Comparisons between the Y chromosome SNP and MtDNA of modern Northern Han Chinese and 3,000 year old Hengbei ancient samples from China's Central Plains show they are extremely similar to each other and show continuity between ancient Chinese of Hengbei and current Northern Han Chinese. This showed that already 3,000 years ago the current northern Han Chinese genetic structure was already formed. The reference population for the Chinese used in Geno 2.0 Next Generation is 81% Eastern Asia, 2% Finland and Northern Siberia, 8% Central Asia, and 7% Southeast Asia & Oceania.