https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2765279/figure/F4/ Day 261 has 107 protein-coding genes (browser view) including DNAH10OS (dynein, axonemal, heavy chain 10 opposite strand).
Like Day 258 (12q21.33-12q23.1): CLLU1, a human-specific gene, DNAH10OS is one of the very rare cases of human-specific genes.
Click here to see all 8329707 letters of Day 261 with DNAH10OS underlined.