The effects of three muscling Quantitative Trait Loci on growth patterns of crossbred lambs

2009 ◽  
Vol 2009 ◽  
pp. 40-40
Author(s):  
N R Lambe ◽  
J M Macfarlane ◽  
A Masri ◽  
O Matika ◽  
W Haresign ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Growth Rates ◽  
Quantitative Trait ◽  
Growth Patterns ◽  
Chromosome 2 ◽  
Chromosome 18 ◽  
Fast Growing ◽  
Trait Loci

Texel Muscling QTL (TM-QTL) and LoinMaxTM (LM-QTL) are located on chromosome 18 in Texel and Poll Dorset sheep, respectively, and have been shown to positively affect muscling of the loin in crossbred lambs carrying one copy of the QTL (Macfarlane et al., 2008, Masri et al., 2009). MyoMaxTM (MM-QTL), found on chromosome 2 of Texel sheep, increases muscling and decreases fatness in lambs of different genetic backgrounds (Campbell and McLaren, 2007). No differences in live weights, carcass weights or growth rates have been associated with these QTL to date. However, there is further need to investigate the effects of the three QTL on growth patterns in commercial crossbred populations, where fast-growing slaughter lambs of good carcass weights and quality are a prerequisite.

scholarly journals Quantitative Trait Loci Associated with Rotylenchulus reniformis Host Suitability in Soybean

2020 ◽  
Vol 110 (9) ◽  
pp. 1511-1521
Author(s):  
Juliet Wilkes ◽  
Christopher Saski ◽  
Mariola Klepadlo ◽  
Benjamin Fallen ◽  
Paula Agudelo
Keyword(s):  
Quantitative Trait Loci ◽  
Qtl Analysis ◽  
Quantitative Trait ◽  
The United States ◽  
Host Suitability ◽  
Reniform Nematode ◽  
Rotylenchulus Reniformis ◽  
Chromosome 18 ◽  
Nematode Reproduction ◽  
Trait Loci

Reniform nematode (Rotylenchulus reniformis) is a yield-limiting pathogen of soybean (Glycine max) in the southeastern region of the United States. A population of 250 recombinant inbred lines (RIL) (F2:8) developed from a cross between reniform nematode resistant soybean cultivar Forrest and susceptible cultivar Williams 82 was utilized to identify regions associated with host suitability. A genetic linkage map was constructed using single-nucleotide polymorphism markers generated by genotyping-by-sequencing. The phenotype was measured in the RIL population and resistance was characterized using normalized and transformed nematode reproduction indices in an optimal univariate cluster analysis. Quantitative trait loci (QTL) analysis using normalized phenotype scores identified two QTLs on each arm of chromosome 18 (rrn-1 and rrn-2). The same QTL analysis performed with log10(x) transformed phenotype data also identified two QTLs: one on chromosome 18 overlapping the same region in the other analysis (rrn-1), and one on chromosome 11 (rrn-3). While rrn-1 and rrn-3 have been reported associated with reduced reproduction of reniform nematode, this is the first report of the rrn-2 region associated with host suitability to reniform nematode. The resistant parent allele at rrn-2 showed an inverse relationship with the resistance phenotype, correlating with an increase in nematode reproduction or host suitability. Several candidate genes within these regions corresponded with host plant defense systems. Interestingly, a characteristic pathogen resistance gene with a leucine-rich repeat was discovered within rrn-2. These genetic markers can be used by soybean breeders in marker-assisted selection to develop lines with resistance to reniform nematode.

Identification of stably expressed quantitative trait loci for cooked rice elongation in non-Basmati varieties

Genome ◽  
2008 ◽  
Vol 51 (2) ◽  
pp. 104-112 ◽  
Author(s):  
L. L. Liu ◽  
X. Y. Yan ◽  
L. Jiang ◽  
W. W. Zhang ◽  
M. Q. Wang ◽  
...  
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Recombinant Inbred Lines ◽  
Basmati Rice ◽  
Eating Quality ◽  
Chromosome 2 ◽  
Elongation Ratio ◽  
Substitution Lines ◽  
Chromosome Segment Substitution Lines ◽  
Trait Loci

The elongation of the cooked grain determines the cooking and eating quality of Basmati rice. The identification of stable quantitative trait loci (QTLs), especially those from non-Basmati types, will extend the genetic basis of the Basmati type and facilitate the breeding of high-quality varieties. A set of recombinant inbred lines derived from an indica × japonica hybrid was used to identify QTLs controlling the elongation ratio (ER), elongation index (EI), and water absorption (WA) of the cooked grain. Three ER QTLs on chromosomes 2, 4, and 12, two EI QTLs on chromosomes 2 and 5, and two WA QTLs on chromosomes 2 and 6 were detected. Four of these QTLs were validated using a set of established chromosome segment substitution lines. The genetic effect of qER-2 was explored in an analysis of segregating generations, using 8 newly developed simple sequence repeat markers. Two tightly linked loci (qER-2a and qER-2b) were identified on chromosome 2.

