Pedunculate oak and sessile oak are two sympatric interfertile species that exhibit leaf morphological differences. We aimed to detect quantitative trait loci (QTLs) of these traits in order to locate genomic regions involved in species differentiation. A total of 15 leaf morphological traits were assessed in a mixed forest stand composed of Quercus petraea and Q. robur and in a full-sib pedigree of Q. robur. The progeny of the full-sib family were vegetatively propagated in two successive experiments comprising 174 and 216 sibs, and assessments were made on two leaves collected on each of the 1080 and 1530 cuttings corresponding to the two experiments. Traits that exhibited strong species differences in the mixed stand tended also to have higher repeatability values in the mapping population, thus indicating higher genetic control. A genetic map was constructed for QTL detection. Composite interval mapping with the one QTL model was used for QTL detection. From one to three QTLs were detected for 13 traits. In-depth analysis of the QTLs, controlling the five morphological traits that exhibited the highest interspecific differences in the mixed stand, indicated that they were distributed on six linkage groups, with two clusters comprising QTLs of at least two discriminant traits. These results were reinforced when error 1 for QTL detection was set at 5% at the chromosome level, as up to nine clusters could be identified. In conclusion, traits involved in interspecific differentiation of oaks are under polygenic control and widespread in clusters across the genome. 相似文献
14.
Z. Kaya M. M. Sewell D. B. Neale 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(3-4):586-592
Quantitative trait loci (QTLs) for annual height- and diameter-increment growth were estimated in each of two three-generation
loblolly pine pedigrees. Annual height-increment was measured in three consecutive years in the BASE pedigree and in four consecutive years in the QTL pedigree. Annual diameter-increment was measured only in the QTL pedigree for two consecutive years. An interval mapping-approach was used to estimate the number of QTLs, the magnitude of
QTL effects, and their position on genetic linkage maps. Thirteen different height-increment and eight different diameter-increment
QTLs were detected, suggesting that the these traits are, at least in part, controlled by a few genes of large effect. Little
evidence was found for the expression of individual QTLs in multiple years or in multiple genetic backgrounds. These results
were discussed in terms of the power of the experiment and their consequences for marker-assisted breeding.
Received: 12 July 1998/Accepted: 5 August 1998 相似文献
15.
Quantitative trait loci (QTL) detection was carried out for adventitious rooting and associated propagation traits in a second-generation
outbred Corymbia torelliana × Corymbia citriodora subspecies variegata hybrid family (n = 186). The parental species of this cross are divergent in their capacity to develop roots adventitiously on stem cuttings
and their propensity to form lignotubers. For the ten traits studied, there was one or two QTL detected, with some QTL explaining
large amounts of phenotypic variation (e.g. 66% for one QTL for percentage rooting), suggesting that major effects influence
rooting in this cross. Collocation of QTL for many strongly genetically correlated rooting traits to a single region on linkage
group 12 suggested pleiotropy. A three locus model was most parsimonious for linkage group 12, however, as differences in
QTL position and lower genetic correlations suggested separate loci for each of the traits of shoot production and root initiation.
Species differences were thought to be the major source of phenotypic variation for some rooting rate and root quality traits
because of the major QTL effects and up to 59-fold larger homospecific deviations (attributed to species differences) relative
to heterospecific deviations (attributed to standing variation within species) evident at some QTL for these traits. A large
homospecific/heterospecific ratio at major QTL suggested that the gene action evident in one cross may be indicative of gene
action more broadly in hybrids between these species for some traits. 相似文献
16.
QTL mapping of yield and fiber traits based on a four-way cross population in <Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L. 总被引:2,自引:0,他引:2
Qin H Guo W Zhang YM Zhang T 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2008,117(6):883-894
Four-way cross (4WC) involving four different inbred lines frequently appears in the cotton breeding programs. However, linkage
analysis and quantitative trait loci (QTL) mapping with molecular markers in cotton has largely been applied to populations
derived from a cross between two inbred lines, and few results of QTL dissection were conducted in a 4WC population. In this
study, an attempt was made to construct a linkage map and identify QTL for yield and fiber quality traits in 4WC derived from
four different inbred lines in Gossypium hirsutum L. A linkage map was constructed with 285 SSR loci and one morphological locus, covering 2113.3 cM, approximately 42% of
the total recombination length of the cotton genome. A total of 31 QTL with 5.1–25.8% of the total phenotypic variance explained
were detected. Twenty-four common QTL across environments showed high stability, and six QTL were environment-specific. Several
genomic segments affecting multiple traits were identified. The advantage of QTL mapping using a 4WC were discussed. This
study presents the first example of QTL mapping using a 4WC population in upland cotton. The results presented here will enhance
the understanding of the genetic basis of yield and fiber quality traits and enable further marker-assisted selection in cultivar
populations in upland cotton. 相似文献
17.
