Figure 3.

Schematics of the construction of focal males for fertility tests for one pair of D. mauritiana introgressions (8.4/3.4) with the Ysech. Identical crosses and male fertility tests with the Ysim chromosome were performed simultaneously (not shown here). Shown here is A14/Ysech in the background genome of simB with homozygous D. mauritiana introgressions 8.4/3.4. Males from lines SR12-2-7/Ysech and G23/Ysech also provided Ysech chromosomes for assay with 8.4/3.4, 21.2/26.14 and 38.6/38.8. Males from lines A14/Ysim, SR12-2-7/Ysim and G23/Ysim provided Ysim chromosomes for the same introgression combinations cited above. Crosses and fertility assays were performed simultaneously for all treatments. Note that the focal male is identical across all cases. Male fertility was tested by crossing one male with three D. simulans w; e females for 7 days and subsequently counting the progeny. White bars represent chromosomes of D. simulans, black bars represent chromosomes of D. sechellia and gray bars represent segments of D. mauritiana third chromosome.