Qtl mapping thesis

Second, we must discard individuals whose genotypes are missing at the marker. All the lines were planted in the field using a randomized block.

Due to the involved nature of genetic investigations needed to determine such inheritance patterns, this is not usually the first avenue of investigation one would choose to determine etiology. If multifactorial inheritance is indeed the case, then the chance of the patient contracting the disease is reduced only if cousins and more distant relatives have the disease.

This often takes several years. Introduction Cotton Gossypium L. The QTL mapping of fiber quality traits could provide a solid foundation for future studies concerning marker-assisted selection breeding and map-based cloning. Usually, multifactorial traits outside of illness result in what we see as continuous characteristics in organisms, especially human organisms such as: The map file contains map name, marker name, and distance between adjacent makers, etc.

As the most important cotton cultivar, much research attention has been paid to the improvement of the fiber quality and yield of upland cotton. Because of the low genetic polymorphism between the intraspecific hybridization of upland cotton, several high-density interspecific linkage maps between G.

The objectives of this study were to construct an intraspecific upland cotton map using SSRs, InDels and SNPs based on this RIL population, which was used to detect QTL associated with fiber quality and yield traits under multiple environmental conditions.

A chi-square test was performed to determine whether the genotypic frequencies at each locus deviated from the expected 1: The choice of marker covariates has not been solved, however. Instead the contributions of each involved locus are thought to be additive.

Fortunately, the development of genetic linkage maps facilitate the dissection of quantitative trait loci QTL that control fiber qualities and yield components, which make it possible to pyramid elite genes of fiber quality and yield traits.

Family based QTL mapping has been the only way for mapping of genes where experimental crosses are difficult to make. In recent decades, improvements in cotton fiber quality and yield have been stagnant and unable to meet the demands of the modern textile industry.

Family-based linkage and association has been successfully implemented Rosyara et al. The fiber quality data in E7 and yield components in E1 were lost, and combined analysis E9 was conducted after determining the mean values in seven environments.

A total of 26 QTL hotspot regions were observed on 13 chromosomes and 2 larger linkage groups, and some QTL clusters related to fiber qualities or yield components were also observed.

The RIL population performed transgressive segregation on all traits. Results Trait performance and correlation analysis in the RIL population The traits of fiber qualities and yield components are summarized in S1 Table.

In interval mapping, each locus is considered one at a time and the logarithm of the odds ratio LOD score is calculated for the model that the given locus is a true QTL.

Quantitative trait locus

The conditional values for the first trait are estimated for the no variation situation in the secondary trait and analysis can be conducted on the conditional as well as unconditional data. The more genes involved in the cross, the more the distribution of the genotypes will resemble a normal, or Gaussian distribution.

Interval mapping is currently the most popular approach for QTL mapping in experimental crosses. Not surprisingly, the appropriate markers are those closest to the true QTLs, and so if one could find these, the QTL mapping problem would be complete anyway. Second, recording data at different growth stages allows one to estimate the conditional genetic effects using the method proposed by Zhu The broad-sense heritabilities of measured traits were calculated according to the method of Knapp et al.

QTL Mapping

Jimian5 is a cultivar with high yield as a male parent. These fields are only used for research purposes, and the field studies did not involve endangered or protected species. And the broad-sense heritabilities of the fiber quality and yield component traits were showed in Table 1.

If the genome is not available, it may be an option to sequence the identified region and determine the putative functions of genes by their similarity to genes with known function, usually in other genomes.

Writers have distinguished this kind of inheritance as polygenic, or quantitative inheritance. Data analysis, genetic map construction and QTL analysis The difference between the two parents for each trait was detected using a t-test.

QTL Mapping for Fiber and Yield Traits in Upland Cotton under Multiple Environments

However, due to some advantages, now plant geneticists are attempting to incorporate some of the methods pioneered in human genetics. The Qtl mapping thesis markers were not genotyped in this RIL population because these polymorphisms are difficult to crosstalk with those identified in previous studies.

The statistical significance of the LOD threshold value was determined using a permutation procedure 1, times for all traits. In this method, in a backcross, one may calculate a t-statistic to compare the averages of the two marker genotype groups.

When more than one gene is involved, with or without the presence of environmental triggers, we say that the disease is the result of multifactorial inheritance. The coefficients of genetic correlation between measured traits were computed according to the method of Kwon and Torrie [ 30 ].

Third, conditional mapping can also be conducted using two different correlated traits to see the effect of one trait on the detection of QTL for the other related trait for example, grain protein content and thousand grain weight or grain yield in wheat.

However, QTLs located elsewhere on the genome can have an interfering effect.QTL Mapping QTL mapping is a method utilized to define the general chromosomal position of genes or genetic variants that influence the magnitude of a measurable trait.

From: Encyclopedia of Basic Epilepsy Research, GENETIC MAPPING OF QTL FOR FUSARIUM HEAD BLIGHT RESISTANCE IN WINTER WHEAT CULTIVARS ART AND EVEREST by MARSHALL CLINESMITH B.S., Kansas State University, A THESIS submitted in partial fulfillment of the requirements for the degree MASTER OF SCIENCE Department of Agronomy College.

qtl mapping of iron deficiency chlorosis tolerance in soybean using connected populations a thesis submitted to the faculty of the graduate school.

A quantitative trait locus (QTL) is a locus (section of DNA) which correlates with variation of a quantitative trait in the phenotype of a population of organisms.

QTLs are mapped by identifying which molecular markers (such as SNPs or AFLPs). WHITE MOLD RESISTANCE - ASSOCIATION MAPPING AND QTL IDENTIFICATION IN COMMON BEAN By ORITSESANINORMI BLESSING ORAGUZIE A thesis submitted in partial fulfillment of.

Quantitative Trait Locus (QTL) MappingCMB lecture 9 Eric Xing Backcross experiment. 2 F 2 intercross experiment Trait distributions: a classical view. 3 Another representation of a trait distribution Note the equivalent of dominance in our trait distributions.

A second example.

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Qtl mapping thesis
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