marker locus

mark·er lo·cus

a locus on a chromosome or in a stretch of DNA that can be identified (for example, a restriction fragment length polymorphism) and can serve in linkage analysis and in the isolation of a disease gene.
See also: linkage marker.
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References in periodicals archive ?
In the study of population genetic structure, the PIC is one of the key indicators to measure the genetic variation and polymorphism of a marker locus in a population.
On the other hand, the spontaneous mutations in the germline of the putative father at any genetic marker locus used in the analysis can lead to an erroneous exclusion because such mutation results in differences between the parent and offspring.
There were 2 alleles in each marker locus. The original marker allele frequencies (donor/receptor) was 0.95/0.05, 0.90/0.10, 0.80/0.20, 0.70/0.30, 0.60/ 0.40 and 0.50/0.50.
Allele-counting schemes for discordant half sib pairs Case Half sib genotypes Alleles counted Scheme 1 Scheme 2 1 11 11 1,1 1,1 -- -- 2 11 12 1,1 1,2 1 2 3 11 22 1,1 2,2 1,1 2,2 * 1 and 2 represent distinct alleles at the marker locus. Adapted from Boehnke and Langefeld (1998).
The trait associations with these two alleles of this single SSR marker locus are those that we would expect of a QTL having substantial pleiotropic effects on these related traits.
We found a Lod score of 2.31 at [theta]=0 at marker locus D2S319.
Patients with a homozygous mutation may not have the same allele size at the selected marker locus if the 2 mutant alleles do not have a common origin (3).
Now consider the phenotypic values associated with a marker locus. Although the molecular marker is considered functionally neutral, it can affect the expectation of phenotypic value by changing the probabilities of the alleles at L and the expectation of the polygenic effect.
His analysis has shown that associative overdominance is most strongly expressed in the simultaneous presence of both inbreeding and linkage disequilibrium between the marker locus and tightly linked deleterious genes.
Chi-square tests were performed for each marker locus to determine if the segregation ratio conformed to 1:1.
The effective selection ([s.sub.eL], [s.sub.eR]) acting on each marker locus can be estimated from [s.sup.*] and the decay rates ([[Theta].sub.L], [[Theta].sub.R]; [ILLUSTRATION FOR FIGURE 2 OMITTED]) on either side of the zone.
Linkage groups (LG), likelihood odds (LOD) scores and positions for quantitative trait locus (QTL) peaks on the genetic map (cM), 1.0-LOD support intervals, genetic marker intervals spanning QTL peaks, closest genetic marker locus to the QTL peak, phenotypic coefficients of determination ([R.sup.2.sub.P]), and additive genetic effects (a) for seed oil concentration (soc, g [kg.sup.-1]), 100- seed weight (swt; g), seed length (sl; mm), width (sw; mm), and depth (sd; mm), 10-kernel weight (kwt; g), 10-pericarp weight (pwt; g), and kernel-to-pericarp weight ratio (kpr) QTL segregating in the RHA280 x RHA801 recombinant inbred line mapping population, where a = ([y.sub.RHA801] - [y.sub.RHA280]) is the [y.sub.RHA280] homozveote mean, and [y.sub.RHA801] is the RHA801 homozyeote mean.