RFLP mapping of five major genes and eight quantitative trait loci controlling flowering time in a winter × spring barley (Hordeum vulgare L.) cross

Genome ◽  
1995 ◽  
Vol 38 (3) ◽  
pp. 575-585 ◽  
Author(s):  
D. A. Laurie ◽  
N. Pratchett ◽  
J. W. Snape ◽  
J. H. Bezant
Keyword(s):  
Quantitative Trait Loci ◽  
Hordeum Vulgare ◽  
Flowering Time ◽  
Quantitative Trait ◽  
Field Experiments ◽  
Chromosome 2 ◽  
Vernalization Response ◽  
Major Genes ◽  
Trait Loci ◽  
Glasshouse Experiment

A genetic map of 92 RFLP loci and two storage protein loci was made using 94 doubled-haploid lines from a cross between the winter barley variety Igri and the spring variety Triumph. The markers were combined with data from two field experiments (one spring sown and one autumn (fall) sown) and a glasshouse experiment to locate a total of 13 genes (five major genes and eight quantitative trait loci (QTL)) controlling flowering time. Two photoperiod response genes were found; Ppd-H1 on chromosome 2(2H)S regulated flowering time under long days, while Ppd-H2 on chromosome 5(1H)L was detected only under short days. In the field experiments Ppd-H1 strongly affected flowering time from spring and autumn sowings, while Ppd-H2 was detected only in the autumn sowing. The glasshouse experiment also located two vernalization response genes, probably Sh and Sh2, on chromosomes 4(4H)L and 7(5H)L, respectively. The vernalization response genes had little effect on flowering time in the field. Variation in flowering time was also affected by nine additional genes, whose effects were not specifically dependent on photoperiod or vernalization. One was the denso dwarfing gene on chromosome 3(3H)L. The remaining eight were QTLs of smaller effect. One was located on chromosome 2(2H), one on 3(3H), one on 4(4H), one on 7(5H), two on 6(6H), and two on 1(7H). Model fitting showed that the 13 putative genes, and their interactions, could account for all the observed genetical variation from both spring and autumn sowings, giving a complete model for the control of flowering time in this cross.Key words: barley, Hordeum vulgare, flowering time, photoperiod, vernalization, mapping.

scholarly journals Mapping Quantitative Trait Loci Underlying Circadian Light Sensitivity in Drosophila

2017 ◽  
Vol 32 (5) ◽  
pp. 394-405 ◽  
Author(s):  
Adeolu B. Adewoye ◽  
Sergey V. Nuzhdin ◽  
Eran Tauber
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Recombinant Inbred ◽  
Recombinant Inbred Lines ◽  
Transcriptome Profiling ◽  
Light Sensitivity ◽  
Significant Advance ◽  
Chromosome 2 ◽  
Light Entrainment ◽  
Trait Loci

Despite the significant advance in our understanding of the molecular basis of light entrainment of the circadian clock in Drosophila, the underlying genetic architecture is still largely unknown. The aim of this study was to identify loci associated with variation in circadian photosensitivity, which are important for the evolution of this trait. We have used complementary approaches that combined quantitative trait loci (QTL) mapping, complementation testing, and transcriptome profiling to dissect this variation. We identified a major QTL on chromosome 2, which was subsequently fine mapped using deficiency complementation mapping into 2 smaller regions spanning 139 genes, some of which are known to be involved in functions that have been previously implicated in light entrainment. Two genes implicated with the clock and located within that interval, timeless and cycle, failed to complement the QTL, indicating that alleles of these genes contribute to the variation in light response. Specifically, we find that the timeless s/ ls polymorphism that has been previously shown to constitute a latitudinal cline in Europe is also segregating in our recombinant inbred lines and is contributing to the phenotypic variation in light sensitivity. We also profiled gene expression in 2 recombinant inbred strains that differ significantly in their photosensitivity and identified a total of 368 transcripts that showed differential expression (false discovery rate < 0.1). Of 131 transcripts that showed a significant recombinant inbred line by treatment interaction (i.e., putative expression QTL), 4 are located within QTL2.

