Abstract
This article investigates the efficiency of marker-assisted selection in reducing the length of the donor chromosome segment retained around a locus held heterozygous by backcrossing. First, the efficiency of marker-assisted selection is evaluated from the length of the donor segment in backcrossed individuals that are (double) recombinants for two markers flanking the introgressed gene on each side. Analytical expressions for the probability density function, the mean, and the variance of this length are given for any number of backcross generations, as well as numerical applications. For a given marker distance, the number of backcross generations performed has little impact on the reduction of donor segment length, except for distant markers. In practical situations, the most important parameter is the distance between the introgressed gene and the flanking markers, which should be chosen to be as closely linked as possible to the introgressed gene. Second, the minimal population sizes required to obtain double recombinants for such closely linked markers are computed and optimized in the context of a multigeneration backcross program. The results indicate that it is generally more profitable to allow for three or more successive backcross generations rather than to favor recombinations in early generations.
Full Text
The Full Text of this article is available as a PDF (177.7 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Frisch M., Melchinger A. E. The length of the intact donor chromosome segment around a target gene in marker-assisted backcrossing. Genetics. 2001 Mar;157(3):1343–1356. doi: 10.1093/genetics/157.3.1343. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hanson W D. Early Generation Analysis of Lengths of Heterozygous Chromosome Segments around a Locus Held Heterozygous with Backcrossing or Selfing. Genetics. 1959 Sep;44(5):833–837. doi: 10.1093/genetics/44.5.833. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hillel J., Schaap T., Haberfeld A., Jeffreys A. J., Plotzky Y., Cahaner A., Lavi U. DNA fingerprints applied to gene introgression in breeding programs. Genetics. 1990 Mar;124(3):783–789. doi: 10.1093/genetics/124.3.783. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hospital F., Charcosset A. Marker-assisted introgression of quantitative trait loci. Genetics. 1997 Nov;147(3):1469–1485. doi: 10.1093/genetics/147.3.1469. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hospital F., Chevalet C., Mulsant P. Using markers in gene introgression breeding programs. Genetics. 1992 Dec;132(4):1199–1210. doi: 10.1093/genetics/132.4.1199. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Naveira H., Barbadilla A. The theoretical distribution of lengths of intact chromosome segments around a locus held heterozygous with backcrossing in a diploid species. Genetics. 1992 Jan;130(1):205–209. doi: 10.1093/genetics/130.1.205. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Visscher P. M., Haley C. S., Thompson R. Marker-assisted introgression in backcross breeding programs. Genetics. 1996 Dec;144(4):1923–1932. doi: 10.1093/genetics/144.4.1923. [DOI] [PMC free article] [PubMed] [Google Scholar]