Since chromosomes have been brought in.
On the paternal side, southern Hans and northern Hans share similar frequencies of Y-chromosome haplogroups (Supplementary Table 2), which are characterized by two haplogroups carrying the M122-C mutations (O3-M122 and O3e-M134) that are prevalent in almost all Han populations studied (mean and range: 53.8%, 3771%; 54.2%, 3574%, for northern and southern Hans, respectively).
Haplogroups carrying M119-C (O1* and O1b) and/or M95-T (O2a* and O2a1) (following the nomenclature of the Y Chromosome Consortium) which are prevalent in southern natives, are more frequent in southern Hans (19%, 342%) than in northern Hans (5%, 110%). In addition, haplogroups O1b-M110, O2a1-M88 and O3d-M7, which are prevalent in southern natives17, were only observed in some southern Hans (4% on average), but not in northern Hans.
Therefore, the contribution of southern natives in southern Hans is limited, if we assume that the frequency distribution of Y lineages in southern natives
represents that before the expansion of Han culture that started 2,000 yr ago5. The results of analysis of molecular variance (AMOVA) further indicate that northern Hans and southern Hans are not significantly different in their Y haplogroups (FST ¼ 0.006, P . 0.05),
demonstrating that southern Hans bear
a high resemblance to northern Hans in their male lineages.
On the maternal side, however, the mtDNA haplogroup
distribution showed substantial differentiation between northern Hans and southern Hans (Supplementary Table 3).
http://159.226.149.45/compgenegroup/...(2004).pdf
It does indicate much about the chromosomes, the original identity of the people of the two regions and how it was 'merged'.
And it is not Wikipedia for the usual debunking brigade up in arms to obfuscate filling everything with irrelevance and not permit sane discussion.