ARS | Publication request: AFLP-DERIVED, CODOMINANT MARKERS FOR LOCUS-SPECIFIC APPLICATIONS

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: May 19, 1998
Publication Date: N/A

Technical Abstract: The amplified fragment length polymorphism (AFLP) is a powerful marker, allowing rapid and simultaneous evaluation of multiple potentially polymorphic sites. Although well-adapted to linkage mapping and diversity assessment, AFLPs are primarily dominant in nature. Dominance, relatively high cost, and technological difficulty limit use of AFLPs for marker-aided selection and other locus-specific applications. In carrot the Y2 locus conditions carotene accumulation in the root xylem. We identified AFLP fragments linked to the dominant Y2 allele and prusued conversion of those fragments to codominant, PCR-based forms useful for locus specific applications. The short length of AFLPs (60 to 500 bp) precludes development of longer, more specific primers as in SCAR development. Instead, using sequence information from cloned AFLP fragments for primer design, regions outside of the original fragment were amplified by inverse PCR or ligation-mediated allowed development of simple PCR assays differentiating those alleles. PCR primers flanking an insertion associated with the recessive allele amplified differently sizes products for the two Y2 alleles in one assay. This assay is rapid, technologically simple (requiring no radioactivity and little advanced training or equipment), reliable, inexpensive, and codominant. Our PCR assay has a variety of large scale, locus-specific applications including genotyping diverse carrot cultivars and wild and feral populations. Efforts are underway to improve upon conversion technology and to more extensively test the techniques we have developed.