Skip to main content
. Author manuscript; available in PMC: 2020 Jul 10.
Published in final edited form as: Science. 2020 Apr 17;368(6488):eaba0712. doi: 10.1126/science.aba0712

Figure 2. Immediate effect of chromosome bridge breakage on DNA copy number.

Figure 2.

(A) Cartoon illustrating Look-Seq experiments.

(B) Type 1 events are daughter cells with reciprocal gain and loss of a terminal chromosome segment. Top: Sister (left) and Non-sister (right) chromatid fusions. In mitosis, the resulting dicentrics are segregated (green dashed arrows), forming a bridge. Bridge breakage (dashed red line) produces copy number alterations as shown. Bottom: representative copy number plot (gray dots, 1-Mb bins for the affected Chr2 haplotype). Red bar: inferred bridge breakpoint. Light gray bar: centromere.

(C) Type 2 events are reciprocal gain and loss of an internal chromosome segment between the daughter cells. Top: a chromosome fusion (40). If the kinetochores of each dicentric attach to microtubules from opposite poles as shown (dashed green arrows), the dicentric chromatids invert relative to each other. Cleavage of the antiparallel chromatid pair yields reciprocal copy number alterations of an internal chromosome segment. Bottom: DNA copy number plot as in (B).