Systematics Section / ASPT
Raveill, Jay A. , Salah, Sally M. , Wolf, Haley J. , Nikaido, Selene S. .
Hybridization Between a Native and an Introduced Mulberry (Morus:Moraceae) in North America.
TWO mulberry species are native to North America and they have largely allopatric ranges. Red mulberry (Morus rubra) has a wide distribution in the US from the Great Plains to the east coast and just into southern Canada. Texas mulberry (Morus microphylla) occurs in the southwest and Mexico. The Asian White mulberry (Morus alba), the food plant of the domesticated silkworm, was introduced into North America as a part of an unsuccessful effort to establish a silk industry and is also used in horticulture. The current distribution of white mulberry in North America now includes nearly if not all of the range of red mulberry. Hybridization between red and white mulberry has long been suspected based on intermediate leaf morphology but the inherent variability shown by the leaves of both species makes determination of hybrid individuals difficult. Recently hybridization has been conclusively demonstrated at the edge of the range of red mulberry using RAPD markers. We examined nuclear DNA (ITS1 and ITS2) and cpDNA (trnL-F) DNA sequences for species-specific markers that could distinguish mulberry species. Samples tentatively identified as red or white mulberry had sequences that clustered into two clearly defined groups and sequences from white mulberry clustered with GenBank sequences from Asian mulberry species including M. alba. Some individuals with intermediate morphology have two ITS sequences, one from each parental species. The species-specific differences included an RFLP site that greatly facilitated screen large numbers of samples. Habitat preferences are seen as critical in preventing the genetic swamping through hybridization of a common native species by an aggressive introduced species.
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1 - Central Missouri State University, Department of Biology and Earth Science, Warrensburg, Missouri, 64093, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 134/Performing Arts Center
Date: Tuesday, August 1st, 2006
Time: 9:00 AM