Plate 4.1

(a) Normal devil karyotype consisting of six pairs of autosomes and a pair of sex chromosomes (XX females, XY males). One copy of each chromosome has long telomeres (indicated by large dots at the ends of chromosomes) and one copy with short telomeres (small dots at the ends of chromosomes). (b) DFT1 karyotype showing the highly rearranged chromosome 1 and X present in Marker chromosomes (M1–M5), along with regions of chromosomes 4 and 5. All chromosomes have short telomeres. (c). Proposed fusion of chromosomes and X leading to the rearranged DFT1 karyotype. Telomeres eroded on one copy of chromosome 1 and X, permitting the fusion of these two chromosomes near the NF2 gene on chromosome 1. A series of breaks and fusions ultimately resulted in the formation of the highly rearranged M1 chromosome and the distribution of small fragments of chromosomes 1 and X to other chromosomes (2, M2 and 6). (Image: created by Janine Deakin)