Fig 2. Karyotypic changes impact CT formation during spermatogenesis.

Top: Karyotype and resulting CTs during fly spermatogenesis. Drosophila wild-type karyotype and CTs are shown in A. (B–E) Show various mutant karyotypes and the resulting CTs. G1 chromosomes (unreplicated chromatids) are shown for simplicity. Centromeres are shown in gray. A genome with 3 major chromosomes leads to the formation of 3 CTs (A and C). Karyotypes with 4 major chromosomes lead to the formation of 4 CTs (B and E). When inter-chromosomal translocations occur (for example, between chromosomes 2 and 3; C), this leads to the formation of quadrivalents and results in 2 major CTs. Bottom: Karyotype and resulting CTs formed in Kc (somatic) cells (F and G). In this context, homology almost entirely dictates CT formation, regardless of the underlying karyotypic changes. CT, chromosome territory.