GEOGRAPHICAL VARIATION IN ASIMINA-TRILOBA DUNAL (ANNONACEAE) REVEALED BY THE M13 DNA FINGERPRINTING PROBE

Genetic variation for variable DNA loci was investigated in Asimina triloba using the M13 "fingerprinting" probe. A survey of plants from widely separated sites across portions of the geographical range of the species showed that each site possessed a distinct set of DNA fragments. The probability of two individuals having identical fragment patterns was approximately 1/1,700 at this geographical range. Levels of variation at local sites were quite different than at a wide geographic scale. Within-population variation ranged from moderate levels to none. The fragment profile of a fruit-bearing tree was compared with those of nine of its offspring; all progeny were identical with the maternal parent, indicating that both the staminate and carpellate sources were homozygous at all detected loci. These results suggest that while genetic variation is detectable both among distant individuals and within some very local populations, clonal propagation and/or inbreeding have led to a lack of genetic variation in some populations of A. tribola.