hybrid speciation

Taylor SJ, Arnold M & Martin NH 2009 The genetic architecture of reproductive isolation in Louisiana irises: hybrid fitness in nature. Evolution 63:2581-2594.

• a "genic view of speciation" specifically allows for large swaths of the genome to be permeable to introgression
• with species differentiation potentially occurring in the presence of only a small number of "speciation genes"
• not all heterospecific alleles decrease the fitness of hybrids
• at least some portions of the genome may be permeable to introgression of advantageous and/or neutral genomic regions