It’s well known that incorporating some existing populations derived from multiple parents may improve QTL mapping and QTL-based breeding programs. However, no general maximum likelihood method has been available for this strategy. Based on the QTL mapping in multiple related populations derived from two parents, a maximum likelihood estimation method was proposed, which can incorporate several populations derived from three or more parents and also can be used to handle different mating designs. Taking a circle design as an example, we conducted simulation studies to study the effect of QTL heritability and sample size upon the proposed method. The results showed that under the same heritability, enhanced power of QTL detection and more precise and accurate estimation of parameters could be obtained when three F2 populations were jointly analyzed, compared with the joint analysis of any two F2 populations. Higher heritability, especially with larger sample sizes, would increase the ability of QTL detection and improve the estimation of parameters. Potential advantages of the method are as follows: firstly, the existing results of QTL mapping in single population can be compared and integrated with each other with the proposed method, therefore the ability of QTL detection and precision of QTL mapping can be improved. Secondly, owing to multiple alleles in multiple parents, the method can exploit gene resource more adequately, which will lay an important genetic groundwork for plant improvement.
AO Yan, HU Zhi-qiu, TANG Zai-xiang, WANG Xue-feng, XU Chen-wu
. A General Method for QTL Mapping in Multiple Related Populations Derived from Multiple Parents[J]. Rice Science, 2009
, 16(1)
: 45
-50
.
DOI: 10.1016/S1672-6308(08)60055-4
1 Xu S. Mapping quantitative trait loci using four-way crosses. Genet Res, 1996, 68: 175–181.
2 Xie C, Gessler D D, Xu S. Combining different line crosses for mapping quantitative trait loci using the identical by descent-based variance component method. Genetics, 1998, 149(2): 1139–1146.
3 Yi N, Xu S. Linkage analysis of quantitative trait loci in multiple line crosses. Genetica, 2002, 114(3): 217–230.
4 Ao Y. Method for QTL mapping under complicated mating designs [PHD Dissertation]. Yangzhou: Yangzhou University, 2007.
5 Muranty H. Power of tests for quantitative trait loci detection using full-sib familiars in different schemes. Heredity, 1996, 76: 56–165.
6 Xu S. Mapping quantitative trait loci using multiple families of line crosses. Genetics, 1998, 148(1): 517–524.
7 Rebai A, Goffinet B. More about quantitative trait locus mapping with diallel designs. Genet Res, 2000, 75(2): 243– 247.
8 Liu Y, Zeng Z B. A general mixture model approach for mapping quantitative trait loci from diverse cross designs involving multiple inbred lines. Genet Res, 2000, 75(3): 345–355.
9 Xie C, Gessler D D, Xu S. Combining different line crosses for mapping quantitative trait loci using the identical by descent-based variance component method. Genetics, 1998, 149(2): 1139–1146.
10 Piepho H P. A quick method for computing approximate thresholds for quantitative trait loci detection. Genetics, 2001, 157(1): 425–432.
11 Soller M, Brody T, Genizi A. On the power of experi- mental designs for the detection of linkage between marker loci and quantitative loci in crosses between inbred lines. Theor Appl Genet, 1976, 47(1): 35–39.
12 Lander E S, Botstein D. Mapping Mendelian factors underlying quantitative traits using RFLP linkage maps. Genetics, 1989, 121(1): 185–199.
13 Haley C S, Knott S A. A simple regression method for mapping quantitative trait loci in line crosses using flanking markers. Heredity, 1992, 69(4): 315–324.
14 Martínez O, Curnow R N. Estimating the locations and the sizes of effects of quantitative trait loci using flanking markers. Theor Appl Genet, 1992, 85: 480–488.
15 Jansen R C, Stam P. High resolution of quantitative traits into multiple loci via interval mapping. Genetics, 1994, 136: 1447–1455.
16 Zeng Z B. Precision mapping of quantitative trait loci. Genetics, 1994, 136(4): 1457–1468.
17 Kao C H, Zeng Z B, Teasdale R D. Multiple interval mapping for quantitative trait loci. Genetics, 1999, 152(3): 1203–1216.
18 Wang D L, Zhu J, Li Z K, Paterson A H. Mapping QTLs with epistatic effects and QTL environment interactions by mixed linear model approaches. Theor Appl Genet, 1999, 99: 1255– 1264.
19 Feenstra B. Mapping quantitative trait loci in inbred line crosses [PHD Dissertation]. Copenhagen: Royal Veterinary and Agricultural University, 2005.
