The genetic basis of reproductive isolation: Insights from Drosophila

1. 

   View larger version:

   • In this window
   • In a new window

   • Download as PowerPoint Slide

   Fig. 1.

   The rate of increase in “total” reproductive isolation with genetic distance in Drosophila. Postzygotic isolation is measured such that a value of 0 means no reproductive isolation (either pre-or postzygotic) and a value of 1 means complete reproductive isolation. Genetic distance is measured by Nei's genetic distance, which increases approximately linearly with time over the values shown. Data include both allopatric and sympatric species pairs. Although the measure of total reproductive isolation shown includes aspects of both pre- and postzygotic isolation, it is imperfect and generally excludes forms of reproductive isolation (e.g., ecological isolation) that are not readily measured in the laboratory. Data are based on refs. 57 and 58. [Reproduced with permission from ref. 58 (Copyright 1997, International Journal of Organic Evolution).]

   
   
2. 

   View larger version:

   • In this window
   • In a new window

   • Download as PowerPoint Slide

   Fig. 2.

   Deficiency and complementation mapping of a hybrid inviability gene. The region shown corresponds to cytological region 95 of the third chromosome of D. melanogaster. Bars shown in gray below the chromosome uncover recessive hybrid inviability in D. melanogaster-D. simulans hybrids and those shown in black do not. Vertical lines represent known viability-essential complementation groups in the region. Hybrid inviability maps to a single locus, Nup96. Data are based on ref. 34. [Reproduced with permission from ref. 34 (Copyright 2003).]

   
   
3. 

   View larger version:

   • In this window
   • In a new window

   • Download as PowerPoint Slide

   Fig. 3.

   Regions of the D. pseudoobscura X chromosome implicated in hybrid sterility between the Bogota and USA subspecies (54). Recent genetic analysis of segregation distortion in the same hybridization implicates approximately the same chromosomal regions (53). The markers shown are all visible mutations. Kosambi-corrected map positions are provided. [Reproduced with permission from ref. 54 (Copyright 2001, Genetics Society of America).]

   
   
4. 

   View larger version:

   • In this window
   • In a new window

   • Download as PowerPoint Slide

   Fig. 4.

   Correlation between D. pseudoobscura Bogota-USA hybrid fertility (as measured by offspring production) and hybrid segregation distortion (as measured by offspring sex ratio). Each data point reflects the offspring of a single recombinant backcross generation male. Data are based on ref. 53. [Reproduced with permission from ref. 53 (Copyright 2005, Genetics Society of America).]