title: Establishment of F1 hybrid mortality in real time.
abstract: Measuring the evolutionary rate of reproductive isolation is essential to understanding how new species form. Tempo calculations typically rely on fossil records, geological events, and molecular evolution analyses. The speed at which genetically-based hybrid mortality arises, or the "incompatibility clock", is estimated to be millions of years in various diploid organisms and is poorly understood in general. Owing to these extended timeframes, seldom do biologists observe the evolution of hybrid mortality in real time.
  
  
  
  Here we report the very recent spread and fixation of complete asymmetric F1hybrid mortality within eight years of laboratory maintenance in the insect model Nasonia. The asymmetric interspecific hybrid mortality evolved in an isogenic stock line of N. longicornis and occurs in crosses to N. vitripennis males. The resulting diploid hybrids exhibit complete failure in dorsal closure during embryogenesis.
  
  
  
  These results comprise a unique case whereby a strong asymmetrical isolation barrier evolved in real time. The spread of this reproductive isolation barrier notably occurred in a small laboratory stock subject to recurrent bottlenecks.
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA.|Present Address: Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA.
authors.forename: Ashley
authors.initials: A
authors.lastname: Saulsberry
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA.|Present Address: Children's Hospital Los Angeles, Los Angeles, CA, 90027, USA.
authors.forename: Marisa
authors.initials: M
authors.lastname: Pinchas
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: Noll
authors.affiliation: Department of Biological Sciences, University of Illinois at Chicago, Chicago, USA.
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Lynch
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA. s.bordenstein@vanderbilt.edu.|Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN, 37235, USA. s.bordenstein@vanderbilt.edu.
authors.forename: Seth R
authors.initials: SR
authors.lastname: Bordenstein
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA. bruckerm@gmail.com.|The Rowland Institute at Harvard University, Harvard University, 100 Edwin H. Land Blvd, Cambridge, MA, 02142, USA. bruckerm@gmail.com.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Brucker
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005260:Female; D006824:Hybridization, Genetic; D008297:Male; D060047:Reproductive Isolation; D014863:Wasps / Q000235:genetics*
keywords: Development; Hybrid incompatibility; Nasonia; Reproductive isolation; Speciation