Neanderthal and Denisovan whole-genome DNA methylation maps have been constructed using a method that analyses the degradation of methylated and unmethylated cytosine modifications, and these maps have been compared to those of modern-day humans. Around 2,000 differentially methylated regions were identified, including changes in regions that are likely to be associated with several diseases, such as neurological and psychiatric disorders. Changes in the HOXD gene cluster were also identified, and the authors propose that these changes might be responsible for anatomical differences between archaic and modern-day humans.