H. W. Raadsma E. Jonas M. R. Fleet K. Fullard J. Gongora C. R. Cavanagh I. Tammen P. C. Thomson 《Animal genetics》2013,44(5):547-559
The pursuits of white features and white fleeces free of pigmented fibre have been important selection objectives for many sheep breeds. The cause and inheritance of non‐white colour patterns in sheep has been studied since the early 19th century. Discovery of genetic causes, especially those which predispose pigmentation in white sheep, may lead to more accurate selection tools for improved apparel wool. This article describes an extended QTL study for 13 skin and fibre pigmentation traits in sheep. A total of 19 highly significant, 10 significant and seven suggestive QTL were identified in a QTL mapping experiment using an Awassi × Merino × Merino backcross sheep population. All QTL on chromosome 2 exceeded a LOD score of greater than 4 (range 4.4–30.1), giving very strong support for a major gene for pigmentation on this chromosome. Evidence of epistatic interactions was found for QTL for four traits on chromosomes 2 and 19. The ovine TYRP1 gene on OAR 2 was sequenced as a strong positional candidate gene. A highly significant association (P < 0.01) of grandparental haplotypes across nine segregating SNP/microsatellite markers including one non‐synonymous SNP with pigmentation traits could be shown. Up to 47% of the observed variation in pigmentation was accounted for by models using TYRP1 haplotypes and 83% for models with interactions between two QTL probabilities, offering scope for marker‐assisted selection for these traits. 相似文献
18.
A genome scan reveals QTL for growth, fatness, leanness and meat quality in a Duroc-Pietrain resource population 总被引:3,自引:0,他引:3
Liu G Jennen DG Tholen E Juengst H Kleinwächter T Hölker M Tesfaye D Un G Schreinemachers HJ Murani E Ponsuksili S Kim JJ Schellander K Wimmers K 《Animal genetics》2007,38(3):241-252
We performed a genome-wide QTL scan for production traits in a line cross between Duroc and Pietrain breeds of pigs, which included 585 F(2) progeny produced from 31 full-sib families genotyped with 106 informative microsatellites. A linkage map covering all 18 autosomes and spanning 1987 Kosambi cM was constructed. Thirty-five phenotypic traits including body weight, growth, carcass composition and meat quality traits were analysed using least square regression interval mapping. Twenty-four QTL exceeded the genome-wide significance threshold, while 47 QTL reached the suggestive threshold. These QTL were located at 28 genomic regions on 16 autosomal chromosomes and QTL in 11 regions were significant at the genome-wide level. A QTL affecting pH value in loin was detected on SSC1 between marker-interval S0312-S0113 with strong statistical support (P < 3.0 x 10(-14)); this QTL was also associated with meat colour and conductivity. QTL for carcass composition and average daily gain was also found on SSC1, suggesting multiple QTL. Seventeen genomic segments had only a single QTL that reached at least suggestive significance. Forty QTL exhibited additive inheritance whereas 31 QTL showed (over-) dominance effects. Two QTL for trait backfat thickness were detected on SSC2; a significant paternal effect was found for a QTL in the IGF2 region while another QTL in the middle of SSC2 showed Mendelian expression. 相似文献
19.
Ross D. Houston Chris S. Haley Alan L. Archibald Kellie A. Rance 《Mammalian genome》2005,16(6):464-470
Our understanding of the molecular genetic basis of several key performance traits in pigs has been significantly advanced through the quantitative trait loci (QTL) mapping approach. However, in contrast to growth and fatness traits, the genetic basis of feed intake traits has rarely been investigated through QTL mapping. Since feed intake is an important component of efficient pig production, the identification of QTL affecting feed intake may lead to the identification of genetic markers that can be used in selection programs. In this study a QTL analysis for feed intake, feeding behavior, and growth traits was performed in an F2 population derived from a cross between Chinese Meishan and European Large White pigs. A QTL with a significant effect on daily feed intake (DFI) was identified on Sus scrofa Chromosome 2 (SSC2). A number of suggestive QTL with effects on daily gain, feed conversion, and feeding behavior traits were also located. The significant QTL lies close to a previously identified mutation in the insulin-like growth factor 2 gene (IGF2) that affects carcass composition traits, although the IGF2 mutation is not segregating in the populations analyzed in the current study. Therefore, a distinct causal variant may exist on the P arm of SSC2 with an effect on feed intake. 相似文献
20.
Identification of Quantitative Trait Loci Influencing Wood Specific Gravity in an Outbred Pedigree of Loblolly Pine 总被引:16,自引:1,他引:15
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A. Groover M. Devey T. Fiddler J. Lee R. Megraw T. Mitchel-Olds B. Sherman S. Vujcic C. Williams D. Neale 《Genetics》1994,138(4):1293-1300
We report the identification of quantitative trait loci (QTL) influencing wood specific gravity (WSG) in an outbred pedigree of loblolly pine (Pinus taeda L.). QTL mapping in an outcrossing species is complicated by the presence of multiple alleles (>2) at QTL and marker loci. Multiple alleles at QTL allow the examination of interaction among alleles at QTL (deviation from additive gene action). Restriction fragment length polymorphism (RFLP) marker genotypes and wood specific gravity phenotypes were determined for 177 progeny. Two RFLP linkage maps were constructed, representing maternal and paternal parent gamete segregations as inferred from diploid progeny RFLP genotypes. RFLP loci segregating for multiple alleles were vital for aligning the two maps. Each RFLP locus was assayed for cosegregation with WSG QTL using analysis of variance (ANOVA). Five regions of the genome contained one or more RFLP loci showing differences in mean WSG at or below the P = 0.05 level for progeny as grouped by RFLP genotype. One region contained a marker locus (S6a) whose QTL-associated effects were highly significant (P > 0.0002). Marker S6a segregated for multiple alleles, a prerequisite for determining the number of alleles segregating at the linked QTL and analyzing the interactions among QTL alleles. The QTL associated with marker S6a appeared to be segregating for multiple alleles which interacted with each other and with environments. No evidence for digenic epistasis was found among the five QTL. 相似文献