On the multilocus genotypic frequencies in recombinant inbred, advanced intercrossed populations from 2- and 4-way cross of inbred lines
碩士 === 國立臺灣大學 === 農藝學研究所 === 101 === Genetic markers such as DNA have long been used to represent the genotype of an individual (precisely, a lineage) by geneticists and breeders. These markers are developed by some means throughout the genome of the particular organism and being genotyped. Polymorp...
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| Format: | Others |
| Language: | en_US |
| Published: |
2013
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| Online Access: | http://ndltd.ncl.edu.tw/handle/65324212480180880048 |
| Summary: | 碩士 === 國立臺灣大學 === 農藝學研究所 === 101 === Genetic markers such as DNA have long been used to represent the genotype of an individual (precisely, a lineage) by geneticists and breeders. These markers are developed by some means throughout the genome of the particular organism and being genotyped. Polymorphism of each marker characterizes different individuals. The characterization would be much more specific with the amount of polymorphic genetic markers we recognized. The genotypes of these markers are associated with the phenotypic values in the mapping of quantitative trait loci (QTL). In this study, we derived the multilocus genotypic frequencies for recombinant inbred and advanced intercrossed populations from 2- and 4-way crosses of inbred lines. We provide the mathematical proof for the relationship between the theoretical genotypic frequencies and the recombination scores of individual in the selfed populations derived from biparental cross of inbred lines. It is showed that genotypes with the same recombination score would have the equal probability to show up in any generation beyond the F2. This arisen symmetry also has its similar variants in 2-way random mating as well as 4-way selfing and random mating populations. Multi-level recombination score is proposed to identify the gametes with the same theoretical frequency among the random-mated 4-way cross derivatives. By using these symmetries, we reduced the dimensions of frequencies-transition matrix for each population. The reduction of matrix size lightens the computation effort in the multiplications for obtaining the advanced generation genotypic frequencies. At the end of this study, we provide a simple simulated case studying involving a biparental selfed F6 population and its multiple interval QTL mapping.
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