Resumen

WINSETT, Katherine E.  y  STEPHENSON, Steven L.. Using ITS sequences to assess intraspecific genetic relationships among geographically separated collections of the myxomycete Didymium squamulosum. Rev. Mex. Mic [online]. 2008, vol.27, pp.59-65. ISSN 0187-3180.

An analysis of ITS sequences of Didymium squamulosum, a myxomycete regarded as cosmopolitan, shows variation among geographically separated isolates. ITS 1 and 2 and 5.8S rDNA were amplified from specimens collected in widely scattered localities. The sequences were analyzed by parsimony analysis and the resulting trees show separate, moderate and well supported clades grouping some, but not all, of the geographic locations. ITS is the first molecular marker examined for intraspecific variation in myxomycetes, and although sequence analysis shows statistically significant differences among sequences from the 14 specimens considered, the heterogeneity in ITS 1 and ITS 2 appears to be too great for any more meaningful biogeographical conclusions. Variation in the 5.8S and the amount of variation found in ITS 1 and 2 may signify that the isolates examined represent a complex of sibling species, although this particular marker cannot be used to make that distinction in this myxomycete.

Palabras llave : ITS; intraspecific variation.

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