Complications of polyploidy and outcrossing
For reasons of simplicity, in this module we have mainly used the more common diploid inbred types of crop species as examples. However, many crops are outcrossers (eg. cassava) or polyploid (potato, wheat, etc.). The basic principles of genetic mapping, QTL analysis and MAB are the same, but the data scoring and analysis is more complicated. More alleles may be seen at each marker, for example, and some alleles may show variable dosage.
Below are examples of marker use in more complex situations:
Feingold S, Lloyd J, Norero N, Bonierbale M, Lorenzen J (2005) Mapping and characterization of new EST-derived microsatellites for potato (Solanum tuberosum L.). Theoretical and Applied Genetics 111: 456-466.
Leonard-Schippers C, Gieffers W, Schäfer-Pregl R, Ritter E, Knapp SJ, Salamini F, Gebhardt C (1994) Quantitative resistance to Phytophthora infestans in potato: a case study for QTL mapping in an allogamous plant species. Genetics 137: 67-77.
Troggio M, Malacarne G, Coppola G, Segala C, Cartwright DA, Pindo M, Stefanini M, Mank R, Moroldo M, Morgante M, Grando MS, Velasco R (2007) A dense single-nucleotide polymorphism-based genetic linkage map of grapevine (Vitis vinifera L.) anchoring Pinot Noir Bacterial Artificial Chromosome contigs. Genetics 176: 2637-2650.