Fig 1.

Crossing strategies used to generate the congenic strains XL280a and XL280α in this study and their relationship with other C. neoformans congenic pairs. NIH12 is a clinical isolate, and NIH433 is an environmental isolate (27, 29). B3501 and B3502 were generated from a cross between NIH12 and NIH433, and they were used to generate the first congenic pair, JEC21 and JEC20, in 1992 (27–29). Two other congenic pairs in the genetic background of NIH433 and B3501 were generated in 2005 (33). XL280p was generated previously by crossing B3501 and B3502 and was found to be hyperfilamentous on a variety of nutrient-limiting solid media (54). Based on next generation sequencing analysis, the genome sequence of XL280 is 81% identical to that of JEC21 (J. Heitman, personal communication). *, B3502 is nearly isogenic with JEC20 based on two previous studies (33, 58).