Quantitative trait loci for heading date and straw characters in barley

Genome ◽  
1995 ◽  
Vol 38 (6) ◽  
pp. 1098-1104 ◽  
Author(s):  
B. Kjær ◽  
J. Jensen ◽  
H. Giese
Keyword(s):  
Quantitative Trait Loci ◽  
Hordeum Vulgare ◽  
Doubled Haploid ◽  
Quantitative Trait ◽  
Rapd Markers ◽  
Spring Barley ◽  
Heading Date ◽  
Chromosome 6 ◽  
Chromosome 2 ◽  
Trait Loci

Quantitative trait loci (QTLs) for heading date and straw characters were examined in 79 chromosome-doubled haploid lines derived from the F1 generation of a cross between a six-rowed winter barley and a two-rowed spring barley. A genetic map covering 1100 cM containing 85 markers, including isozyme, morphological, RFLP, and RAPD markers, was constructed. All traits examined had two QTLs with large effects on chromosome 2. In addition, a QTL for length of the top internode was found on chromosome 6. The QTL in the chromosome segment around locus v (two row/six row) on chromosome 2 may be caused by pleiotropic effects of this locus. The same QTLs for heading date and straw length were found in both 1989 and 1991. The results indicate that two QTLs on chromosome 2 affect a group of correlated traits.Key words: Hordeum vulgare, earliness, RFLP, two rowed, six rowed, linkage map.

scholarly journals Mapping quantitative trait loci underlying circadian light sensitivity in Drosophila

2017 ◽  
Author(s):  
Adeolu B. Adewoye ◽  
Sergey V. Nuzhdin ◽  
Eran Tauber
Keyword(s):  
Quantitative Trait Loci ◽  
Quantitative Trait ◽  
Recombinant Inbred ◽  
Recombinant Inbred Lines ◽  
Transcriptome Profiling ◽  
Light Sensitivity ◽  
Significant Advance ◽  
Chromosome 2 ◽  
Light Entrainment ◽  
Trait Loci

AbstractDespite the significant advance in our understanding of the molecular basis of light entrainment of the circadian clock in Drosophila, the underlying genetic architecture is still largely unknown. The aim of this study was to identify loci associated with variation in circadian photosensitivity, which are important for the evolution of this trait. We have used complementary approaches that combined quantitative trait loci (QTL) mapping, complementation testing and transcriptome profiling to dissect this variation.We identified a major QTL on chromosome 2, which was subsequently fine-mapped using deficiency complementation mapping into two smaller regions spanning 139 genes, some of which are known to be involved in functions which have been previously implicated in light entrainment. Two genes implicated with the clock and located within that interval, timeless and cycle, failed to complement the QTL, indicating that alleles of these genes contribute to the variation in light response. Specifically, we find that the timeless s/ls polymorphism that has been previously shown to constitute a latitudinal cline in Europe, is also segregating in our recombinant inbred lines, and is contributing to the phenotypic variation in light sensitivity.We have also profiled gene expression in two recombinant inbred strains that differ significantly in their photosensitivity, and identified a total of 368 transcripts that showed differential expression (FDR < 0.1). Out of 131 transcripts that showed a significant RIL by treatment interaction (i.e. putative expression QTL), four are located within QTL2

Deficiency Mapping of Quantitative Trait Loci Affecting Longevity inDrosophila melanogaster

Genetics ◽  
2000 ◽  
Vol 156 (3) ◽  
pp. 1129-1146 ◽  
Author(s):  
Elena G Pasyukova ◽  
Cristina Vieira ◽  
Trudy F C Mackay
Keyword(s):  
Quantitative Trait Loci ◽  
Life Span ◽  
Quantitative Trait ◽  
Recombinant Inbred Lines ◽  
Inbred Lines ◽  
Adult Longevity ◽  
Chromosome 2 ◽  
Recombination Mapping ◽  
Trait Loci ◽  
E Region

AbstractIn a previous study, sex-specific quantitative trait loci (QTL) affecting adult longevity were mapped by linkage to polymorphic roo transposable element markers, in a population of recombinant inbred lines derived from the Oregon and 2b strains of Drosophila melanogaster. Two life span QTL were each located on chromosomes 2 and 3, within sections 33E–46C and 65D–85F on the cytological map, respectively. We used quantitative deficiency complementation mapping to further resolve the locations of life span QTL within these regions. The Oregon and 2b strains were each crossed to 47 deficiencies spanning cytological regions 32F–44E and 64C–76B, and quantitative failure of the QTL alleles to complement the deficiencies was assessed. We initially detected a minimum of five and four QTL in the chromosome 2 and 3 regions, respectively, illustrating that multiple linked factors contribute to each QTL detected by recombination mapping. The QTL locations inferred from deficiency mapping did not generally correspond to those of candidate genes affecting oxidative and thermal stress or glucose metabolism. The chromosome 2 QTL in the 35B–E region was further resolved to a minimum of three tightly linked QTL, containing six genetically defined loci, 24 genes, and predicted genes that are positional candidates corresponding to life span QTL. This region was also associated with quantitative variation in life span in a sample of 10 genotypes collected from nature. Quantitative deficiency complementation is an efficient method for fine-scale QTL mapping in Drosophila and can be further improved by controlling the background genotype of the strains to be tested.

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