We next directly compared methylation levels at orthologous CGIs and noted a general trend of similar CGIs gaining methylation in our ectopic Dnmt3b tissues, chronic lymphocytic leukemia (CLL) and early postimplantation mouse extraembryonic ectoderm (ExE) (Figure 6—figure supplement 1C). Here, DNMT3B is linked to B-cell chronic lymphocytic leukemia.