| low intraspecific variation for genomic isolation between hybridizing sunflower species. | barriers to gene flow between species result from selection against foreign linkage blocks in hybrids. when the geographic ranges of taxa meet at multiple locations, the opportunity exists for variation in the genetic architecture of isolating barriers. hybrid zones between two sunflower species (helianthus annuus and h. petiolaris) in nebraska and california exhibited remarkably similar patterns of introgression of mapped molecular markers. congruence among hybrid zones may result from limited ... | 2001 | 11392386 |