Three-point linkage analysis in crosses of allogamous plant species

Bitter & Salamini (1996) presented a systematic account of two-point linkag e analysis in allogamous diploid plant species. Vowden et al. (1995) descri bed an alternative approach that is implemented in a computer program LINKE M. This paper describes how the latter approach has been extended to three- point linkage analysis, and implemented in a new program LINK3EM, that is a vailable from the authors. The essence of the approach is for the computer program to derive the appropriate form of analysis for a specific cross fro m its 'knowledge' of the most general type of cross that can arise. This av oids the need for programming specific codes for the many different types o f cross that can arise. The program allows different locus orderings and pa rental phases to be compared. The Haldane or Kosambi map functions can be s pecified, although it is also possible to estimate all three pairwise recom bination fractions without any assumed map function.