Selective spore trapping and molecular genotyping methods were employed to examine
potential long-distance gene flow among Caribbean populations of the common mushroom
Schizophyllum commune
. Spore-trap samples from five locations were analysed using restriction
fragment polymorphisms of five enzymatically amplified gene regions. Successful trappings
suggested
S. commune
spores to be abundant in the air, with an estimated sedimentation
rate of
»
18 spores/m
2
/h. High levels of genetic diversity characterized the spore-trap
samples, with as many as 12 alleles observed at a single locus (chitin synthase) over all samples.
In addition, spore-trap samples showed significant among sample heterogeneity including
geographical population substructure. The ribosomal DNA (rDNA) intergenic spacer displayed
the greatest allele frequency differences among samples, clearly separating the samples
into those possessing only a South American-type allele and those segregating for both North
and South American-type alleles. The molecular variation provided no clear evidence for
dispersal over large, aquatic barriers within the Caribbean region, and instead suggested that
spore-trapping experiments are primarily reflective of the local, established population.