We present a two-phase strategy for optimizing a multidimensional, nonconvex function arising during genetic mapping of quantitative traits. Such traits are believed to be affected by multiple so called quantitative trait loci (QTL), and searching for d QTL results in a d-dimensional optimization problem with a large number of local optima. We combine the global algorithm DIRECT with a number o...

A genetic map containing 103 microsatellite loci and 200 F2 plants derived from the cross R15 × Ye478 were used for mapping of quantitative trait loci (QTL) in maize (Zea mays L.). QTLs were characterized in a population of 200 F2:4 lines, derived from selfing the F2 plants, and were evaluated with two replications in two environments. QTL mapping analysis of plant height was performed by using...

in the current study, a set of 96 recombinant inbred lines (ril) at f8, derived from a cross between two varieties, anbarbu (sensitive to drought stress) and sepidroud (tolerant to drought stress) were used. the experiment was performed at gonbad kavous located in the golestan province of iran in 2010–2011 using two augmented designs at normal and stress conditions, separately. the ril populati...

two breeds of chickens were used to develop reference family and detect qtls affecting egg quality traits: cocks of a native polish breed green-legged partidgenous (glp) and hens of rhode island red (rir). during the first 100 days of the laying period, the glp hens lay about 40 eggs weighting on average 50 g, whilst the rir flock laid 83 eggs with a mean weight of 60 g. qtl analysis of egg qua...

many qtls related to agronomic triats have been registered in soybean (glycine max) by different research groups during the last decade. due to the interaction effects of qtls, environmental and genetic backgrounds on the emergence of qtls and also to confirm the previous results as well as to identify new qtls, further studies are still required. in order to map qtl which control some agronomi...

The selective genotyping approach, where only individuals from the high and low extremes of the trait distribution are selected for genotyping and the remaining individuals are not genotyped, has been known as a cost-saving strategy to reduce genotyping work and can still maintain nearly equivalent efficiency to complete genotyping in QTL mapping. We propose a novel and simple statistical metho...

Identifying the genetic basis of complex traits is an important problem with the potential to impact a broad range of biological endeavors. A number of effective statistical methods are available for quantitative trait loci (QTL) mapping that allow for the efficient identification of multiple, potentially interacting, loci under a variety of experimental conditions. Although proven useful in hu...

Complex traits such as crop performance and human diseases are controlled by multiple genetic loci, many of which have small effects and often go undetected by traditional quantitative trait locus (QTL) mapping. Recently, bulked segregant analysis with large F2 pools and genome-level markers (named extreme-QTL or X-QTL mapping) has been used to identify many QTL. To estimate parameters impactin...

Carlborg, Ö. 2002. New Methods for Mapping Quantitative Trait Loci. Doctoral dissertation. ISSN 1401-6257, ISBN 91-576-6362-9 This thesis presents and discusses the use of various genetic models, high performance computing, global optimization algorithms and statistical methods for mapping Quantitative Trait Loci (QTL). The aim of the work has been to develop statistically powerful and computat...

The differences between maximum-likelihood (ML) and regression (REG) interval mapping in the analysis of quantitative trait loci (QTL) are investigated analytically and numerically by simulation. The analytical investigation is based on the comparison of the solution sets of the ML and REG methods in the estimation of QTL parameters. Their differences are found to relate to the similarity betwe...